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author | Ingo Molnar <mingo@elte.hu> | 2008-11-08 10:19:55 -0500 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-11-08 10:48:19 -0500 |
commit | 0d12cdd5f883f508d33b85c1bae98fa28987c8c7 (patch) | |
tree | e07bb1f9ef49062fbd9817fe41cab66964bedf03 /arch/s390 | |
parent | 52c642f33b14bfa1b00ef2b68296effb34a573f3 (diff) |
sched: improve sched_clock() performance
in scheduler-intense workloads native_read_tsc() overhead accounts for
20% of the system overhead:
659567 system_call 41222.9375
686796 schedule 435.7843
718382 __switch_to 665.1685
823875 switch_mm 4526.7857
1883122 native_read_tsc 55385.9412
9761990 total 2.8468
this is large part due to the rdtsc_barrier() that is done before
and after reading the TSC.
But sched_clock() is not a precise clock in the GTOD sense, using such
barriers is completely pointless. So remove the barriers and only use
them in vget_cycles().
This improves lat_ctx performance by about 5%.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/s390')
0 files changed, 0 insertions, 0 deletions