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| author | Shesha Sreenivasamurthy <Shesha.Sreenivasamurthy@Sun.COM> | 2009-06-03 10:15:31 -0700 |
|---|---|---|
| committer | Shesha Sreenivasamurthy <Shesha.Sreenivasamurthy@Sun.COM> | 2009-06-03 10:15:31 -0700 |
| commit | 050fa54035f294ec6c58427086e7635a70d94e07 (patch) | |
| tree | 772a8e4e54d478151e6ce4ed1a16e7e65fbd4218 /usr/src | |
| parent | 8afffe5e8965958d2c3dc203d9821fb08c33ffb6 (diff) | |
| download | illumos-joyent-050fa54035f294ec6c58427086e7635a70d94e07.tar.gz | |
6833717 cpu_smt_pause needs tuning for Rock
Diffstat (limited to 'usr/src')
| -rw-r--r-- | usr/src/uts/sun4v/cpu/rock_asm.s | 51 |
1 files changed, 24 insertions, 27 deletions
diff --git a/usr/src/uts/sun4v/cpu/rock_asm.s b/usr/src/uts/sun4v/cpu/rock_asm.s index b78652b3f3..f9b1c94894 100644 --- a/usr/src/uts/sun4v/cpu/rock_asm.s +++ b/usr/src/uts/sun4v/cpu/rock_asm.s @@ -20,7 +20,7 @@ */ /* - * Copyright 2008 Sun Microsystems, Inc. All rights reserved. + * Copyright 2009 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ @@ -32,23 +32,8 @@ #include <sys/fsr.h> /* FPRS_FEF, FPRS_DU */ #include <vm/hat_sfmmu.h> /* TSBTAG_INVALID */ -#define TRANS_RETRY_COUNT 3 - -/* - * XXX Delete this comment and these #undef's when the corresponding - * Makefile.workarounds lines are deleted. - * XXX - * - * Transactional instructions are used here regardless of what's in - * Makefile.workarounds. - */ -#undef chkpt -#undef commit - - #if defined(lint) - -#include <sys/mutex.h> +#include <sys/types.h> void cpu_smt_pause(void) @@ -131,22 +116,34 @@ cpu_inv_tsb(caddr_t tsb_base, uint_t tsb_bytes) #else /* lint */ -/* XXX TODO XXX - * When we get real hardware, we need to do performance tuning on this. - * Does it help? Does it ever hurt? How many membar's should we have here? +/* + * Called from various spin loops to prevent this strand from + * stealing too many cycles from its sibling, who is presumably + * doing useful work. + * + * With a 2.1 GHz clock, 100 membar #Halt instructions plus + * the call/return overhead will take approximately 500 nanoseconds. + * That is a suitable time for a PAUSE, as it is roughly equal to + * two memory accesses. */ - /* - * Called from various spin loops to prevent this strand from - * stealing too many cycles from its sibling, who is presumably - * doing useful work. - */ ENTRY_NP(cpu_smt_pause) + mov 10, %o0 +1: membar #Halt + membar #Halt + membar #Halt + membar #Halt + membar #Halt + membar #Halt + membar #Halt + membar #Halt + membar #Halt + subcc %o0, 1, %o0 + bg,pt %xcc, 1b membar #Halt retl - nop + membar #Halt SET_SIZE(cpu_smt_pause) - /* * fp_zero() - clear all fp data registers and the fsr */ |