Messages in this thread | | | Date | Tue, 12 Aug 2014 09:55:41 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH V2] X86/CPU: Avoid 100ms sleep for cpu offline during S3 |
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On Tue, Aug 12, 2014 at 03:31:06PM +0800, Lan Tianyu wrote: > With some bad kernel configures, cpu offline consumes more than 100ms > during S3. This because native_cpu_die() would fall into 100ms > sleep when cpu idle loop thread marked cpu state to DEAD slower. It's > timing related issue. What native_cpu_die() does is that poll cpu > state and wait for 100ms if cpu state hasn't been marked to DEAD. > The 100ms sleep doesn't make sense. To avoid such long sleep, this > patch is to add struct completion to each cpu, wait for the completion > in the native_cpu_die() and wakeup the completion when the cpu state is > marked to DEAD. > > Tested on the Intel Xeon server with 48 cores, Ivbridge and Haswell laptops.
... and on an AMD laptop.
> the times of cpu offline on these machines are reduced from more than 100ms > to less than 5ms. The system suspend time reduces 2.3s on the servers. > > Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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