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| author | Pallipadi, Venkatesh <[email protected]> | 2010-02-10 18:35:31 +0000 |
|---|---|---|
| committer | Len Brown <[email protected]> | 2010-02-22 18:10:14 +0000 |
| commit | d306ebc28649b89877a22158fe0076f06cc46f60 (patch) | |
| tree | 9a054d9a01889acca64bf018ed1e4778db0d5e19 /lib/debugobjects.c | |
| parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dto... (diff) | |
| download | kernel-d306ebc28649b89877a22158fe0076f06cc46f60.tar.gz kernel-d306ebc28649b89877a22158fe0076f06cc46f60.zip | |
ACPI: Be in TS_POLLING state during mwait based C-state entry
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 <[email protected]>
Tested-by: Alex Shi <[email protected]>
Signed-off-by: Venkatesh Pallipadi <[email protected]>
Signed-off-by: Len Brown <[email protected]>
Diffstat (limited to 'lib/debugobjects.c')
0 files changed, 0 insertions, 0 deletions