Re: [PATCH v3 3/6] KVM-GST: KVM Steal time accounting

From: Avi Kivity
Date: Tue Feb 15 2011 - 10:17:30 EST


On 02/15/2011 04:45 PM, Peter Zijlstra wrote:
On Tue, 2011-02-15 at 16:35 +0200, Avi Kivity wrote:
On 02/11/2011 08:19 PM, Glauber Costa wrote:
This patch accounts steal time time in kernel/sched.
I kept it from last proposal, because I still see advantages
in it: Doing it here will give us easier access from scheduler
variables such as the cpu rq. The next patch shows an example of
usage for it.

Since functions like account_idle_time() can be called from
multiple places, not only account_process_tick(), steal time
grabbing is repeated in each account function separatedely.

I still don't see how we export this to userspace for top(1) and friends.

The existing steal time stuff is:

kernel/sched.c:account_steal_time()

cpustat->steal = cputime64_add(cpustat->steal, cputime64);

and

fs/proc/stat.c:show_stat()


steal = cputime64_add(steal, kstat_cpu(i).cpustat.steal);

seq_printf(p, "cpu %llu %llu %llu %llu %llu %llu %llu %llu %llu "
"%llu\n",
(unsigned long long)cputime64_to_clock_t(user),
(unsigned long long)cputime64_to_clock_t(nice),
(unsigned long long)cputime64_to_clock_t(system),
(unsigned long long)cputime64_to_clock_t(idle),
(unsigned long long)cputime64_to_clock_t(iowait),
(unsigned long long)cputime64_to_clock_t(irq),
(unsigned long long)cputime64_to_clock_t(softirq),
(unsigned long long)cputime64_to_clock_t(steal),
(unsigned long long)cputime64_to_clock_t(guest),
(unsigned long long)cputime64_to_clock_t(guest_nice));



Ah, so we're all set. Do you know if any user tools process this information?
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