-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Avi Kivity Sent: Sunday, November 30, 2008 4:50 PM To: Andi Kleen Cc: Andre Przywara; [email protected] Subject: Re: [PATCH 0/3] KVM-userspace: add NUMA support for guests
> Well, testing is the only way to know. I'm particularly interested in > how Windows will perform, since we know so little about its internals. > > From some light googling, it looks like Windows has a home node for a > thread, and will allocate pages from the home node even when the thread > is executing on some other node temporarily. It also does automatic > page migration in some cases. Well, there's a couple of way this works: - A program can explicitly specify which NUMA node to use for NUMA-aware apps using the new NUMA-enabled APIs. - Otherwise, a default NUMA node is chosen. For older systems (believe prior to Vista), the default NUMA node is the processor upon which the thread was running. For modern systems, the ideal processor for the thread is used. (The ideal processor is which proc the scheduler will try and run the thread on. It is not a hard association as with an affinity mask, in that the scheduler will run the thread on a different processor if it has to, but it will prefer the ideal processor.) I think later versions of SQL Server are probably a good bet if you want to test something on Windows that is fully NUMA-aware. Most smaller stuff is of course using the default policies. - S -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
