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Subject: Re: [hwloc-devel] restricted topology (& topology changes)
From: Samuel Thibault (samuel.thibault_at_[hidden])
Date: 2009-09-27 08:37:34

Brice Goglin, le Sun 27 Sep 2009 14:18:54 +0200, a écrit :
> Samuel Thibault wrote:
> >> but shouldn't it return the restricted topology (or have a method that
> >> returns the restricted topology).
> >>
> >
> > It should already be the default. To get the whole system, see lstopo
> > --help: --whole-system
> Maybe he's referring to when the process launcher does a
> sched_setaffinity/numatcl to restrict this process, as opposed to
> administrator-wide restriction with linux cpusets or so. We could add
> another topology flag for such restrictions.

Ah, right.

> > I've wondered how to implement topology changes indeed. AIX does have a
> > SIGRECONFIG signal for this, I don't know any support from other OSes.
> Maybe there's a inotify way to get such changes in Linux.

There is usually no inotify support for virtual files. I've just tested
that it doesn't work for /sys/bus/usb/devices for instance. We'll have
to ask kernel developers for it.