From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH RFC 0/3] Add guest cpu_entitlement reporting Date: Mon, 27 Aug 2012 11:55:20 -0700 Message-ID: <503BC298.3080306@redhat.com> References: <20120823231346.11681.1502.stgit@lambeau> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, peterz@infradead.org, mtosatti@redhat.com, glommer@parallels.com, mingo@redhat.com To: Michael Wolf Return-path: In-Reply-To: <20120823231346.11681.1502.stgit@lambeau> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 08/23/2012 04:14 PM, Michael Wolf wrote: > This is an RFC regarding the reporting of stealtime. In the case of > where you have a system that is running with partial processors such as > KVM the user may see steal time being reported in accounting tools such > as top or vmstat. This can cause confusion for the end user. To > ease the confusion this patch set adds a sysctl interface to set the > cpu entitlement. This is the percentage of cpu that the guest system is > expected to receive. As long as the steal time is within its expected > range it will show up as 0 in /proc/stat. The user will then see in the > accounting tools that they are getting a full utilization of the cpu > resources assigned to them. > > This patchset is changing the contents/output of /proc/stat and could affect > user tools. However the default setting is that the cpu is entitled to 100% > so the code will act as before. Also another field could be added to the > /proc/stat output and show the unaltered steal time. Since this additional > field could cause more confusion than it would clear up I have left it out > for now. > How would a guest know what its entitlement is? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.