path: root/usr/src/man/man1/madv.so.1.1

'\" te
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.TH MADV.SO.1 1 "Feb 15, 2002"
.SH NAME
madv.so.1 \- madv library
.SH SYNOPSIS
.LP
.nf
\fB/usr/lib/madv.so.1\fR
.fi

.SH DESCRIPTION
.sp
.LP
The \fBmadv.so.1\fR shared object provides a means by which the VM advice can
be selectively configured for a launched process (or processes) and its
descendants. To enable \fBmadv.so.1\fR, the following string needs to be
present in the environment (see \fBld.so.1\fR(1)) along with one or more
\fBMADV\fR environment variables:
.sp
.in +2
.nf
\fBLD_PRELOAD=$LD_PRELOAD:madv.so.1\fR
.fi
.in -2
.sp

.SH ENVIRONMENT VARIABLES
.sp
.LP
If the \fBmadv.so.1\fR shared object is specified in the \fBLD_PRELOAD\fR list,
the following environment variables are read by the \fBmadv\fR shared object to
determine to which created process(es) to apply the specified advice.
.sp
.ne 2
.na
\fB\fBMADV\fR=\fIadvice\fR \fR
.ad
.RS 27n
\fBMADV\fR specifies the VM advice to use for all heap, shared memory, and mmap
regions in the process address                 space. This advice is applied to
all created processes.
.sp
Values for \fIadvice\fR correspond to values in <sys/mman.h> used in
\fBmadvise\fR(3C) to specify memory access patterns:
.br
.in +2
normal
.in -2
.br
.in +2
random
.in -2
.br
.in +2
sequential
.in -2
.br
.in +2
access_lwp
.in -2
.br
.in +2
access_many
.in -2
.br
.in +2
access_default
.in -2
.RE

.sp
.ne 2
.na
\fB\fBMADVCFGFILE\fR=\fIconfig-file\fR\fR
.ad
.RS 27n
\fIconfig-file\fR is a text file which contains one or more \fBmadv\fR
configuration entries of the form:
.sp
.in +2
.nf
\fIexec-name\fR \fIexec-args\fR:\fIadvice-opts\fR
.fi
.in -2
.sp

Advice specified in \fIconfig-file\fR takes precedence over that specified by
the \fBMADV\fR environment variable. When \fBMADVCFGFILE\fR is not set, advice
is taken from file \fB/etc/madv.conf\fR if it exists.
.sp
\fIexec-name\fR specifies the name of an application or executable. The
corresponding advice is set for newly created processes (see
\fBgetexecname\fR(3C)) that match the first \fIexec-name\fR found in the file.
.sp
\fIexec-name\fR can be a full pathname, a base name, or a pattern string. See
\fBFile Name Generation\fR in \fBsh\fR(1) for a discussion of pattern matching.
.sp
\fIexec-args\fR is an optionally specified pattern string to match against
arguments. Advice is set only if \fIexec-args\fR is not specified or occurs
within the arguments to \fIexec-name\fR.
.sp
\fIadvice-opts\fR is a comma-separated list specifying the advice for various
memory region(s):
.sp
.ne 2
.na
\fB\fBmadv\fR=\fIadvice\fR\fR
.ad
.RS 21n
Applies to all heap, shared memory, and mmap regions in the process address
space.
.RE

.sp
.ne 2
.na
\fB\fBheap\fR=\fIadvice\fR\fR
.ad
.RS 21n
The heap is defined to be the brk area (see \fBbrk\fR(2)). Applies to the
existing heap and for any additional heap memory allocated in the future.
.RE

.sp
.ne 2
.na
\fB\fBshm\fR=\fIadvice\fR\fR
.ad
.br
.na
\fB\fBism\fR=\fIadvice\fR\fR
.ad
.br
.na
\fB\fBdism\fR=\fIadvice\fR\fR
.ad
.RS 21n
Shared memory segments (see \fBshmat\fR(2)) attached using any flags, flag
\fBSHM_SHARE_MMU\fR, or flag \fBSHM_PAGEABLE\fR  respectively. Options
\fBism\fR and \fBdism\fR take precedence over option \fBshm\fR.
.RE

.sp
.ne 2
.na
\fB\fBmap\fR=\fIadvice\fR\fR
.ad
.br
.na
\fB\fBmapshared\fR=\fIadvice\fR\fR
.ad
.br
.na
\fB\fBmapprivate\fR=\fIadvice\fR\fR
.ad
.br
.na
\fB\fBmapanon\fR=\fIadvice\fR\fR
.ad
.RS 21n
Mappings established through \fBmmap\fR(2) using any flags, flag
\fBMAP_SHARED\fR, flag \fBMAP_PRIVATE\fR, or flag \fBMAP_ANON\fR, respectively.
Options \fBmapshared\fR, \fBmapprivate\fR, and \fBmapanon\fR take precedence
over option \fBmap\fR. Option \fBmapanon\fR takes precedence over
\fBmapshared\fR and \fBmapprivate\fR.
.RE

