Messages in this thread | | | Date | Wed, 24 Sep 2014 15:00:19 +0200 | From | Ingo Molnar <> | Subject | Re: [Resend PATCH V2] X86/CPU: Avoid 100ms sleep for cpu offline during S3 |
| |
* Lan Tianyu <tianyu.lan@intel.com> 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 <bp@suse.de> > > Tested-by: Prarit Bhargava <prarit@redhat.com> > > Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> > > --- > > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |