> Something _really_ weird happened to your quoting; you quoted my > email, but your email client said you wrote it. > > On Mon, Dec 17, 2012 at 2:00 AM, J. Roeleveld <jo...@antarean.org> wrote: >>> On Sun, Dec 16, 2012 at 10:39 AM, J. Roeleveld <jo...@antarean.org> >>> wrote: > > ^-- weird --^
Very weird, especially as I am using the same client now (squirrelmail) and I don't see that line at all now. >>>> On Sunday, December 16, 2012 01:52:46 PM Volker Armin Hemmann wrote: >>>>> Am Samstag, 15. Dezember 2012, 20:57:24 schrieb J. Roeleveld: >>>>> > Even on a system with only 2 sockets, it can be useful to have NUMA >>>>> > available. >>>>> >>>>> or not, because it costs you performance. >>>> >>>> When does it cost performance? >>>> In all situations? >>> >>> It adds some additional logic to memory allocation (put an allocation >>> near the process that uses it) and to process scheduling (keep the >>> process near its memory, but bump it to a more distant idle core if >>> necessary). >> >> That's the way it's supposed to work, yes :) >> >>> In all honestly, it's not a performance loss you're likely to notice, >>> unless you're so in need of squeezing out every spare cycle that you >>> most definitely _have_ hardware where there are disconnected memory >>> banks. I'm not convinced it's even measurable for us mundanes and our >>> hardware. >> >> I don't think I would notice it either, but as the system I have >> supports >> it, I want to use it. >> And then I want to be certain it actually supports it correctly. >> >> The system I'm talking about is used for testing purposes. Running >> multiple VMs. As far as I know, Xen has support for it, just need to >> configure it properly. >> And for this usecase, I think NUMA with only 2 physical CPUs should make >> a >> positive difference. > > Don't get me wrong; I was arguing that it shouldn't hurt to have it > enabled. :) I know, just wanted to add the use-case for considering NUMA a usefull option even with only 2 physical CPUs :) -- Joost
