From mboxrd@z Thu Jan 1 00:00:00 1970 From: NISHIGUCHI Naoki Subject: Re: [RFC] Add static priority into credit scheduler Date: Fri, 27 Mar 2009 19:13:59 +0900 Message-ID: <49CCA6E7.2070200@jp.fujitsu.com> References: <49CC3C6A.6050308@jp.fujitsu.com> <49CC7A30.4070202@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Su, Disheng" Cc: George Dunlap , Xen-devel List-Id: xen-devel@lists.xenproject.org Su, Disheng wrote: > NISHIGUCHI Naoki wrote: >> I understand what you mean. >> I doubt whether the rest of cpu not used by RT guest is reflected to >> credit of non-RT guests. If RT guest might monopolize the whole cpu, I >> think the rest of cpu is nothing, therefore non-RT guests have no >> credit. >> > > Yes, it's an issue need to be addressed for client virtualization case, due to the primary guest(e,g Windows) is not a trusted guest. > When detecting one RT guest is monopolize cpu for a while(e.g. 1-2minute), one can: > 1. kill the RT guest... > 2. lower its priority for a while, give other guests the opportunity to run, then restore its previous priority > Any ideas? What I mean is credit_total given to non-RT guest in scheduler. If a PC has 4 core cpu and an RT guest has 4 vcpu, I think credit_total would be 0, because we could not predict behavior of the RT guest . > Oh, forgot to mention you need to pin the RT guest, or try the attached patch. > If you set one guest as high priority, it increases the chance that its vcpus are migrated back and forth, because the priority is fixed and higher than > OVER. I tried your patch. The result was the same. I also pin the RT guest and dom0 as follows, but HVM did not work well. vcpu cpu dom0 0 0 1 1 2 2 3 3 HVM 0 0 1 1 2 2 3 3 It seems to me that idle cpus are not effectively used. > Don't migrate the RT guest in practice. It's the same with Bcredit from my previous experience, isn't it? I think that scheduler should not migrate the vcpu needlessly, but necessary migration should be done. Best regards, Naoki Nishiguchi