[procps] Re: top: NUMA node CPU utilization support
- From: Jim Warner <james.warner@xxxxxxxxxxx>
- To: procps@xxxxxxxxxxxxx
- Date: Thu, 11 Apr 2013 10:47:26 -0500
Hi Jaromir and Dr. Fink,
I don't know if you've been following this discussion but top now has
(or will when the patch-set is pushed) the ability to display NUMA Node
summary and detail views.
Craig thinks the feature is useless for almost everybody even though
most/all processors are now NUMA capable.
I believe Fedora and openSUSE provide libnuma as core packages. And I
think openSUSE even distributes libnuma-devel (numa.h).
When this version of top reaches some future release of yours, will
there be some trigger for specifying --enable-numa at build time?
Or do you think that should be the default, with --disable-numa
as an alternative?
Thanks in advance,
Jim
On Thu, 2013-04-11 at 08:44 +1000, Craig Small wrote:
> Remember that this is all about is numa support on by default, not that
> numa support exists or not.
>
> On Wed, Apr 10, 2013 at 01:39:25AM -0500, Jim Warner wrote:
> > What worries me is how many distros may not bother to enable numa support
> > even though they ship libnuma anyway.
> There's a difference between shipping libnuma and where in the
> priorities of different packages libnuma sits. If a specific
> distribution wants to enable it, they can very simply. If a maintainer
> for a specific distribution missed the enable and someone needs it, they
> can raise a bug report within that distribution.
>
> I had a quick look at the reverse dependencies of libnuma1 on a Debian
> system and its a very small list. In fact if you remove libvirt related
> packages its even smaller. This means most Debian systems would not
> have it installed. I assume its the same for most other distributions
> too.
>
> > My instincts tell me this is a very important procps enhancement.
> > Currently there is no easy way to quickly assess cpu usage in those
> > environments where numa is likely to be used (massively parallel machines).
> Which for the vast majority of users means its completely useless. I've
> run Linux systems since the early 90s, sometimes data centres of them,
> and never come across such devices. I know they exist, but for most
> people they don't run them.
>
> That certainly does not mean the change should not be included and is
> probably essential for a certain group of people. That's why the changes
> should be in but turned off by default.
>
> The option on by default means a build system that compiles 3.3.7 will
> not compile 3.3.8; sure they have to add a new dependency but for what
> gain? It fails path of least surprise test.
>
> > Looks like you'll have to make the final call.
> Remember this is the default behaviour and in my opinion it should be
> off by default. A --enable-numa at configure time enables the numa
> feature.
>
> - Craig
Other related posts:
