Messages in this thread | | | From | Alex Shi <> | Subject | [URGENT rfc patch 0/3] tsc clocksource bug fix | Date | Thu, 4 Jul 2013 13:34:13 +0800 |
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We find some benchmarks drop a lot on tip/sched/core on many Intel boxes, like oltp, tbench, hackbench etc. and bisected the commit 5d33b883ae cause this regression. Due to this commit, the clocksource was changed to hpet from tsc even tsc will be set CLOCK_SOURCE_VALID_FOR_HRES later in clocksource_watchdog.
Tim Chen said the hpet reading cost much. That cause this regression.
This patchset fixed this bug by re-select clocksource after this flag set on tsc.
BTW, If the tsc is marked as constant and nonstop, could we set it as system clocksource when do tsc register? w/o checking it on clocksource_watchdog?
regards! Alex
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