Imported Upstream version 2.3.16-beta

10 files changed, 1494 insertions, 0 deletions

diff --git a/modules/proxy/balancers/Makefile.in b/modules/proxy/balancers/Makefile.in
new file mode 100644
index 00000000..7c5c149d
--- /dev/null
+++ b/modules/proxy/balancers/Makefile.in
@@ -0,0 +1,3 @@
+# a modules Makefile has no explicit targets -- they will be defined by
+# whatever modules are enabled. just grab special.mk to deal with this.
+include $(top_srcdir)/build/special.mk
diff --git a/modules/proxy/balancers/config2.m4 b/modules/proxy/balancers/config2.m4
new file mode 100644
index 00000000..f7232661
--- /dev/null
+++ b/modules/proxy/balancers/config2.m4
@@ -0,0 +1,8 @@
+APACHE_MODPATH_INIT(proxy/balancers)
+
+APACHE_MODULE(lbmethod_byrequests, Apache proxy Load balancing by request counting, , , $proxy_mods_enable)
+APACHE_MODULE(lbmethod_bytraffic, Apache proxy Load balancing by traffic counting, , , $proxy_mods_enable)
+APACHE_MODULE(lbmethod_bybusyness, Apache proxy Load balancing by busyness, , , $proxy_mods_enable)
+APACHE_MODULE(lbmethod_heartbeat, Apache proxy Load balancing from Heartbeats, , , $proxy_mods_enable)
+
+APACHE_MODPATH_FINISH
diff --git a/modules/proxy/balancers/mod_lbmethod_bybusyness.c b/modules/proxy/balancers/mod_lbmethod_bybusyness.c
new file mode 100644
index 00000000..9185f22f
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_bybusyness.c
@@ -0,0 +1,161 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mod_proxy.h"
+#include "scoreboard.h"
+#include "ap_mpm.h"
+#include "apr_version.h"
+#include "ap_hooks.h"
+
+module AP_MODULE_DECLARE_DATA lbmethod_bybusyness_module;
+
+static int (*ap_proxy_retry_worker_fn)(const char *proxy_function,
+        proxy_worker *worker, server_rec *s) = NULL;
+
+static proxy_worker *find_best_bybusyness(proxy_balancer *balancer,
+                                request_rec *r)
+{
+
+    int i;
+    proxy_worker **worker;
+    proxy_worker *mycandidate = NULL;
+    int cur_lbset = 0;
+    int max_lbset = 0;
+    int checking_standby;
+    int checked_standby;
+
+    int total_factor = 0;
+
+    if (!ap_proxy_retry_worker_fn) {
+        ap_proxy_retry_worker_fn =
+                APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker);
+        if (!ap_proxy_retry_worker_fn) {
+            /* can only happen if mod_proxy isn't loaded */
+            return NULL;
+        }
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01211)
+                 "proxy: Entering bybusyness for BALANCER (%s)",
+                 balancer->s->name);
+
+    /* First try to see if we have available candidate */
+    do {
+
+        checking_standby = checked_standby = 0;
+        while (!mycandidate && !checked_standby) {
+
+            worker = (proxy_worker **)balancer->workers->elts;
+            for (i = 0; i < balancer->workers->nelts; i++, worker++) {
+                if  (!checking_standby) {    /* first time through */
+                    if ((*worker)->s->lbset > max_lbset)
+                        max_lbset = (*worker)->s->lbset;
+                }
+                if (
+                    ((*worker)->s->lbset != cur_lbset) ||
+                    (checking_standby ? !PROXY_WORKER_IS_STANDBY(*worker) : PROXY_WORKER_IS_STANDBY(*worker)) ||
+                    (PROXY_WORKER_IS_DRAINING(*worker))
+                    ) {
+                    continue;
+                }
+
+                /* If the worker is in error state run
+                 * retry on that worker. It will be marked as
+                 * operational if the retry timeout is elapsed.
+                 * The worker might still be unusable, but we try
+                 * anyway.
+                 */
+                if (!PROXY_WORKER_IS_USABLE(*worker)) {
+                    ap_proxy_retry_worker_fn("BALANCER", *worker, r->server);
+                }
+
+                /* Take into calculation only the workers that are
+                 * not in error state or not disabled.
+                 */
+                if (PROXY_WORKER_IS_USABLE(*worker)) {
+
+                    (*worker)->s->lbstatus += (*worker)->s->lbfactor;
+                    total_factor += (*worker)->s->lbfactor;
+
+                    if (!mycandidate
+                        || (*worker)->s->busy < mycandidate->s->busy
+                        || ((*worker)->s->busy == mycandidate->s->busy && (*worker)->s->lbstatus > mycandidate->s->lbstatus))
+                        mycandidate = *worker;
+
+                }
+
+            }
+
+            checked_standby = checking_standby++;
+
+        }
+
+        cur_lbset++;
+
+    } while (cur_lbset <= max_lbset && !mycandidate);
+
+    if (mycandidate) {
+        mycandidate->s->lbstatus -= total_factor;
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01212)
+                     "proxy: bybusyness selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d",
+                     mycandidate->s->name, mycandidate->s->busy, mycandidate->s->lbstatus);
+
+    }
+
+    return mycandidate;
+
+}
+
+/* assumed to be mutex protected by caller */
+static apr_status_t reset(proxy_balancer *balancer, server_rec *s) {
+    int i;
+    proxy_worker **worker;
+    worker = (proxy_worker **)balancer->workers->elts;
+    for (i = 0; i < balancer->workers->nelts; i++, worker++) {
+        (*worker)->s->lbstatus = 0;
+        (*worker)->s->busy = 0;
+    }
+    return APR_SUCCESS;
+}
+
+static apr_status_t age(proxy_balancer *balancer, server_rec *s) {
+        return APR_SUCCESS;
+}
+
+static const proxy_balancer_method bybusyness =
+{
+    "bybusyness",
+    &find_best_bybusyness,
+    NULL,
+    &reset,
+    &age
+};
+
+
+static void register_hook(apr_pool_t *p)
+{
+    ap_register_provider(p, PROXY_LBMETHOD, "bybusyness", "0", &bybusyness);
+}
+
+AP_DECLARE_MODULE(lbmethod_bybusyness) = {
+    STANDARD20_MODULE_STUFF,
+    NULL,       /* create per-directory config structure */
+    NULL,       /* merge per-directory config structures */
+    NULL,       /* create per-server config structure */
+    NULL,       /* merge per-server config structures */
+    NULL,       /* command apr_table_t */
+    register_hook /* register hooks */
+};
diff --git a/modules/proxy/balancers/mod_lbmethod_bybusyness.dsp b/modules/proxy/balancers/mod_lbmethod_bybusyness.dsp
new file mode 100644
index 00000000..8544600c
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_bybusyness.dsp
@@ -0,0 +1,123 @@
+# Microsoft Developer Studio Project File - Name="mod_lbmethod_bybusyness" - Package Owner=<4>
+# Microsoft Developer Studio Generated Build File, Format Version 6.00
+# ** DO NOT EDIT **
+
+# TARGTYPE "Win32 (x86) Dynamic-Link Library" 0x0102
+
+CFG=mod_lbmethod_bybusyness - Win32 Release
+!MESSAGE This is not a valid makefile. To build this project using NMAKE,
+!MESSAGE use the Export Makefile command and run
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_bybusyness.mak".
