From: Glauber Costa <glommer@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: kvm@vger.kernel.org, avi@redhat.com, zamsden@redhat.com,
mtosatti@redhat.com, riel@redhat.com, mingo@elte.hu,
jeremy@goop.org
Subject: Re: [RFC 5/8] change kernel accounting to include steal time
Date: Mon, 30 Aug 2010 14:26:14 -0300 [thread overview]
Message-ID: <20100830172614.GM17084@mothafucka.localdomain> (raw)
In-Reply-To: <1283186785.1820.1174.camel@laptop>
On Mon, Aug 30, 2010 at 06:46:25PM +0200, Peter Zijlstra wrote:
> On Mon, 2010-08-30 at 12:06 -0400, Glauber Costa wrote:
> > This patch proposes a common steal time implementation. When no
> > steal time is accounted, we just add a branch to the current
> > accounting code, that shouldn't add much overhead.
>
> But why not use alternative code and avoid that conditional
> all-together?
>
> > * Account user cpu time to a process.
> > * @p: the process that the cpu time gets accounted to
> > @@ -3169,6 +3179,12 @@ void account_user_time(struct task_struct *p, cputime_t cputime,
> > struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
> > cputime64_t tmp;
> >
> > + tmp = get_steal_time_from_hypervisor();
> > + if (tmp) {
> > + account_steal_time(tmp);
> > + return;
> > + }
> > +
> > /* Add user time to process. */
> > p->utime = cputime_add(p->utime, cputime);
> > p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
> > @@ -3234,6 +3250,12 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
> > return;
> > }
> >
> > + tmp = get_steal_time_from_hypervisor();
> > + if (tmp) {
> > + account_steal_time(tmp);
> > + return;
> > + }
> > +
> > /* Add system time to process. */
> > p->stime = cputime_add(p->stime, cputime);
> > p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
>
> Why replicate that code and not restructure account_process_tick()?
For both: because this way is easier, and this is just an rfc, so I
am mainly interested in getting convergence on the design, or leaving
this behind altogether. I do agree with both your comments, btw
next prev parent reply other threads:[~2010-08-30 17:26 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-30 16:06 [RFC v2 0/7] kvm stael time implementation Glauber Costa
2010-08-30 16:06 ` [RFC v2 1/7] change headers preparing for steal time Glauber Costa
2010-08-30 16:06 ` [RFC 1/8] Implement getnsboottime kernel API Glauber Costa
2010-08-30 16:06 ` [RFC v2 2/7] always call kvm_write_guest Glauber Costa
2010-08-30 16:06 ` [RFC 2/8] change headers preparing for steal time Glauber Costa
2010-08-30 16:06 ` [RFC 3/8] always call kvm_write_guest Glauber Costa
2010-08-30 16:06 ` [RFC v2 3/7] measure time out of guest Glauber Costa
2010-08-30 16:06 ` [RFC v2 4/7] change kernel accounting to include steal time Glauber Costa
2010-08-30 16:06 ` [RFC 4/8] measure time out of guest Glauber Costa
2010-08-30 16:06 ` [RFC 5/8] change kernel accounting to include steal time Glauber Costa
2010-08-30 16:06 ` [RFC v2 5/7] kvm steal time implementation Glauber Costa
2010-08-30 16:06 ` [RFC 6/8] " Glauber Costa
2010-08-30 16:06 ` [RFC v2 6/7] touch softlockup watchdog Glauber Costa
2010-08-30 16:06 ` [RFC v2 7/7] tell guest about steal time feature Glauber Costa
2010-08-30 16:06 ` [RFC 7/8] touch softlockup watchdog Glauber Costa
2010-08-30 16:06 ` [RFC 8/8] tell guest about steal time feature Glauber Costa
2010-08-30 17:33 ` [RFC v2 6/7] touch softlockup watchdog Jeremy Fitzhardinge
2010-08-30 18:07 ` Glauber Costa
2010-08-30 16:46 ` [RFC 5/8] change kernel accounting to include steal time Peter Zijlstra
2010-08-30 17:26 ` Glauber Costa [this message]
2010-08-30 17:30 ` [RFC v2 4/7] " Jeremy Fitzhardinge
2010-08-30 18:39 ` Rik van Riel
2010-08-30 19:07 ` Jeremy Fitzhardinge
2010-08-30 19:14 ` Peter Zijlstra
2010-08-30 19:17 ` Rik van Riel
2010-08-30 19:20 ` Peter Zijlstra
2010-08-30 19:45 ` Rik van Riel
2010-08-30 22:56 ` Jeremy Fitzhardinge
2010-08-30 23:03 ` Rik van Riel
2010-08-31 8:11 ` Peter Zijlstra
2010-09-02 18:19 ` Glauber Costa
2010-09-03 3:24 ` Jeremy Fitzhardinge
2010-09-03 7:18 ` Peter Zijlstra
2010-09-01 23:56 ` [RFC 1/8] Implement getnsboottime kernel API Zachary Amsden
2010-08-30 16:37 ` [RFC v2 0/7] kvm stael time implementation Peter Zijlstra
2010-08-30 16:45 ` Jeremy Fitzhardinge
2010-08-30 17:21 ` Glauber Costa
2010-08-30 17:20 ` Jeremy Fitzhardinge
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