On Fri, 2011-01-28 at 17:16 -0800, Jeremy Fitzhardinge wrote: > 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?
Guest. > 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 <[email protected]> > > CC: Rik van Riel <[email protected]> > > CC: Jeremy Fitzhardinge <[email protected]> > > CC: Peter Zijlstra <[email protected]> > > CC: Avi Kivity <[email protected]> > > --- > > 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 > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