+!MESSAGE 
+!MESSAGE You can specify a configuration when running NMAKE
+!MESSAGE by defining the macro CFG on the command line. For example:
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_bybusyness.mak" CFG="mod_lbmethod_bybusyness - Win32 Release"
+!MESSAGE 
+!MESSAGE Possible choices for configuration are:
+!MESSAGE 
+!MESSAGE "mod_lbmethod_bybusyness - Win32 Release" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE "mod_lbmethod_bybusyness - Win32 Debug" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE 
+
+# Begin Project
+# PROP AllowPerConfigDependencies 0
+# PROP Scc_ProjName ""
+# PROP Scc_LocalPath ""
+CPP=cl.exe
+MTL=midl.exe
+RSC=rc.exe
+
+!IF  "$(CFG)" == "mod_lbmethod_bybusyness - Win32 Release"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 0
+# PROP BASE Output_Dir "Release"
+# PROP BASE Intermediate_Dir "Release"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 0
+# PROP Output_Dir "Release"
+# PROP Intermediate_Dir "Release"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MD /W3 /O2 /D "WIN32" /D "NDEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MD /W3 /O2 /Oy- /Zi /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "NDEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Release\mod_lbmethod_bybusyness_src" /FD /c
+# ADD BASE MTL /nologo /D "NDEBUG" /win32
+# ADD MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "NDEBUG"
+# ADD RSC /l 0x409 /fo"Release/mod_lbmethod_bybusyness.res" /i "../../../include" /i "../../../srclib/apr/include" /d "NDEBUG" /d BIN_NAME="mod_lbmethod_bybusyness.so" /d LONG_NAME="lbmethod_bybusyness_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /out:".\Release\mod_lbmethod_bybusyness.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bybusyness.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Release\mod_lbmethod_bybusyness.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bybusyness.so /opt:ref
+# Begin Special Build Tool
+TargetPath=.\Release\mod_lbmethod_bybusyness.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ELSEIF  "$(CFG)" == "mod_lbmethod_bybusyness - Win32 Debug"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 1
+# PROP BASE Output_Dir "Debug"
+# PROP BASE Intermediate_Dir "Debug"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 1
+# PROP Output_Dir "Debug"
+# PROP Intermediate_Dir "Debug"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MDd /W3 /EHsc /Zi /Od /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MDd /W3 /EHsc /Zi /Od /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "_DEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Debug\mod_lbmethod_bybusyness_src" /FD /c
+# ADD BASE MTL /nologo /D "_DEBUG" /win32
+# ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "_DEBUG"
+# ADD RSC /l 0x409 /fo"Debug/mod_lbmethod_bybusyness.res" /i "../../../include" /i "../../../srclib/apr/include" /d "_DEBUG" /d BIN_NAME="mod_lbmethod_bybusyness.so" /d LONG_NAME="lbmethod_bybusyness_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_bybusyness.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bybusyness.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_bybusyness.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bybusyness.so
+# Begin Special Build Tool
+TargetPath=.\Debug\mod_lbmethod_bybusyness.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ENDIF 
+
+# Begin Target
+
+# Name "mod_lbmethod_bybusyness - Win32 Release"
+# Name "mod_lbmethod_bybusyness - Win32 Debug"
+# Begin Group "Source Files"
+
+# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;hpj;bat;for;f90"
+# Begin Source File
+
+SOURCE=.\mod_lbmethod_bybusyness.c
+# End Source File
+# End Group
+# Begin Group "Header Files"
+
+# PROP Default_Filter ".h"
+# Begin Source File
+
+SOURCE=..\mod_proxy.h
+# End Source File
+# End Group
+# Begin Source File
+
+SOURCE=..\..\..\build\win32\httpd.rc
+# End Source File
+# End Target
+# End Project
diff --git a/modules/proxy/balancers/mod_lbmethod_byrequests.c b/modules/proxy/balancers/mod_lbmethod_byrequests.c
new file mode 100644
index 00000000..015de12a
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_byrequests.c
@@ -0,0 +1,198 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mod_proxy.h"
+#include "scoreboard.h"
+#include "ap_mpm.h"
+#include "apr_version.h"
+#include "ap_hooks.h"
+
+module AP_MODULE_DECLARE_DATA lbmethod_byrequests_module;
+
+static int (*ap_proxy_retry_worker_fn)(const char *proxy_function,
+        proxy_worker *worker, server_rec *s) = NULL;
+
+/*
+ * The idea behind the find_best_byrequests scheduler is the following:
+ *
+ * lbfactor is "how much we expect this worker to work", or "the worker's
+ * normalized work quota".
+ *
+ * lbstatus is "how urgent this worker has to work to fulfill its quota
+ * of work".
+ *
+ * We distribute each worker's work quota to the worker, and then look
+ * which of them needs to work most urgently (biggest lbstatus).  This
+ * worker is then selected for work, and its lbstatus reduced by the
+ * total work quota we distributed to all workers.  Thus the sum of all
+ * lbstatus does not change.(*)
+ *
+ * If some workers are disabled, the others will
+ * still be scheduled correctly.
+ *
+ * If a balancer is configured as follows:
+ *
+ * worker     a    b    c    d
+ * lbfactor  25   25   25   25
+ *
+ * And b gets disabled, the following schedule is produced:
+ *
+ *    a c d a c d a c d ...
+ *
+ * Note that the above lbfactor setting is the *exact* same as:
+ *
+ * worker     a    b    c    d
+ * lbfactor   1    1    1    1
+ *
+ * Asymmetric configurations work as one would expect. For
+ * example:
+ *
+ * worker     a    b    c    d
+ * lbfactor   1    1    1    2
+ *
+ * would have a, b and c all handling about the same
+ * amount of load with d handling twice what a or b
+ * or c handles individually. So we could see:
+ *
+ *   b a d c d a c d b d ...
+ *
+ */
+
+static proxy_worker *find_best_byrequests(proxy_balancer *balancer,
+                                request_rec *r)
+{
+    int i;
+    int total_factor = 0;
+    proxy_worker **worker;
+    proxy_worker *mycandidate = NULL;
+    int cur_lbset = 0;
+    int max_lbset = 0;
+    int checking_standby;
+    int checked_standby;
+
+    if (!ap_proxy_retry_worker_fn) {
+        ap_proxy_retry_worker_fn =
+                APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker);
+        if (!ap_proxy_retry_worker_fn) {
+            /* can only happen if mod_proxy isn't loaded */
+            return NULL;
+        }
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01207)
+                 "proxy: Entering byrequests for BALANCER (%s)",
+                 balancer->s->name);
+
+    /* First try to see if we have available candidate */
+    do {
+        checking_standby = checked_standby = 0;
+        while (!mycandidate && !checked_standby) {
+            worker = (proxy_worker **)balancer->workers->elts;
+            for (i = 0; i < balancer->workers->nelts; i++, worker++) {
+                if (!checking_standby) {    /* first time through */
+                    if ((*worker)->s->lbset > max_lbset)
+                        max_lbset = (*worker)->s->lbset;
+                }
+                if (
+                    ((*worker)->s->lbset != cur_lbset) ||
+                    (checking_standby ? !PROXY_WORKER_IS_STANDBY(*worker) : PROXY_WORKER_IS_STANDBY(*worker)) ||
+                    (PROXY_WORKER_IS_DRAINING(*worker))
+                    ) {
+                    continue;
+                }
+
+                /* If the worker is in error state run
+                 * retry on that worker. It will be marked as
+                 * operational if the retry timeout is elapsed.
+                 * The worker might still be unusable, but we try
+                 * anyway.
+                 */
+                if (!PROXY_WORKER_IS_USABLE(*worker))
+                    ap_proxy_retry_worker_fn("BALANCER", *worker, r->server);
+                /* Take into calculation only the workers that are
+                 * not in error state or not disabled.
+                 */
+                if (PROXY_WORKER_IS_USABLE(*worker)) {
+                    (*worker)->s->lbstatus += (*worker)->s->lbfactor;
+                    total_factor += (*worker)->s->lbfactor;
+                    if (!mycandidate || (*worker)->s->lbstatus > mycandidate->s->lbstatus)
+                        mycandidate = *worker;
+                }
+            }
+            checked_standby = checking_standby++;
+        }
+        cur_lbset++;
+    } while (cur_lbset <= max_lbset && !mycandidate);
+
+    if (mycandidate) {
+        mycandidate->s->lbstatus -= total_factor;
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01208)
+                     "proxy: byrequests selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d",
+                     mycandidate->s->name, mycandidate->s->busy, mycandidate->s->lbstatus);
+
+    }
+
+    return mycandidate;
+}
+
+/* assumed to be mutex protected by caller */
+static apr_status_t reset(proxy_balancer *balancer, server_rec *s) {
+    int i;
+    proxy_worker **worker;
+    worker = (proxy_worker **)balancer->workers->elts;
+    for (i = 0; i < balancer->workers->nelts; i++, worker++) {
+        (*worker)->s->lbstatus = 0;
+    }
+    return APR_SUCCESS;
+}
+
+static apr_status_t age(proxy_balancer *balancer, server_rec *s) {
+        return APR_SUCCESS;
+}
+
+/*
+ * How to add additional lbmethods:
+ *   1. Create func which determines "best" candidate worker
+ *      (eg: find_best_bytraffic, above)
+ *   2. Register it as a provider.
+ */
+static const proxy_balancer_method byrequests =
+{
+    "byrequests",
+    &find_best_byrequests,
+    NULL,
+    &reset,
+    &age
+};
+
+static void register_hook(apr_pool_t *p)
+{
+    /* Only the mpm_winnt has child init hook handler.
+     * make sure that we are called after the mpm
+     * initializes and after the mod_proxy
+     */
+    ap_register_provider(p, PROXY_LBMETHOD, "byrequests", "0", &byrequests);
+}
+
+AP_DECLARE_MODULE(lbmethod_byrequests) = {
+    STANDARD20_MODULE_STUFF,
+    NULL,       /* create per-directory config structure */
+    NULL,       /* merge per-directory config structures */
+    NULL,       /* create per-server config structure */
+    NULL,       /* merge per-server config structures */
+    NULL,       /* command apr_table_t */
+    register_hook /* register hooks */
+};
diff --git a/modules/proxy/balancers/mod_lbmethod_byrequests.dsp b/modules/proxy/balancers/mod_lbmethod_byrequests.dsp
new file mode 100644
index 00000000..cfa90bfe
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_byrequests.dsp
@@ -0,0 +1,123 @@
+# Microsoft Developer Studio Project File - Name="mod_lbmethod_byrequests" - Package Owner=<4>
+# Microsoft Developer Studio Generated Build File, Format Version 6.00
+# ** DO NOT EDIT **
+
+# TARGTYPE "Win32 (x86) Dynamic-Link Library" 0x0102
+
+CFG=mod_lbmethod_byrequests - Win32 Release
+!MESSAGE This is not a valid makefile. To build this project using NMAKE,
+!MESSAGE use the Export Makefile command and run
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_byrequests.mak".
