On Tue, 2009-08-04 at 17:07 +0200, Martin Schwidefsky wrote: > On Tue, 04 Aug 2009 16:16:38 +0200 > Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > > These patches never seem to have made it onto LKML?! > > > > On Mon, 2007-08-20 at 15:13 +0200, Laurent Vivier wrote: > > > The aim of these four patches is to introduce Virtual Machine time accounting. > > > > > > _Ingo_, as these patches modify files of the scheduler, could you have a look to > > > them, please ? > > > > > > [PATCH 1/4] as recent CPUs introduce a third running state, after "user" and > > > "system", we need a new field, "guest", in cpustat to store the time used by > > > the CPU to run virtual CPU. Modify /proc/stat to display this new field. > > > > > > [PATCH 2/4] like for cpustat, introduce the "gtime" (guest time of the task) and > > > "cgtime" (guest time of the task children) fields for the > > > tasks. Modify signal_struct and task_struct. Modify /proc/<pid>/stat to display > > > these new fields. > > > > > > [PATCH 3/4] modify account_system_time() to add cputime to cpustat->guest if we > > > are running a VCPU. We add this cputime to cpustat->user instead of > > > cpustat->system because this part of KVM code is in fact user code although it > > > is executed in the kernel. We duplicate VCPU time between guest and user to > > > allow an unmodified "top(1)" to display correct value. A modified "top(1)" is > > > able to display good cpu user time and cpu guest time by subtracting cpu guest > > > time from cpu user time. Update "gtime" and "cgtime" in signal_struct and > > > task_struct accordingly. > > > > > > [PATCH 4/4] Modify KVM to update guest time accounting. > > > > Isn't this exactly what CONFIG_VIRT_CPU_ACCOUNTING is about? > > Not really, CONFIG_VIRT_CPU_ACCOUNT is a mechanism to sort out the > steal time in the >guest< and to increase the precision of the cpu > accounting values in general. The patches from Laurent improve the > code in the >host< that sorts out guest time vs. system time. Ah, that wasn't clear, it keeps mentioning guest all over the place ;-) So its going to split user time into user and guest. Does that really make sense? For the host kernel it really is just another user process, no? > The patches do make sense to me. No idea there as they never made it to my lkml folder. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
