|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] Xen sched: Fix multiple runqueues in credit2
On 06.02.2014 14:44, Dario Faggioli wrote: On gio, 2014-02-06 at 10:13 +0100, Juergen Gross wrote:On 06.02.2014 09:58, Justin Weaver wrote:This patch attempts to address the issue of the Xen Credit 2 Scheduler only creating one vCPU run queue on multiple physical processor systems. It should be creating one run queue per physical processor. CPU 0 does not get a starting callback, so it is hard coded to run queue 0. At the time this happens, socket information is not available for CPU 0. Socket information is available for each individual CPU when each gets the STARTING callback (I believe socket information is also available for CPU 0 by that time). This patch adds the following algorithm... IF cpu is on the same socket as CPU 0, add it to run queue 0You should check whether cpu and CPU0 are in the same cpupool. BTW: CPU0 is allowed to be moved to another cpupool, too.Good points. However, the code, as it is now, does not look to care much about cpupools while constructing this 'one runqueue per socket' thing, does it? I mean, what happens, right now, if, either after or credit2 builds up the runqueues --say one per socket-- two pCPUs from the same socket are in different cpupools? It looks to me that things are considered orthogonal while, as you say, tthy may not be... I guess I'll try that ASAP and let you know... My point being that, Justing is trying to fix a bug in credit2, which says it constructs one runqueue per socket, while it ends up with only one runqueue at all. If there is another bug, or buggy behavior, wrt how this interacts with cpupools, although we should fix that too, that's pre-existent and needs addressing in a dedicated patch (series), isn't it? Now it will construct one runqueue per cpupool. There is one sched_private structure per cpupool! I'm not sure what will happen with the change proposed by Justin in case of multiple credit2 cpupools... Juergen -- Juergen Gross Principal Developer Operating Systems PBG PDG ES&S SWE OS6 Telephone: +49 (0) 89 62060 2932 Fujitsu e-mail: juergen.gross@xxxxxxxxxxxxxx Mies-van-der-Rohe-Str. 8 Internet: ts.fujitsu.com D-80807 Muenchen Company details: ts.fujitsu.com/imprint.html _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |