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 <[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 -- 1.7.2.3 -- 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
