Re: [PATCH]x86-x86_64 flush cache for CPU hotplug

Shaohua Li
2005-06-13T01:06:09Z

On Fri, 2005-06-10 at 19:21 +0200, Andi Kleen wrote:
> On Fri, Jun 10, 2005 at 11:30:08AM +0800, Shaohua Li wrote:
> > Hi,
> > We should flush cache at CPU hotplug. An error has been observed data is
> > corrupted after CPU hotplug in CPUs with bigger cache.
>
> Did you see that with actual hardware CPU hotplug? With software
> for testing only hotplug it should not make any difference.
Sure, this should only occur on physical CPU hotplug. I haven't hardware
which supports physical CPU hotplug. What I'm testing is supend-to-ram.
In this case, we offline all APs and BIOS possibly will put APs into
some special states (maybe reboot APs). It's very like physical CPU
hotplug.

> If you have a targetted test that causes the corruption that would be great
> so we can add to our stress test senarios.
No, I haven't. IA64 doesn't support suspend/resume, so my test case
can't apply to IA64.

Thanks,
Shaohua