+!MESSAGE 
+!MESSAGE You can specify a configuration when running NMAKE
+!MESSAGE by defining the macro CFG on the command line. For example:
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_byrequests.mak" CFG="mod_lbmethod_byrequests - Win32 Release"
+!MESSAGE 
+!MESSAGE Possible choices for configuration are:
+!MESSAGE 
+!MESSAGE "mod_lbmethod_byrequests - Win32 Release" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE "mod_lbmethod_byrequests - Win32 Debug" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE 
+
+# Begin Project
+# PROP AllowPerConfigDependencies 0
+# PROP Scc_ProjName ""
+# PROP Scc_LocalPath ""
+CPP=cl.exe
+MTL=midl.exe
+RSC=rc.exe
+
+!IF  "$(CFG)" == "mod_lbmethod_byrequests - Win32 Release"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 0
+# PROP BASE Output_Dir "Release"
+# PROP BASE Intermediate_Dir "Release"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 0
+# PROP Output_Dir "Release"
+# PROP Intermediate_Dir "Release"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MD /W3 /O2 /D "WIN32" /D "NDEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MD /W3 /O2 /Oy- /Zi /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "NDEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Release\mod_lbmethod_byrequests_src" /FD /c
+# ADD BASE MTL /nologo /D "NDEBUG" /win32
+# ADD MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "NDEBUG"
+# ADD RSC /l 0x409 /fo"Release/mod_lbmethod_byrequests.res" /i "../../../include" /i "../../../srclib/apr/include" /d "NDEBUG" /d BIN_NAME="mod_lbmethod_byrequests.so" /d LONG_NAME="lbmethod_byrequests_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /out:".\Release\mod_lbmethod_byrequests.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_byrequests.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Release\mod_lbmethod_byrequests.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_byrequests.so /opt:ref
+# Begin Special Build Tool
+TargetPath=.\Release\mod_lbmethod_byrequests.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ELSEIF  "$(CFG)" == "mod_lbmethod_byrequests - Win32 Debug"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 1
+# PROP BASE Output_Dir "Debug"
+# PROP BASE Intermediate_Dir "Debug"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 1
+# PROP Output_Dir "Debug"
+# PROP Intermediate_Dir "Debug"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MDd /W3 /EHsc /Zi /Od /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MDd /W3 /EHsc /Zi /Od /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "_DEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Debug\mod_lbmethod_byrequests_src" /FD /c
+# ADD BASE MTL /nologo /D "_DEBUG" /win32
+# ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "_DEBUG"
+# ADD RSC /l 0x409 /fo"Debug/mod_lbmethod_byrequests.res" /i "../../../include" /i "../../../srclib/apr/include" /d "_DEBUG" /d BIN_NAME="mod_lbmethod_byrequests.so" /d LONG_NAME="lbmethod_byrequests_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_byrequests.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_byrequests.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_byrequests.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_byrequests.so
+# Begin Special Build Tool
+TargetPath=.\Debug\mod_lbmethod_byrequests.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ENDIF 
+
+# Begin Target
+
+# Name "mod_lbmethod_byrequests - Win32 Release"
+# Name "mod_lbmethod_byrequests - Win32 Debug"
+# Begin Group "Source Files"
+
+# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;hpj;bat;for;f90"
+# Begin Source File
+
+SOURCE=.\mod_lbmethod_byrequests.c
+# End Source File
+# End Group
+# Begin Group "Header Files"
+
+# PROP Default_Filter ".h"
+# Begin Source File
+
+SOURCE=..\mod_proxy.h
+# End Source File
+# End Group
+# Begin Source File
+
+SOURCE=..\..\..\build\win32\httpd.rc
+# End Source File
+# End Target
+# End Project
diff --git a/modules/proxy/balancers/mod_lbmethod_bytraffic.c b/modules/proxy/balancers/mod_lbmethod_bytraffic.c
new file mode 100644
index 00000000..ee245155
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_bytraffic.c
@@ -0,0 +1,168 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mod_proxy.h"
+#include "scoreboard.h"
+#include "ap_mpm.h"
+#include "apr_version.h"
+#include "ap_hooks.h"
+
+module AP_MODULE_DECLARE_DATA lbmethod_bytraffic_module;
+
+static int (*ap_proxy_retry_worker_fn)(const char *proxy_function,
+        proxy_worker *worker, server_rec *s) = NULL;
+
+/*
+ * The idea behind the find_best_bytraffic scheduler is the following:
+ *
+ * We know the amount of traffic (bytes in and out) handled by each
+ * worker. We normalize that traffic by each workers' weight. So assuming
+ * a setup as below:
+ *
+ * worker     a    b    c
+ * lbfactor   1    1    3
+ *
+ * the scheduler will allow worker c to handle 3 times the
+ * traffic of a and b. If each request/response results in the
+ * same amount of traffic, then c would be accessed 3 times as
+ * often as a or b. If, for example, a handled a request that
+ * resulted in a large i/o bytecount, then b and c would be
+ * chosen more often, to even things out.
+ */
+static proxy_worker *find_best_bytraffic(proxy_balancer *balancer,
+                                         request_rec *r)
+{
+    int i;
+    apr_off_t mytraffic = 0;
+    apr_off_t curmin = 0;
+    proxy_worker **worker;
+    proxy_worker *mycandidate = NULL;
+    int cur_lbset = 0;
+    int max_lbset = 0;
+    int checking_standby;
+    int checked_standby;
+
+    if (!ap_proxy_retry_worker_fn) {
+        ap_proxy_retry_worker_fn =
+                APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker);
+        if (!ap_proxy_retry_worker_fn) {
+            /* can only happen if mod_proxy isn't loaded */
+            return NULL;
+        }
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01209)
+                 "proxy: Entering bytraffic for BALANCER (%s)",
+                 balancer->s->name);
+
+    /* First try to see if we have available candidate */
+    do {
+        checking_standby = checked_standby = 0;
+        while (!mycandidate && !checked_standby) {
+            worker = (proxy_worker **)balancer->workers->elts;
+            for (i = 0; i < balancer->workers->nelts; i++, worker++) {
+                if (!checking_standby) {    /* first time through */
+                    if ((*worker)->s->lbset > max_lbset)
+                        max_lbset = (*worker)->s->lbset;
+                }
+                if (
+                    ((*worker)->s->lbset != cur_lbset) ||
+                    (checking_standby ? !PROXY_WORKER_IS_STANDBY(*worker) : PROXY_WORKER_IS_STANDBY(*worker)) ||
+                    (PROXY_WORKER_IS_DRAINING(*worker))
+                    ) {
+                    continue;
+                }
+
+                /* If the worker is in error state run
+                 * retry on that worker. It will be marked as
+                 * operational if the retry timeout is elapsed.
+                 * The worker might still be unusable, but we try
+                 * anyway.
+                 */
+                if (!PROXY_WORKER_IS_USABLE(*worker))
+                    ap_proxy_retry_worker_fn("BALANCER", *worker, r->server);
+                /* Take into calculation only the workers that are
+                 * not in error state or not disabled.
+                 */
+                if (PROXY_WORKER_IS_USABLE(*worker)) {
+                    mytraffic = ((*worker)->s->transferred/(*worker)->s->lbfactor) +
+                                ((*worker)->s->read/(*worker)->s->lbfactor);
+                    if (!mycandidate || mytraffic < curmin) {
+                        mycandidate = *worker;
+                        curmin = mytraffic;
+                    }
+                }
+            }
+            checked_standby = checking_standby++;
+        }
+        cur_lbset++;
+    } while (cur_lbset <= max_lbset && !mycandidate);
+
+    if (mycandidate) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01210)
+                     "proxy: bytraffic selected worker \"%s\" : busy %" APR_SIZE_T_FMT,
+                     mycandidate->s->name, mycandidate->s->busy);
+
+    }
+
+    return mycandidate;
+}
+
+/* assumed to be mutex protected by caller */
+static apr_status_t reset(proxy_balancer *balancer, server_rec *s) {
+    int i;
+    proxy_worker **worker;
+    worker = (proxy_worker **)balancer->workers->elts;
+    for (i = 0; i < balancer->workers->nelts; i++, worker++) {
+        (*worker)->s->lbstatus = 0;
+        (*worker)->s->busy = 0;
+        (*worker)->s->transferred = 0;
+        (*worker)->s->read = 0;
+    }
+    return APR_SUCCESS;
+}
+
+static apr_status_t age(proxy_balancer *balancer, server_rec *s) {
+        return APR_SUCCESS;
+}
+
+static const proxy_balancer_method bytraffic =
+{
+    "bytraffic",
+    &find_best_bytraffic,
+    NULL,
+    &reset,
+    &age
+};
+
+static void register_hook(apr_pool_t *p)
+{
+    /* Only the mpm_winnt has child init hook handler.
