| commit | 54b663bdc94f94bf4d77566ec42d30d22b68ff8f | |
| author | Pallipadi, Venkatesh <venkatesh.pallipadi@intel.com> | |
| Wed, 10 Feb 2010 18:35:31 +0000 (10 10:35 -0800) | ||
| committer | Greg Kroah-Hartman <gregkh@suse.de> | |
| Thu, 1 Apr 2010 22:55:53 +0000 (1 15:55 -0700) | ||
| tree | efe5b156114738cdeb3138f68c4a9fdaf9eb6719 | treesnapshot (tar.gz zip) |
| parent | 354a8d03e60a13600346babc1a78ecce4075f917 | commitdiff |
ACPI: Be in TS_POLLING state during mwait based C-state entry
commit d306ebc28649b89877a22158fe0076f06cc46f60 upstream.
ACPI deep C-state entry had a long standing bug/missing feature, wherein we were sending
resched IPIs when an idle CPU is in mwait based deep C-state. Only mwait based C1 was using
the write to the monitored address to wake up mwait'ing CPU.
This patch changes the code to retain TS_POLLING bit if we are entering an mwait based
deep C-state.
The patch has been verified to reduce the number of resched IPIs in general and also
improves the performance/power on workloads with low system utilization (i.e., when mwait based
deep C-states are being used).
Fixes "netperf ~50% regression with 2.6.33-rc1, bisect to 1b9508f"
http://marc.info/?l=linux-kernel&m=126441481427331&w=4
Reported-by: Lin Ming <ming.m.lin@intel.com>
Tested-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit d306ebc28649b89877a22158fe0076f06cc46f60 upstream.
ACPI deep C-state entry had a long standing bug/missing feature, wherein we were sending
resched IPIs when an idle CPU is in mwait based deep C-state. Only mwait based C1 was using
the write to the monitored address to wake up mwait'ing CPU.
This patch changes the code to retain TS_POLLING bit if we are entering an mwait based
deep C-state.
The patch has been verified to reduce the number of resched IPIs in general and also
improves the performance/power on workloads with low system utilization (i.e., when mwait based
deep C-states are being used).
Fixes "netperf ~50% regression with 2.6.33-rc1, bisect to 1b9508f"
http://marc.info/?l=linux-kernel&m=126441481427331&w=4
Reported-by: Lin Ming <ming.m.lin@intel.com>
Tested-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| drivers/acpi/processor_idle.c | diffblobblamehistory |