Author: adrian
Date: Mon Apr 27 19:18:51 2015
New Revision: 282110
URL: https://svnweb.freebsd.org/changeset/base/282110
Log:
Drop the default for performance_cx_lowest (ie, what to use when AC is
connected) to ACPI C2.
ACPI C3 ends up doing a lot more work before entering sleep, some of which
requires grabbing a global ACPI hardware serialising mutex.
Because of this, the more CPU cores you have, the more that lock contends
under load, reaching close to the #1 lock contention (after VM, which is being
worked on.)
Tested:
* Sandy bridge Xeon, 2 socket * 8 core
* Ivy bridge Xeon v2, 2 socket * 8 core
* Westmere-EX, 4 socket * 10 core
* Ivybridge desktop
* Sandybridge mobile
* Ivybridge mobile
MFC after: 2 weeks
Modified:
head/etc/defaults/rc.conf
Modified: head/etc/defaults/rc.conf
==============================================================================
--- head/etc/defaults/rc.conf Mon Apr 27 18:41:31 2015 (r282109)
+++ head/etc/defaults/rc.conf Mon Apr 27 19:18:51 2015 (r282110)
@@ -648,7 +648,7 @@ devfs_system_ruleset="" # The name (NOT
devfs_set_rulesets="" # A list of /mount/dev=ruleset_name settings to
# apply (must be mounted already, i.e. fstab(5))
devfs_load_rulesets="YES" # Enable to always load the default rulesets
-performance_cx_lowest="Cmax" # Online CPU idle state
+performance_cx_lowest="C2" # Online CPU idle state
performance_cpu_freq="NONE" # Online CPU frequency
economy_cx_lowest="Cmax" # Offline CPU idle state
economy_cpu_freq="NONE" # Offline CPU frequency
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