diff options
author | Len Brown <len.brown@intel.com> | 2010-05-24 14:27:44 -0400 |
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committer | Len Brown <len.brown@intel.com> | 2010-05-28 13:58:57 -0400 |
commit | 02cf4f9808382af7265cafc33dc86ec5875526aa (patch) | |
tree | 6e4b7fc98a125e6af6011ee04e5fbf2d2fe38c4f /fs/proc/stat.c | |
parent | a7d27c37533524e23bbdc9ba1d78e3241b7483ea (diff) |
ACPI: acpi_idle: touch TS_POLLING only in the non-MWAIT case
commit d306ebc28649b89877a22158fe0076f06cc46f60
(ACPI: Be in TS_POLLING state during mwait based C-state entry)
fixed an important power & performance issue where ACPI c2 and c3 C-states
were clearing TS_POLLING even when using MWAIT (ACPI_STATE_FFH).
That bug had been causing us to receive redundant scheduling interrups
when we had already been woken up by MONITOR/MWAIT.
Following up on that...
In the MWAIT case, we don't have to subsequently
check need_resched(), as that c heck was there
for the TS_POLLING-clearing case.
Note that not only does the cpuidle calling function
already check need_resched() before calling us, the
low-level entry into monitor/mwait calls it twice --
guaranteeing that a write to the trigger address
can not go un-noticed.
Also, in this case, we don't have to set TS_POLLING
when we wake, because we never cleared it.
Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Venkatesh Pallipadi <venki@google.com>
Diffstat (limited to 'fs/proc/stat.c')
0 files changed, 0 insertions, 0 deletions