From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754700Ab1A2BQh (ORCPT ); Fri, 28 Jan 2011 20:16:37 -0500 Received: from claw.goop.org ([74.207.240.146]:47499 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752787Ab1A2BQg (ORCPT ); Fri, 28 Jan 2011 20:16:36 -0500 Message-ID: <4D436A68.2000100@goop.org> Date: Fri, 28 Jan 2011 17:16:24 -0800 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.7 MIME-Version: 1.0 To: Glauber Costa CC: "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "aliguori@us.ibm.com" , Rik van Riel , Peter Zijlstra , Avi Kivity Subject: Re: [PATCH v2 3/6] KVM-GST: KVM Steal time accounting References: <1296244340-15173-1-git-send-email-glommer@redhat.com> <1296244340-15173-4-git-send-email-glommer@redhat.com> In-Reply-To: <1296244340-15173-4-git-send-email-glommer@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/28/2011 11:52 AM, 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. Is this used on the host or guest side? J > 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. > > Signed-off-by: Glauber Costa > CC: Rik van Riel > CC: Jeremy Fitzhardinge > CC: Peter Zijlstra > CC: Avi Kivity > --- > include/linux/sched.h | 1 + > kernel/sched.c | 41 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 42 insertions(+), 0 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index d747f94..77e9297 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -302,6 +302,7 @@ long io_schedule_timeout(long timeout); > extern void cpu_init (void); > extern void trap_init(void); > extern void update_process_times(int user); > +extern u64 (*hypervisor_steal_time)(void); > extern void scheduler_tick(void); > > extern void sched_show_task(struct task_struct *p); > diff --git a/kernel/sched.c b/kernel/sched.c > index ea3e5ef..7765e9d 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -3508,6 +3508,39 @@ unsigned long long thread_group_sched_runtime(struct task_struct *p) > return ns; > } > > +u64 (*hypervisor_steal_time)(void) = NULL; > + > +/* > + * We have to at flush steal time information every time something else > + * is accounted. Since the accounting functions are all visible to the rest > + * of the kernel, it gets tricky to do them in one place. This helper function > + * helps us. > + * > + * When the system is idle, the concept of steal time does not apply. We just > + * tell the underlying hypervisor that we grabbed the data, but skip steal time > + * accounting > + */ > +static int touch_steal_time(int is_idle) > +{ > + u64 steal, st; > + > + if (!hypervisor_steal_time) > + return 0; > + > + steal = hypervisor_steal_time(); > + > + st = usecs_to_cputime(steal / 1000); > + > + if (is_idle) > + return 0; > + > + if (st) { > + account_steal_time(st); > + return 1; > + } > + return 0; > +} > + > /* > * Account user cpu time to a process. > * @p: the process that the cpu time gets accounted to > @@ -3520,6 +3553,9 @@ void account_user_time(struct task_struct *p, cputime_t cputime, > struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; > cputime64_t tmp; > > + if (touch_steal_time(0)) > + return; > + > /* Add user time to process. */ > p->utime = cputime_add(p->utime, cputime); > p->utimescaled = cputime_add(p->utimescaled, cputime_scaled); > @@ -3580,6 +3616,9 @@ void account_system_time(struct task_struct *p, int hardirq_offset, > struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; > cputime64_t tmp; > > + if (touch_steal_time(0)) > + return; > + > if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { > account_guest_time(p, cputime, cputime_scaled); > return; > @@ -3627,6 +3666,8 @@ void account_idle_time(cputime_t cputime) > cputime64_t cputime64 = cputime_to_cputime64(cputime); > struct rq *rq = this_rq(); > > + touch_steal_time(1); > + > if (atomic_read(&rq->nr_iowait) > 0) > cpustat->iowait = cputime64_add(cpustat->iowait, cputime64); > else