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authorscottl <scottl@FreeBSD.org>2004-07-18 15:59:03 +0000
committerscottl <scottl@FreeBSD.org>2004-07-18 15:59:03 +0000
commit7ad60316cd2a6fab33bff1ecd701c1d696895b96 (patch)
treeac22ab2a20ec2a247773c0b4fbd9fd368f767eb2 /sys/conf
parentcf328c10576453a3e63ec1ff22f92f1b352db615 (diff)
downloadFreeBSD-src-7ad60316cd2a6fab33bff1ecd701c1d696895b96.zip
FreeBSD-src-7ad60316cd2a6fab33bff1ecd701c1d696895b96.tar.gz
Enable ADAPTIVE_MUTEXES by default by changing the sense of the option to
NO_ADAPTIVE_MUTEXES. This option has been enabled by default on amd64 for quite some time, and has been extensively tested on i386 and sparc64. It shows measurable performance gains in many circumstances, and few negative effects. It would be nice in t he future if adaptive mutexes actually went to sleep after a certain amount of spinning, but that will require quite a bit more testing.
Diffstat (limited to 'sys/conf')
-rw-r--r--sys/conf/NOTES5
-rw-r--r--sys/conf/options2
2 files changed, 4 insertions, 3 deletions
diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 0ec51a5..6e33605 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -169,8 +169,9 @@ options SMP # Symmetric MultiProcessor Kernel
# ADAPTIVE_MUTEXES changes the behavior of blocking mutexes to spin
# if the thread that currently owns the mutex is executing on another
-# CPU.
-options ADAPTIVE_MUTEXES
+# CPU. This behaviour is enabled by default, so this option can be used
+# to disable it.
+options NO_ADAPTIVE_MUTEXES
# MUTEX_NOINLINE forces mutex operations to call functions to perform each
# operation rather than inlining the simple cases. This can be used to
diff --git a/sys/conf/options b/sys/conf/options
index 042a025..d1dcb2a 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -56,7 +56,7 @@ KDB_TRACE opt_kdb.h
KDB_UNATTENDED opt_kdb.h
# Miscellaneous options.
-ADAPTIVE_MUTEXES
+NO_ADAPTIVE_MUTEXES
ALQ
CODA_COMPAT_5 opt_coda.h
COMPAT_43 opt_compat.h
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