From: Cliff Wickman <cpw@sgi.com>
To: Petr Holasek <pholasek@redhat.com>
Cc: Jon Stanley <jonstanley@gmail.com>,
Andi Kleen <andi@firstfloor.org>,
linux-numa@vger.kernel.org
Subject: Re: numactl using it's own affinity to determine CPU set
Date: Tue, 23 Oct 2012 09:19:18 -0500 [thread overview]
Message-ID: <20121023141918.GA27082@sgi.com> (raw)
In-Reply-To: <20121023122139.GA5766@machinehead.brq.redhat.com>
Hi Petr,
On Tue, Oct 23, 2012 at 02:21:40PM +0200, Petr Holasek wrote:
> Hi everyone,
>
> On Mon, 22 Oct 2012, Jon Stanley wrote:
> > On Mon, Oct 22, 2012 at 3:41 PM, Andi Kleen <andi@firstfloor.org> wrote:
> > > That was done intentional at some point to handle cpusets.
> > > numactl 1.0 or so didn't have that problem.
> >
> > I'll happily admit to not being an expert here :)
>
> I've added new interface for parsing cpusets/nodesets with _all() suffix
> in 2.0.8-rc5 libnuma, but numactl utility still uses old ones with cpuset
> awareness. I didn't want to dig into some libnuma internals and change
> behaviour of dependent utils in such way.
>
> >
> > However, I thought that the concept of cpusets was that if you
> > attempted to set affinity outside of your cpuset, that would silently
> > fail. I assume that the reason that libnuma didn't want to set outside
> > of it's own affinity mask is to avoid such a silent failure?
> >
> > Also, I question the Real World(TM) prevalence of cpusets.
> >
> > > However it's unclear if it's really bug.
> >
> > Not sure if I'd call it a bug since it was intentional, but sure would
> > call it an unexpected change in behavior :)
>
> I like the idea of some overriding option proposed by Andi.
>
> btw, Cliff, can you remember what was the reason for this change in some
> version after 1.0?
>
> Petr
Memory nodes allowed was made cpuset-aware by the below patch.
I'm not quite sure if this is the change you are asking about.
patch 0804_ls_patch2
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
Date: Wed, 02 Apr 2008 14:34:37 -0400
Depends-on: MPOL_F_MEMS_ALLOWED kernel patch
Provide libnuma API for MPOL_F_MEMS_ALLOWED flag.
Return nodes allowed by the application's current cpuset context
via new API numa_get_mems_allowed().
+.BR numa_get_mems_allowed()
+returns the mask of nodes from which the process is allowed to allocate
+memory in it's current cpuset context.
-Cliff
--
Cliff Wickman
SGI
cpw@sgi.com
(651) 683-3824
next prev parent reply other threads:[~2012-10-23 14:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 19:35 numactl using it's own affinity to determine CPU set Jon Stanley
2012-10-22 19:41 ` Andi Kleen
2012-10-22 20:12 ` Jon Stanley
2012-10-23 12:21 ` Petr Holasek
2012-10-23 14:19 ` Cliff Wickman [this message]
2012-10-23 21:17 ` Petr Holasek
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