Messages in this thread | | | Subject | Re: [PATCH] virtual sched_clock() for s390 | From | Jan Glauber <> | Date | Thu, 19 Jul 2007 21:07:03 +0000 |
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On Thu, 2007-07-19 at 21:38 +0200, Ingo Molnar wrote: > * Jan Glauber <jang@linux.vnet.ibm.com> wrote: > > > > still, CFS needs time measurement across idle periods as well, for > > > another purpose: to be able to do precise task statistics for /proc. > > > (for top, ps, etc.) So it's still true that sched_clock() should > > > include idle periods too. > > > > I'm not sure, s390 already has an implemetation for precise accounting > > in the architecture code, does CFS also improve accounting data? > > what kind of precise accounting does s390 have in the architecture code? > CFS changes task (and load) accounting to be sched_clock() driven in > essence.
s390 has per-process accounting that is aware of virtual cpu time, implemented in arch/s390/kernel/time.c: account_ticks() and arch/s390/kernel/vtime.c: account_*_vtime(). Timestamps are taken in entry.S for system calls, interrupts and other system entries and are accounted later, we don't call update_process_times().
Jan
> Ingo > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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