Messages in this thread |  | | Date | Tue, 7 Jan 2020 10:13:15 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/3] sched/cputime: code cleanup in irqtime_account_process_tick |
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On Mon, Jan 06, 2020 at 04:53:51PM +0100, Frederic Weisbecker wrote: > On Thu, Jan 02, 2020 at 06:07:53PM +0800, Alex Shi wrote: > > In this func, since account_system_time() considers guest time account > > and other system time. we could fold the account_guest_time into > > account_system_time() to simply the code. > > > > Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> > > Cc: Ingo Molnar <mingo@redhat.com> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Frederic Weisbecker <fweisbec@gmail.com> > > Cc: Wanpeng Li <wanpeng.li@hotmail.com> > > Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> > > Cc: Thomas Gleixner <tglx@linutronix.de> > > Cc: linux-kernel@vger.kernel.org > > --- > > kernel/sched/cputime.c | 9 +++------ > > 1 file changed, 3 insertions(+), 6 deletions(-) > > > > diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c > > index cff3e656566d..46b837e94fce 100644 > > --- a/kernel/sched/cputime.c > > +++ b/kernel/sched/cputime.c > > @@ -381,13 +381,10 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick, > > account_system_index_time(p, cputime, CPUTIME_SOFTIRQ); > > } else if (user_tick) { > > account_user_time(p, cputime); > > - } else if (p == this_rq()->idle) { > > + } else if ((p != this_rq()->idle) || (irq_count() != HARDIRQ_OFFSET)) > > + account_system_time(p, HARDIRQ_OFFSET, cputime); > > + else > > I fear we can't really play the exact same game as account_process_tick() here. > Since this is irqtime precise accounting, we have already computed the > irqtime delta in account_other_time() (or we will at some point in the future) > and substracted it from the ticks to account. This means that the remaining cputime > to account has to be either utime/stime/gtime/idle-time but not interrupt time, or > we may account interrupt time twice. And account_system_time() tries to account > irq time, for example if we interrupt a softirq.
OK, I've dropped 2 and 3. Thanks Frederic!
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