On Mon, 2011-07-04 at 11:32 -0400, Glauber Costa wrote: > This patch accounts steal time time in account_process_tick. > If one or more tick is considered stolen in the current > accounting cycle, user/system accounting is skipped. Idle is fine, > since the hypervisor does not report steal time if the guest > is halted. > > Accounting steal time from the core scheduler give us the > advantage of direct acess to the runqueue data. In a later > opportunity, it can be used to tweak cpu power and make > the scheduler aware of the time it lost. > > Signed-off-by: Glauber Costa <glommer@xxxxxxxxxx> > CC: Rik van Riel <riel@xxxxxxxxxx> > CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Venki, can you have a look at that irqtime_account_process_tick(), I think adding the steal time up front like this is fine, because it suffers from the same 'problem' as both irqtime thingies. > CC: Avi Kivity <avi@xxxxxxxxxx> > CC: Anthony Liguori <aliguori@xxxxxxxxxx> > CC: Eric B Munson <emunson@xxxxxxxxx> > --- > kernel/sched.c | 41 +++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 41 insertions(+), 0 deletions(-) > > diff --git a/kernel/sched.c b/kernel/sched.c > index 3f2e502..aa6c030 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -75,6 +75,7 @@ > #include <asm/tlb.h> > #include <asm/irq_regs.h> > #include <asm/mutex.h> > +#include <asm/paravirt.h> > > #include "sched_cpupri.h" > #include "workqueue_sched.h" > @@ -528,6 +529,9 @@ struct rq { > #ifdef CONFIG_IRQ_TIME_ACCOUNTING > u64 prev_irq_time; > #endif > +#ifdef CONFIG_PARAVIRT > + u64 prev_steal_time; > +#endif > > /* calc_load related fields */ > unsigned long calc_load_update; > @@ -1953,6 +1957,18 @@ void account_system_vtime(struct task_struct *curr) > } > EXPORT_SYMBOL_GPL(account_system_vtime); > > +#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ > + > +#ifdef CONFIG_PARAVIRT > +static inline u64 steal_ticks(u64 steal) > +{ > + if (unlikely(steal > NSEC_PER_SEC)) > + return div_u64(steal, TICK_NSEC); > + > + return __iter_div_u64_rem(steal, TICK_NSEC, &steal); > +} > +#endif > + > static void update_rq_clock_task(struct rq *rq, s64 delta) > { > s64 irq_delta; > @@ -3845,6 +3861,25 @@ void account_idle_time(cputime_t cputime) > cpustat->idle = cputime64_add(cpustat->idle, cputime64); > } > > +static __always_inline bool steal_account_process_tick(void) > +{ > +#ifdef CONFIG_PARAVIRT > + if (static_branch(¶virt_steal_enabled)) { > + u64 steal, st = 0; > + > + steal = paravirt_steal_clock(smp_processor_id()); > + steal -= this_rq()->prev_steal_time; > + > + st = steal_ticks(steal); > + this_rq()->prev_steal_time += st * TICK_NSEC; > + > + account_steal_time(st); > + return st; > + } > +#endif > + return false; > +} > + > #ifndef CONFIG_VIRT_CPU_ACCOUNTING > > #ifdef CONFIG_IRQ_TIME_ACCOUNTING > @@ -3876,6 +3911,9 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick, > cputime64_t tmp = cputime_to_cputime64(cputime_one_jiffy); > struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; > > + if (steal_account_process_tick()) > + return; > + > if (irqtime_account_hi_update()) { > cpustat->irq = cputime64_add(cpustat->irq, tmp); > } else if (irqtime_account_si_update()) { > @@ -3929,6 +3967,9 @@ void account_process_tick(struct task_struct *p, int user_tick) > return; > } > > + if (steal_account_process_tick()) > + return; > + > if (user_tick) > account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); > else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html