David Xu wrote this message on Mon, Oct 09, 2006 at 06:34 +0800: > On Monday 09 October 2006 04:58, Ivan Voras wrote: > > Kip Macy wrote: > > > It will only cover the single chip Niagara 2 boxes. > > > > Oh right, they'll doing multi chips in Niagara 2 :) Go Sun :) > > > > Still, single T2 chips should be more common, so I'd guess it will pay > > to optimize for that case. > > > > (For the rest of the audience: Niagara 1 has 32 logical CPUs and > > supports only one physical CPU/socket; Niagara 2 will have 64 logical > > CPUs and support > 1 CPUs/sockets; so a 2 socket Niagara 2 box will have > > 128 logical processors! Cue SciFi music...) > > > > Any word on how will they handle migration of threads across sockets (or > > will it be OS's job)? Judging from T1 architecture, I think such event > > would create a very large performance penalty, but I'm not an expert. > > __________ > > The current 4BSD scheduler does not handle large number of cores very well, > also the single sched_lock will be a bottleneck for such a configuration. Bad enough that Kip had to reduce HZ down to 100... since sched_lock ends up serializing ALL cpus when scheduling needs to happen.. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."Received on Sun Oct 08 2006 - 20:51:59 UTC
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