* Lan Tianyu <[email protected]> wrote:
> On 2014年08月26日 15:43, 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.
> > 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.
> >
> > Borislav and Prarit also helped to test the patch on an AMD machine and
> > a few systems of various sizes and configurations (multi-socket,
> > single-socket, no hyper threading, etc.). No issues seen.
> >
> > Acked-by: Borislav Petkov <[email protected]>
> > Tested-by: Prarit Bhargava <[email protected]>
> > Signed-off-by: Lan Tianyu <[email protected]>
> > ---
> > arch/x86/kernel/smpboot.c | 23 +++++++++++------------
> > 1 file changed, 11 insertions(+), 12 deletions(-)
> >
>
> Hi HPA, Ingo, Thomas & Peter Z:
> Is this patch ok for you?
Nice patch!
I cleaned up a few small details and will push it out if it
passes testing.
Thanks,
Ingo
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