.RE

.sp
.ne 2
.na
\fB\fBMADVERRFILE\fR=\fIpathname\fR\fR
.ad
.RS 27n
By default, error messages are logged via \fBsyslog\fR(3C) using level
\fBLOG_ERR\fR and facility \fBLOG_USER\fR. If \fBMADVERRFILE\fR contains a
valid \fIpathname\fR (such as \fB/dev/stderr\fR), error messages will be logged
there instead.
.RE

.SH EXAMPLES
.LP
\fBExample 1 \fRApplying advice to all ISM segments
.sp
.LP
The following configuration applies advice to all ISM segments for application
\fB/usr/bin/foo\fR:

.sp
.in +2
.nf
example$ \fBLD_PRELOAD=$LD_PRELOAD:madv.so.1\fR
example$ \fBMADVCFGFILE=madvcfg\fR
example$ \fBexport LD_PRELOAD MADVCFGFILE\fR
example$ \fBcat $MADVCFGFILE\fR
    /usr/bin/foo:ism=access_lwp
.fi
.in -2
.sp

.LP
\fBExample 2 \fRSetting advice for all applications with exception
.sp
.LP
The following configuration sets advice for all applications with the exception
of \fBls\fR.

.sp
.in +2
.nf
example$ \fBLD_PRELOAD=$LD_PRELOAD:madv.so.1\fR
example$ \fBMADV=access_many\fR
example$ \fBMADVCFGFILE=madvcfg\fR
example$ \fBexport LD_PRELOAD MADV MADVCFGFILE\fR
example$ \fBcat $MADVCFGFILE\fR
    ls:
.fi
.in -2
.sp

.LP
\fBExample 3 \fRPrecedence rules (continuation from Example 2)
.sp
.LP
Because \fBMADVCFGFILE\fR takes precedence over \fBMADV\fR,
specifying '\fB*\fR' (pattern match all) for the \fIexec-name\fR of the last \fBmadv\fR
configuration entry would be equivalent to setting \fBMADV\fR. The following is
equivalent to example 2:

.sp
.in +2
.nf
example$ \fBLD_PRELOAD=$LD_PRELOAD:madv.so.1\fR
example$ \fBMADVCFGFILE=madvcfg\fR
example$ \fBexport LD_PRELOAD MADVCFGFILE\fR
example$ \fBcat $MADVCFGFILE\fR
    ls:
    *:madv=access_many
.fi
.in -2
.sp

.LP
\fBExample 4 \fRApplying advice for different regions
.sp
.LP
The following configuration applies one type of advice for mmap regions and
different advice for heap and shared memory regions for a select set of
applications with exec names that begin with \fBfoo\fR:

.sp
.in +2
.nf
example$ \fBLD_PRELOAD=$LD_PRELOAD:madv.so.1\fR
example$ \fBMADVCFGFILE=madvcfg\fR
example$ \fBexport LD_PRELOAD MADVCFGFILE\fR
example$ \fBcat $MADVCFGFILE\fR
    foo*:madv=access_many,heap=sequential,shm=access_lwp
.fi
.in -2
.sp

.LP
\fBExample 5 \fRApplying advice selectively
.sp
.LP
The following configuration applies advice for the heap of applications
beginning with \fBora\fR that have \fBora1\fR as an argument:

.sp
.in +2
.nf
example$ \fBLD_PRELOAD=$LD_PRELOAD:madv.so.1\fR
example$ \fBMADVCFGFILE=madvcfg\fR
example$ \fBexport LD_PRELOAD MADVCFGFILE\fR
example$ \fBcat $MADVCFGFILE\fR
    ora* ora1:heap=access_many
.fi
.in -2
.sp

.SH FILES
.sp
.ne 2
.na
\fB\fB/etc/madv.conf\fR \fR
.ad
.RS 19n
Configuration file
.RE

.SH SEE ALSO
.sp
.LP
\fBcat\fR(1), \fBld.so.1\fR(1), \fBproc\fR(1), \fBsh\fR(1), \fBbrk\fR(2),
\fBexec\fR(2), \fBfork\fR(2), \fBmmap\fR(2), \fBmemcntl\fR(2), \fBshmat\fR(2),
\fBgetexecname\fR(3C), \fBmadvise\fR(3C), \fBsyslog\fR(3C), \fBproc\fR(4),
\fBattributes\fR(5)
.SH NOTES
.sp
.LP
The advice is inherited. A child process has the same advice         as its
parent. On \fBexec()\fR (see \fBexec\fR(2)), the advice is set back to the
default system advice unless different advice has been configured via the
\fBmadv\fR shared object.
.sp
.LP
Advice is only applied to \fBmmap\fR regions explicitly created by the user
program. Those regions established by the run-time linker or by system
libraries making direct system calls (for example, libthread allocations for
thread stacks) are not affected.