Re: [PATCH 00/07][RFC] i386: NUMA emulation

Magnus Damm
2005-10-03T10:02:08Z

On 10/3/05, David Lang <david.lang@digitalinsight.com> wrote:
> On Mon, 3 Oct 2005, Magnus Damm wrote:
>
> > On 10/1/05, Dave Hansen <haveblue@us.ibm.com> wrote:
> >> On Fri, 2005-09-30 at 16:33 +0900, Magnus Damm wrote:
> >>> These patches implement NUMA memory node emulation for regular i386 PC:s.
> >>>
> >>> NUMA emulation could be used to provide coarse-grained memory resource control
> >>> using CPUSETS. Another use is as a test environment for NUMA memory code or
> >>> CPUSETS using an i386 emulator such as QEMU.
> >>
> >> This patch set basically allows the "NUMA depends on SMP" dependency to
> >> be removed. I'm not sure this is the right approach. There will likely
> >> never be a real-world NUMA system without SMP. So, this set would seem
> >> to include some increased (#ifdef) complexity for supporting SMP && !
> >> NUMA, which will likely never happen in the real world.
> >
> > Yes, this patch set removes "NUMA depends on SMP". It also adds some
> > simple NUMA emulation code too, but I am sure you are aware of that!
> > =)
> >
> > I agree that it is very unlikely to find a single-processor NUMA
> > system in the real world. So yes, "[PATCH 02/07] i386: numa on
> > non-smp" adds _some_ extra complexity. But because SMP is set when
> > supporting more than one cpu, and NUMA is set when supporting more
> > than one memory node, I see no reason why they should be dependent on
> > each other. Except that they depend on each other today and breaking
> > them loose will increase complexity a bit.
>
> hmm, observation from the peanut gallery, would it make sene to look at
> useing the NUMA code on single proc machines that use PAE to access more
> then 4G or ram on a 32 bit system?

Hm, maybe? =) What would you like to accomplish by that?

/ magnus