[Users] nginx, inside openvz CT, worker_cpu_affinity

[Solar Designer]

On Tue, Jul 31, 2012 at 12:52:56PM +0400, Andrey Vagin wrote:
> Here is an answer from Vladimir Davydov, who maintains scheduler in
> vzkernel.
> 
> On Tue, Jul 31, 2012 at 10:29:43AM +0400, Vladimir Davydov wrote:
> > http://nginx.org/en/docs/ngx_core_module.html#worker_cpu_affinity
> >  >
> >  > worker_processes    4;
> >  > worker_cpu_affinity 0001 0010 0100 1000;
> >  >
> >  > "Binds worker processes to the sets of CPUs."
> > > Does it make sense inside OpenVZ container?
> > 
> > It never works. CPU affinity masks are ignored inside containers.

I don't know about nginx in particular, but CPU affinity masks certainly
work for me in OpenVZ containers, at least on RHEL5'ish kernels.  I've
just re-tested on this one:

$ uname -mrs
Linux 2.6.18-308.4.1.el5.028stab100.2.owl1 x86_64

Specifically, sched_setaffinity() in custom code (custom patch to Apache's
suEXEC) and libgomp's GOMP_CPU_AFFINITY env var both work just fine.

Vladimir - does your comment apply to some other kernel versions?
RHEL6'ish maybe?  It'd be good to know and be prepared... and it'd be
really unfortunate to lose this functionality when we finally move to
RHEL6'ish kernels (soonish).

Thanks,

Alexander