Unexpected warning on non-NUMA host

Unexpected warning on non-NUMA host

[Kazunori Asayama]

Hi all,

When I ran a program which was linked with libnuma (version 2.0.2) but
without libnuma function calls on non-NUMA platform, I got an unexpected
warning message:

> libnuma: Warning: /sys not mounted or no numa system. Assuming one
node: No such file or directory

I'd like to create single program which works on both of NUMA and
non-NUMA platforms, by switching behavior according to the result of
numa_available(). So I expect the message above isn't displayed if no
NUMA library function except numa_available() is called, even if the
program is linked with libnuma.

AFAIK, the version 1 didn't show such message until a NUMA function
except numa_available() was called.

So is the current behavior unexpected?

Regards,
-- 
(ASAYAMA Kazunori
  (asayama@sm.sony.co.jp))
t

Re: Unexpected warning on non-NUMA host

[Cliff Wickman]

Asayama,

On Fri, Jan 09, 2009 at 09:23:09PM +0900, Kazunori Asayama wrote:
> Hi all,
> 
> When I ran a program which was linked with libnuma (version 2.0.2) but
> without libnuma function calls on non-NUMA platform, I got an unexpected
> warning message:
> 
> > libnuma: Warning: /sys not mounted or no numa system. Assuming one
> node: No such file or directory
> 
> I'd like to create single program which works on both of NUMA and
> non-NUMA platforms, by switching behavior according to the result of
> numa_available(). So I expect the message above isn't displayed if no
> NUMA library function except numa_available() is called, even if the
> program is linked with libnuma.
> 
> AFAIK, the version 1 didn't show such message until a NUMA function
> except numa_available() was called.
> 
> So is the current behavior unexpected?

libnuma's initialization attempts determine the size of everything
(configured nodes, nodemask size, max cpus, configured cpus, cpu
and node constraints of the current thread)
 
In doing so, it emits the warning you see if it cannot open
/sys/devices/system/node.
It sets  maxconfigurednode = 0
Perhaps it shouldn't complain, but just go on quietly to avoid
the noise on a non-NUMA platform.

Any objection?

-Cliff
-- 
Cliff Wickman
Silicon Graphics, Inc.
cpw@sgi.com
(651) 683-3824

Re: Unexpected warning on non-NUMA host

[Kazunori Asayama]

Cliff,

Cliff Wickman wrote:
> In doing so, it emits the warning you see if it cannot open
> /sys/devices/system/node.
> It sets  maxconfigurednode = 0
> Perhaps it shouldn't complain, but just go on quietly to avoid
> the noise on a non-NUMA platform.
> 
> Any objection?

Sounds good for me.

Thanks,
-- 
(Kazunori Asayama
  (asayama@sm.sony.co.jp))
t

Re: Unexpected warning on non-NUMA host

[Cliff Wickman]

On Tue, Jan 13, 2009 at 10:57:53AM +0900, Kazunori Asayama wrote:
> Cliff,
> 
> Cliff Wickman wrote:
> > In doing so, it emits the warning you see if it cannot open
> > /sys/devices/system/node.
> > It sets  maxconfigurednode = 0
> > Perhaps it shouldn't complain, but just go on quietly to avoid
> > the noise on a non-NUMA platform.
> > 
> > Any objection?
> 
> Sounds good for me.

That change is in the numactl-2.0.3-rc1.tar.gz

There will be more changes soon, as Andi and Bernhard have posted some
patches that I haven't gotten to yet.

-Cliff
-- 
Cliff Wickman
Silicon Graphics, Inc.
cpw@sgi.com
(651) 683-3824