+     * make sure that we are called after the mpm
+     * initializes and after the mod_proxy
+     */
+    ap_register_provider(p, PROXY_LBMETHOD, "bytraffic", "0", &bytraffic);
+}
+
+AP_DECLARE_MODULE(lbmethod_bytraffic) = {
+    STANDARD20_MODULE_STUFF,
+    NULL,       /* create per-directory config structure */
+    NULL,       /* merge per-directory config structures */
+    NULL,       /* create per-server config structure */
+    NULL,       /* merge per-server config structures */
+    NULL,       /* command apr_table_t */
+    register_hook /* register hooks */
+};
diff --git a/modules/proxy/balancers/mod_lbmethod_bytraffic.dsp b/modules/proxy/balancers/mod_lbmethod_bytraffic.dsp
new file mode 100644
index 00000000..3b53fd9c
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_bytraffic.dsp
@@ -0,0 +1,123 @@
+# Microsoft Developer Studio Project File - Name="mod_lbmethod_bytraffic" - Package Owner=<4>
+# Microsoft Developer Studio Generated Build File, Format Version 6.00
+# ** DO NOT EDIT **
+
+# TARGTYPE "Win32 (x86) Dynamic-Link Library" 0x0102
+
+CFG=mod_lbmethod_bytraffic - Win32 Release
+!MESSAGE This is not a valid makefile. To build this project using NMAKE,
+!MESSAGE use the Export Makefile command and run
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_bytraffic.mak".
+!MESSAGE 
+!MESSAGE You can specify a configuration when running NMAKE
+!MESSAGE by defining the macro CFG on the command line. For example:
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_bytraffic.mak" CFG="mod_lbmethod_bytraffic - Win32 Release"
+!MESSAGE 
+!MESSAGE Possible choices for configuration are:
+!MESSAGE 
+!MESSAGE "mod_lbmethod_bytraffic - Win32 Release" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE "mod_lbmethod_bytraffic - Win32 Debug" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE 
+
+# Begin Project
+# PROP AllowPerConfigDependencies 0
+# PROP Scc_ProjName ""
+# PROP Scc_LocalPath ""
+CPP=cl.exe
+MTL=midl.exe
+RSC=rc.exe
+
+!IF  "$(CFG)" == "mod_lbmethod_bytraffic - Win32 Release"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 0
+# PROP BASE Output_Dir "Release"
+# PROP BASE Intermediate_Dir "Release"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 0
+# PROP Output_Dir "Release"
+# PROP Intermediate_Dir "Release"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MD /W3 /O2 /D "WIN32" /D "NDEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MD /W3 /O2 /Oy- /Zi /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "NDEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Release\mod_lbmethod_bytraffic_src" /FD /c
+# ADD BASE MTL /nologo /D "NDEBUG" /win32
+# ADD MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "NDEBUG"
+# ADD RSC /l 0x409 /fo"Release/mod_lbmethod_bytraffic.res" /i "../../../include" /i "../../../srclib/apr/include" /d "NDEBUG" /d BIN_NAME="mod_lbmethod_bytraffic.so" /d LONG_NAME="lbmethod_bytraffic_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /out:".\Release\mod_lbmethod_bytraffic.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bytraffic.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Release\mod_lbmethod_bytraffic.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bytraffic.so /opt:ref
+# Begin Special Build Tool
+TargetPath=.\Release\mod_lbmethod_bytraffic.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ELSEIF  "$(CFG)" == "mod_lbmethod_bytraffic - Win32 Debug"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 1
+# PROP BASE Output_Dir "Debug"
+# PROP BASE Intermediate_Dir "Debug"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 1
+# PROP Output_Dir "Debug"
+# PROP Intermediate_Dir "Debug"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MDd /W3 /EHsc /Zi /Od /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MDd /W3 /EHsc /Zi /Od /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "_DEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Debug\mod_lbmethod_bytraffic_src" /FD /c
+# ADD BASE MTL /nologo /D "_DEBUG" /win32
+# ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "_DEBUG"
+# ADD RSC /l 0x409 /fo"Debug/mod_lbmethod_bytraffic.res" /i "../../../include" /i "../../../srclib/apr/include" /d "_DEBUG" /d BIN_NAME="mod_lbmethod_bytraffic.so" /d LONG_NAME="lbmethod_bytraffic_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_bytraffic.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bytraffic.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_bytraffic.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_bytraffic.so
+# Begin Special Build Tool
+TargetPath=.\Debug\mod_lbmethod_bytraffic.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ENDIF 
+
+# Begin Target
+
+# Name "mod_lbmethod_bytraffic - Win32 Release"
+# Name "mod_lbmethod_bytraffic - Win32 Debug"
+# Begin Group "Source Files"
+
+# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;hpj;bat;for;f90"
+# Begin Source File
+
+SOURCE=.\mod_lbmethod_bytraffic.c
+# End Source File
+# End Group
+# Begin Group "Header Files"
+
+# PROP Default_Filter ".h"
+# Begin Source File
+
+SOURCE=..\mod_proxy.h
+# End Source File
+# End Group
+# Begin Source File
+
+SOURCE=..\..\..\build\win32\httpd.rc
+# End Source File
+# End Target
+# End Project
diff --git a/modules/proxy/balancers/mod_lbmethod_heartbeat.c b/modules/proxy/balancers/mod_lbmethod_heartbeat.c
new file mode 100644
index 00000000..26c81584
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_heartbeat.c
@@ -0,0 +1,464 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mod_proxy.h"
+#include "scoreboard.h"
+#include "ap_mpm.h"
+#include "apr_version.h"
+#include "ap_hooks.h"
+#include "ap_slotmem.h"
+#include "heartbeat.h"
+
+#ifndef LBM_HEARTBEAT_MAX_LASTSEEN
+/* If we haven't seen a heartbeat in the last N seconds, don't count this IP
+ * as allive.
