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. The patches do make sense to me. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
