diff options
| author | Rik van Riel <riel@redhat.com> | 2016-07-13 16:50:02 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-07-14 10:42:34 +0200 |
| commit | b58c35840521bb02b150e1d0d34ca9197f8b7145 (patch) | |
| tree | a1641840e235a1035e7ad8c4276a77d25552ba4e /kernel | |
| parent | 57430218317e5b280a80582a139b26029c25de6c (diff) | |
sched/cputime: Replace VTIME_GEN irq time code with IRQ_TIME_ACCOUNTING code
The CONFIG_VIRT_CPU_ACCOUNTING_GEN irq time tracking code does not
appear to currently work right.
On CPUs without nohz_full=, only tick based irq time sampling is
done, which breaks down when dealing with a nohz_idle CPU.
On firewalls and similar systems, no ticks may happen on a CPU for a
while, and the irq time spent may never get accounted properly. This
can cause issues with capacity planning and power saving, which use
the CPU statistics as inputs in decision making.
Remove the VTIME_GEN vtime irq time code, and replace it with the
IRQ_TIME_ACCOUNTING code, when selected as a config option by the user.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1468421405-20056-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/cputime.c | 16 |
1 files changed, 3 insertions, 13 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index db82ae12cf01..ca7e33cb0967 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -711,14 +711,14 @@ static cputime_t vtime_delta(struct task_struct *tsk) static cputime_t get_vtime_delta(struct task_struct *tsk) { unsigned long now = READ_ONCE(jiffies); - cputime_t delta, steal; + cputime_t delta, other; delta = jiffies_to_cputime(now - tsk->vtime_snap); - steal = steal_account_process_time(delta); + other = account_other_time(delta); WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE); tsk->vtime_snap = now; - return delta - steal; + return delta - other; } static void __vtime_account_system(struct task_struct *tsk) @@ -738,16 +738,6 @@ void vtime_account_system(struct task_struct *tsk) write_seqcount_end(&tsk->vtime_seqcount); } -void vtime_gen_account_irq_exit(struct task_struct *tsk) -{ - write_seqcount_begin(&tsk->vtime_seqcount); - if (vtime_delta(tsk)) - __vtime_account_system(tsk); - if (context_tracking_in_user()) - tsk->vtime_snap_whence = VTIME_USER; - write_seqcount_end(&tsk->vtime_seqcount); -} - void vtime_account_user(struct task_struct *tsk) { cputime_t delta_cpu; |