From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: performance of credit2 on hybrid workload Date: Wed, 25 May 2011 17:18:29 +0100 Message-ID: <1306340309.21026.8524.camel@elijah> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" 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: David Xu Cc: George Dunlap , xen-devel List-Id: xen-devel@lists.xenproject.org On Mon, 2011-05-23 at 09:15 +0100, David Xu wrote: > Hi, > > > Xen4.1 datasheet tells that credit2 scheduler is designed for latency > sensitive workloads. Does it have some improvement on the hybrid > workload including both the cpu-bound and latency-sensitive i/o work? > For example, if a VM runs a cpu-bound task burning the cpu and a > i/o-bound (latency-sensitive) task simultaneously, will the latency be > guaranteed? And how? At the moment, the "mixed workload" problem, where a single VM does both cpu-intensive and latency-sensitive* workloads, has not been addressed yet. I have some ideas, but I haven't implemented them yet. * i/o-bound is not the same as latency sensitive. They obviously go together frequently, but I would make a distinction between them. For example, an scp (copy over ssh) can easily become cpu-bound if there is competition for the cpu -- but it is nonetheless latency sensitive. (I guess to put it another way, a workload which is latency-sensitive may become i/o-bound if its scheduling latency is too high.) -George