From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Hecht Subject: Re: Stolen and degraded time and schedulers Date: Wed, 14 Mar 2007 13:26:10 -0700 Message-ID: <45F85A62.8050001@vmware.com> References: <45F6D1D0.6080905@goop.org> <1173816769.22180.14.camel@localhost> <45F70A71.9090205@goop.org> <1173821224.1416.24.camel@dwalker1> <45F71EA5.2090203@goop.org> <45F74515.7010808@vmware.com> <45F77C27.8090604@goop.org> <45F846AB.6060200@vmware.com> <45F84E39.7030507@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45F84E39.7030507@goop.org> Sender: linux-kernel-owner@vger.kernel.org To: Jeremy Fitzhardinge Cc: dwalker@mvista.com, cpufreq@lists.linux.org.uk, Linux Kernel Mailing List , Con Kolivas , Chris Wright , Virtualization Mailing List , john stultz , Ingo Molnar , Thomas Gleixner , paulus@au.ibm.com, schwidefsky@de.ibm.com, Rik van Riel List-Id: virtualization@lists.linuxfoundation.org >>> How is cpustat->steal used? How does it get out to usermode? >>> >> Via /proc/stat, used by modern 'top', maybe other utilities. It is >> useful to users who want to see where the time is really going from >> inside a guest when running on a (para)virtual machine. >> >> I believe previous set of xen paravirt-ops patches already handled >> cases #2 and #3 (but no longer do since switching to clockevents), and >> the old vmitime code did also. Obviously, we need revamp this stuff >> to make it fit in with the new clockevents/hrtimer way of doing things. > > I added stolen time accounting to xen-pv_ops last night. For Xen, at > least, it wasn't hard to fit into the clockevent infrastructure. I just > update the stolen time accounting for each cpu when it gets a timer > tick; they seem to get a tick every couple of seconds even when idle. > Sounds good. I don't see this in your patchset you sent yesterday though; did you add it after sending out those patches? if so, could you forward the new patch? does it explicitly prevent stolen time from getting accounted as user/system time or does it just rely on NO_HZ mode sort of happening to work that way (since the one shot timer is skipped ahead for missed ticks)? thanks, Dan