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由 Eric Dumazet 提交于
Commit def0a9b2 (sched_clock: Make it NMI safe) assumed cmpxchg() of 64bit values was available on X86_32. That is not so - and causes some subtle scheduler misbehavior due to incorrect timestamps off to up by ~4 seconds. Two symptoms are known right now: - interactivity problems seen by Arjan: up to 600 msecs latencies instead of the expected 20-40 msecs. These latencies are very visible on the desktop. - incorrect CPU stats: occasionally too high percentages in 'top', and crazy CPU usage stats. Reported-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Cc: John Stultz <johnstul@us.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090930170754.0886ff2e@infradead.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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