+ */
+#define LBM_HEARTBEAT_MAX_LASTSEEN (10)
+#endif
+
+module AP_MODULE_DECLARE_DATA lbmethod_heartbeat_module;
+
+static int (*ap_proxy_retry_worker_fn)(const char *proxy_function,
+        proxy_worker *worker, server_rec *s) = NULL;
+
+static const ap_slotmem_provider_t *storage = NULL;
+static ap_slotmem_instance_t *hm_serversmem = NULL;
+
+/*
+ * configuration structure
+ * path: path of the file where the heartbeat information is stored.
+ */
+typedef struct lb_hb_ctx_t
+{
+    const char *path;
+} lb_hb_ctx_t;
+
+typedef struct hb_server_t {
+    const char *ip;
+    int busy;
+    int ready;
+    int port;
+    int id;
+    apr_time_t seen;
+    proxy_worker *worker;
+} hb_server_t;
+
+typedef struct ctx_servers {
+    apr_time_t now;
+    apr_hash_t *servers;
+} ctx_servers_t;
+
+static void
+argstr_to_table(apr_pool_t *p, char *str, apr_table_t *parms)
+{
+    char *key;
+    char *value;
+    char *strtok_state;
+
+    key = apr_strtok(str, "&", &strtok_state);
+    while (key) {
+        value = strchr(key, '=');
+        if (value) {
+            *value = '\0';      /* Split the string in two */
+            value++;            /* Skip passed the = */
+        }
+        else {
+            value = "1";
+        }
+        ap_unescape_url(key);
+        ap_unescape_url(value);
+        apr_table_set(parms, key, value);
+        /*
+         ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+         "Found query arg: %s = %s", key, value);
+         */
+        key = apr_strtok(NULL, "&", &strtok_state);
+    }
+}
+
+static apr_status_t readfile_heartbeats(const char *path, apr_hash_t *servers,
+                                    apr_pool_t *pool)
+{
+    apr_finfo_t fi;
+    apr_status_t rv;
+    apr_file_t *fp;
+
+    if (!path) {
+        return APR_SUCCESS;
+    }
+
+    rv = apr_file_open(&fp, path, APR_READ|APR_BINARY|APR_BUFFERED,
+                       APR_OS_DEFAULT, pool);
+
+    if (rv) {
+        return rv;
+    }
+
+    rv = apr_file_info_get(&fi, APR_FINFO_SIZE, fp);
+
+    if (rv) {
+        return rv;
+    }
+
+    {
+        char *t;
+        int lineno = 0;
+        apr_bucket_alloc_t *ba = apr_bucket_alloc_create(pool);
+        apr_bucket_brigade *bb = apr_brigade_create(pool, ba);
+        apr_bucket_brigade *tmpbb = apr_brigade_create(pool, ba);
+        apr_table_t *hbt = apr_table_make(pool, 10);
+
+        apr_brigade_insert_file(bb, fp, 0, fi.size, pool);
+
+        do {
+            hb_server_t *server;
+            char buf[4096];
+            apr_size_t bsize = sizeof(buf);
+            const char *ip;
+
+            apr_brigade_cleanup(tmpbb);
+
+            if (APR_BRIGADE_EMPTY(bb)) {
+                break;
+            }
+
+            rv = apr_brigade_split_line(tmpbb, bb,
+                                        APR_BLOCK_READ, sizeof(buf));
+            lineno++;
+
+            if (rv) {
+                return rv;
+            }
+
+            apr_brigade_flatten(tmpbb, buf, &bsize);
+
+            if (bsize == 0) {
+                break;
+            }
+
+            buf[bsize - 1] = 0;
+
+            /* comment */
+            if (buf[0] == '#') {
+                continue;
+            }
+
+            /* line format: <IP> <query_string>\n */
+            t = strchr(buf, ' ');
+            if (!t) {
+                continue;
+            }
+
+            ip = apr_pstrndup(pool, buf, t - buf);
+            t++;
+
+            server = apr_hash_get(servers, ip, APR_HASH_KEY_STRING);
+
+            if (server == NULL) {
+                server = apr_pcalloc(pool, sizeof(hb_server_t));
+                server->ip = ip;
+                server->port = 80;
+                server->seen = -1;
+
+                apr_hash_set(servers, server->ip, APR_HASH_KEY_STRING, server);
+            }
+
+            apr_table_clear(hbt);
+
+            argstr_to_table(pool, apr_pstrdup(pool, t), hbt);
+
+            if (apr_table_get(hbt, "busy")) {
+                server->busy = atoi(apr_table_get(hbt, "busy"));
+            }
+
+            if (apr_table_get(hbt, "ready")) {
+                server->ready = atoi(apr_table_get(hbt, "ready"));
+            }
+
+            if (apr_table_get(hbt, "lastseen")) {
+                server->seen = atoi(apr_table_get(hbt, "lastseen"));
+            }
+
+            if (apr_table_get(hbt, "port")) {
+                server->port = atoi(apr_table_get(hbt, "port"));
+            }
+
+            if (server->busy == 0 && server->ready != 0) {
+                /* Server has zero threads active, but lots of them ready,
+                 * it likely just started up, so lets /4 the number ready,
+                 * to prevent us from completely flooding it with all new
+                 * requests.
