Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757940Ab1BKSVm (ORCPT ); Fri, 11 Feb 2011 13:21:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:61190 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932254Ab1BKSVY (ORCPT ); Fri, 11 Feb 2011 13:21:24 -0500 From: Glauber Costa To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Rik van Riel , Jeremy Fitzhardinge , Peter Zijlstra , Avi Kivity Subject: [PATCH v3 3/6] KVM-GST: KVM Steal time accounting Date: Fri, 11 Feb 2011 13:19:21 -0500 Message-Id: <1297448364-14051-4-git-send-email-glommer@redhat.com> In-Reply-To: <1297448364-14051-1-git-send-email-glommer@redhat.com> References: <1297448364-14051-1-git-send-email-glommer@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4138 Lines: 133 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. 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 | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+), 0 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index d747f94..5dbf509 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)(int cpu); 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 18d38e4..60b0cf8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -524,6 +524,8 @@ struct rq { u64 prev_irq_time; #endif + u64 prev_steal_ticks; + /* calc_load related fields */ unsigned long calc_load_update; long calc_load_active; @@ -1780,6 +1782,16 @@ static void deactivate_task(struct rq *rq, struct task_struct *p, int flags) dec_nr_running(rq); } +u64 (*hypervisor_steal_time)(int cpu) = NULL; + +static u64 steal_time_clock(int cpu) +{ + if (!hypervisor_steal_time) + return 0; + + return hypervisor_steal_time(cpu); +} + #ifdef CONFIG_IRQ_TIME_ACCOUNTING /* @@ -3509,6 +3521,33 @@ unsigned long long thread_group_sched_runtime(struct task_struct *p) } /* + * 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; + + steal = steal_time_clock(smp_processor_id()); + + st = steal / TICK_NSEC - this_rq()->prev_steal_ticks; + + this_rq()->prev_steal_ticks += st; + + if (!st || is_idle) + return 0; + + account_steal_time(st); + return 1; +} + +/* * Account user cpu time to a process. * @p: the process that the cpu time gets accounted to * @cputime: the cpu time spent in user space since the last update @@ -3520,6 +3559,9 @@ 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 +3622,9 @@ 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 +3672,8 @@ 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 -- 1.7.2.3 -- 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/