+                 */
+                server->ready = server->ready / 4;
+            }
+
+        } while (1);
+    }
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t hm_read(void* mem, void *data, apr_pool_t *pool)
+{
+    hm_slot_server_t *slotserver = (hm_slot_server_t *) mem;
+    ctx_servers_t *ctx = (ctx_servers_t *) data;
+    apr_hash_t *servers = (apr_hash_t *) ctx->servers;
+    hb_server_t *server = apr_hash_get(servers, slotserver->ip, APR_HASH_KEY_STRING);
+    if (server == NULL) {
+        server = apr_pcalloc(pool, sizeof(hb_server_t));
+        server->ip = apr_pstrdup(pool, slotserver->ip);
+        server->seen = -1;
+
+        apr_hash_set(servers, server->ip, APR_HASH_KEY_STRING, server);
+
+    }
+    server->busy = slotserver->busy;
+    server->ready = slotserver->ready;
+    server->seen = apr_time_sec(ctx->now - slotserver->seen);
+    server->id = slotserver->id;
+    if (server->busy == 0 && server->ready != 0) {
+        server->ready = server->ready / 4;
+    }
+    return APR_SUCCESS;
+}
+static apr_status_t readslot_heartbeats(ctx_servers_t *ctx,
+                                    apr_pool_t *pool)
+{
+    storage->doall(hm_serversmem, hm_read, ctx, pool);
+    return APR_SUCCESS;
+}
+
+
+static apr_status_t read_heartbeats(const char *path, apr_hash_t *servers,
+                                        apr_pool_t *pool)
+{
+    apr_status_t rv;
+    if (hm_serversmem) {
+        ctx_servers_t ctx;
+        ctx.now = apr_time_now();
+        ctx.servers = servers;
+        rv = readslot_heartbeats(&ctx, pool);
+    } else
+        rv = readfile_heartbeats(path, servers, pool);
+    return rv;
+}
+
+static proxy_worker *find_best_hb(proxy_balancer *balancer,
+                                  request_rec *r)
+{
+    apr_status_t rv;
+    int i;
+    apr_uint32_t openslots = 0;
+    proxy_worker **worker;
+    hb_server_t *server;
+    apr_array_header_t *up_servers;
+    proxy_worker *mycandidate = NULL;
+    apr_pool_t *tpool;
+    apr_hash_t *servers;
+
+    lb_hb_ctx_t *ctx =
+        ap_get_module_config(r->server->module_config,
+                             &lbmethod_heartbeat_module);
+
+    if (!ap_proxy_retry_worker_fn) {
+        ap_proxy_retry_worker_fn =
+                APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker);
+        if (!ap_proxy_retry_worker_fn) {
+            /* can only happen if mod_proxy isn't loaded */
+            return NULL;
+        }
+    }
+
+    apr_pool_create(&tpool, r->pool);
+
+    servers = apr_hash_make(tpool);
+
+    rv = read_heartbeats(ctx->path, servers, tpool);
+
+    if (rv) {
+        ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01213)
+                      "lb_heartbeat: Unable to read heartbeats at '%s'",
+                      ctx->path);
+        apr_pool_destroy(tpool);
+        return NULL;
+    }
+
+    up_servers = apr_array_make(tpool, apr_hash_count(servers), sizeof(hb_server_t *));
+
+    for (i = 0; i < balancer->workers->nelts; i++) {
+        worker = &APR_ARRAY_IDX(balancer->workers, i, proxy_worker *);
+        server = apr_hash_get(servers, (*worker)->s->hostname, APR_HASH_KEY_STRING);
+
+        if (!server) {
+            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(01214)
+                      "lb_heartbeat: No server for worker %s", (*worker)->s->name);
+            continue;
+        }
+
+        if (!PROXY_WORKER_IS_USABLE(*worker)) {
+            ap_proxy_retry_worker_fn("BALANCER", *worker, r->server);
+        }
+
+        if (PROXY_WORKER_IS_USABLE(*worker)) {
+            server->worker = *worker;
+            if (server->seen < LBM_HEARTBEAT_MAX_LASTSEEN) {
+                openslots += server->ready;
+                APR_ARRAY_PUSH(up_servers, hb_server_t *) = server;
+            }
+        }
+    }
+
+    if (openslots > 0) {
+        apr_uint32_t c = 0;
+        apr_uint32_t pick = 0;
+
+        pick = ap_random_pick(0, openslots);
+
+        for (i = 0; i < up_servers->nelts; i++) {
+            server = APR_ARRAY_IDX(up_servers, i, hb_server_t *);
+            if (pick >= c && pick <= c + server->ready) {
+                mycandidate = server->worker;
+            }
+
+            c += server->ready;
+        }
+    }
+
+    apr_pool_destroy(tpool);
+
+    return mycandidate;
+}
+
+static apr_status_t reset(proxy_balancer *balancer, server_rec *s) {
+        return APR_SUCCESS;
+}
+
+static apr_status_t age(proxy_balancer *balancer, server_rec *s) {
+        return APR_SUCCESS;
+}
+
+static const proxy_balancer_method heartbeat =
+{
+    "heartbeat",
+    &find_best_hb,
+    NULL,
+    &reset,
+    &age
+};
+
+static int lb_hb_init(apr_pool_t *p, apr_pool_t *plog,
+                          apr_pool_t *ptemp, server_rec *s)
+{
+    apr_size_t size;
+    unsigned int num;
+    lb_hb_ctx_t *ctx = ap_get_module_config(s->module_config,
+                                            &lbmethod_heartbeat_module);
+
+    /* do nothing on first call */
+    if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG)
+        return OK;
+
+    storage = ap_lookup_provider(AP_SLOTMEM_PROVIDER_GROUP, "shm",
+                                 AP_SLOTMEM_PROVIDER_VERSION);
+    if (!storage) {
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, APLOGNO(02281)
+                     "Failed to lookup provider 'shm' for '%s'. Maybe you "
+                     "need to load mod_slotmem_shm?",
+                     AP_SLOTMEM_PROVIDER_GROUP);
+        return OK;
+    }
+
+    /* Try to use a slotmem created by mod_heartmonitor */
+    storage->attach(&hm_serversmem, "mod_heartmonitor", &size, &num, p);
+    if (!hm_serversmem)
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, APLOGNO(02282)
+                     "No slotmem from mod_heartmonitor");
+    else
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, APLOGNO(02283)
+                     "Using slotmem from mod_heartmonitor");
+
+    if (hm_serversmem)
+        ctx->path = "(slotmem)";
+
+    return OK;
+}
+
+static void register_hooks(apr_pool_t *p)
+{
+    static const char * const aszPred[]={ "mod_heartmonitor.c", NULL };
+    ap_register_provider(p, PROXY_LBMETHOD, "heartbeat", "0", &heartbeat);
+    ap_hook_post_config(lb_hb_init, aszPred, NULL, APR_HOOK_MIDDLE);
+}
+
+static void *lb_hb_create_config(apr_pool_t *p, server_rec *s)
+{
+    lb_hb_ctx_t *ctx = (lb_hb_ctx_t *) apr_palloc(p, sizeof(lb_hb_ctx_t));
+
+    ctx->path = ap_server_root_relative(p, "logs/hb.dat");
+
+    return ctx;
+}
+
+static void *lb_hb_merge_config(apr_pool_t *p, void *basev, void *overridesv)
+{
+    lb_hb_ctx_t *ps = apr_pcalloc(p, sizeof(lb_hb_ctx_t));
+    lb_hb_ctx_t *base = (lb_hb_ctx_t *) basev;
+    lb_hb_ctx_t *overrides = (lb_hb_ctx_t *) overridesv;
+
+    if (overrides->path) {
+        ps->path = apr_pstrdup(p, overrides->path);
+    }
+    else {
+        ps->path = apr_pstrdup(p, base->path);
+    }
+
+    return ps;
+}
+
+static const char *cmd_lb_hb_storage(cmd_parms *cmd,
+                                  void *dconf, const char *path)
+{
+    apr_pool_t *p = cmd->pool;
+    lb_hb_ctx_t *ctx =
+    (lb_hb_ctx_t *) ap_get_module_config(cmd->server->module_config,
+                                         &lbmethod_heartbeat_module);
+
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+
+    if (err != NULL) {
+        return err;
+    }
+
+    ctx->path = ap_server_root_relative(p, path);
+
+    return NULL;
+}
+
+static const command_rec cmds[] = {
+    AP_INIT_TAKE1("HeartbeatStorage", cmd_lb_hb_storage, NULL, RSRC_CONF,
+                  "Path to read heartbeat data."),
+    {NULL}
+};
+
+AP_DECLARE_MODULE(lbmethod_heartbeat) = {
+    STANDARD20_MODULE_STUFF,
+    NULL,                       /* create per-directory config structure */
+    NULL,                       /* merge per-directory config structures */
+    lb_hb_create_config,        /* create per-server config structure */
+    lb_hb_merge_config,         /* merge per-server config structures */
+    cmds,                       /* command apr_table_t */
+    register_hooks              /* register hooks */
+};
diff --git a/modules/proxy/balancers/mod_lbmethod_heartbeat.dsp b/modules/proxy/balancers/mod_lbmethod_heartbeat.dsp
new file mode 100644
index 00000000..cb003b09
--- /dev/null
+++ b/modules/proxy/balancers/mod_lbmethod_heartbeat.dsp
@@ -0,0 +1,123 @@
+# Microsoft Developer Studio Project File - Name="mod_lbmethod_heartbeat" - Package Owner=<4>
+# Microsoft Developer Studio Generated Build File, Format Version 6.00
+# ** DO NOT EDIT **
+
+# TARGTYPE "Win32 (x86) Dynamic-Link Library" 0x0102
+
+CFG=mod_lbmethod_heartbeat - Win32 Release
+!MESSAGE This is not a valid makefile. To build this project using NMAKE,
+!MESSAGE use the Export Makefile command and run
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_heartbeat.mak".
+!MESSAGE 
+!MESSAGE You can specify a configuration when running NMAKE
+!MESSAGE by defining the macro CFG on the command line. For example:
+!MESSAGE 
+!MESSAGE NMAKE /f "mod_lbmethod_heartbeat.mak" CFG="mod_lbmethod_heartbeat - Win32 Release"
+!MESSAGE 
+!MESSAGE Possible choices for configuration are:
+!MESSAGE 
+!MESSAGE "mod_lbmethod_heartbeat - Win32 Release" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE "mod_lbmethod_heartbeat - Win32 Debug" (based on "Win32 (x86) Dynamic-Link Library")
+!MESSAGE 
+
+# Begin Project
+# PROP AllowPerConfigDependencies 0
+# PROP Scc_ProjName ""
+# PROP Scc_LocalPath ""
+CPP=cl.exe
+MTL=midl.exe
+RSC=rc.exe
+
+!IF  "$(CFG)" == "mod_lbmethod_heartbeat - Win32 Release"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 0
+# PROP BASE Output_Dir "Release"
+# PROP BASE Intermediate_Dir "Release"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 0
+# PROP Output_Dir "Release"
+# PROP Intermediate_Dir "Release"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MD /W3 /O2 /D "WIN32" /D "NDEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MD /W3 /O2 /Oy- /Zi /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "NDEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Release\mod_lbmethod_heartbeat_src" /FD /c
+# ADD BASE MTL /nologo /D "NDEBUG" /win32
+# ADD MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "NDEBUG"
+# ADD RSC /l 0x409 /fo"Release/mod_lbmethod_heartbeat.res" /i "../../../include" /i "../../../srclib/apr/include" /d "NDEBUG" /d BIN_NAME="mod_lbmethod_heartbeat.so" /d LONG_NAME="lbmethod_heartbeat_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /out:".\Release\mod_lbmethod_heartbeat.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_heartbeat.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Release\mod_lbmethod_heartbeat.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_heartbeat.so /opt:ref
+# Begin Special Build Tool
+TargetPath=.\Release\mod_lbmethod_heartbeat.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ELSEIF  "$(CFG)" == "mod_lbmethod_heartbeat - Win32 Debug"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 1
+# PROP BASE Output_Dir "Debug"
+# PROP BASE Intermediate_Dir "Debug"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 1
+# PROP Output_Dir "Debug"
+# PROP Intermediate_Dir "Debug"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /MDd /W3 /EHsc /Zi /Od /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /FD /c
+# ADD CPP /nologo /MDd /W3 /EHsc /Zi /Od /I ".." /I "../../../include" /I "../../../srclib/apr/include" /I "../../../srclib/apr-util/include" /D "_DEBUG" /D "WIN32" /D "_WINDOWS" /Fd"Debug\mod_lbmethod_heartbeat_src" /FD /c
+# ADD BASE MTL /nologo /D "_DEBUG" /win32
+# ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x809 /d "_DEBUG"
+# ADD RSC /l 0x409 /fo"Debug/mod_lbmethod_heartbeat.res" /i "../../../include" /i "../../../srclib/apr/include" /d "_DEBUG" /d BIN_NAME="mod_lbmethod_heartbeat.so" /d LONG_NAME="lbmethod_heartbeat_module for Apache"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_heartbeat.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_heartbeat.so
+# ADD LINK32 kernel32.lib ws2_32.lib mswsock.lib /nologo /subsystem:windows /dll /incremental:no /debug /out:".\Debug\mod_lbmethod_heartbeat.so" /base:@..\..\..\os\win32\BaseAddr.ref,mod_lbmethod_heartbeat.so
+# Begin Special Build Tool
+TargetPath=.\Debug\mod_lbmethod_heartbeat.so
+SOURCE="$(InputPath)"
+PostBuild_Desc=Embed .manifest
+PostBuild_Cmds=if exist $(TargetPath).manifest mt.exe -manifest $(TargetPath).manifest -outputresource:$(TargetPath);2
+# End Special Build Tool
+
+!ENDIF 
+
+# Begin Target
+
+# Name "mod_lbmethod_heartbeat - Win32 Release"
+# Name "mod_lbmethod_heartbeat - Win32 Debug"
+# Begin Group "Source Files"
+
+# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;hpj;bat;for;f90"
+# Begin Source File
+
+SOURCE=.\mod_lbmethod_heartbeat.c
+# End Source File
+# End Group
+# Begin Group "Header Files"
+
+# PROP Default_Filter ".h"
+# Begin Source File
+
+SOURCE=..\mod_proxy.h
+# End Source File
+# End Group
+# Begin Source File
+
+SOURCE=..\..\..\build\win32\httpd.rc
+# End Source File
+# End Target
+# End Project