Messages in this thread Patch in this message | | | From | Thomas Gleixner <> | Subject | Re: [PATCH 4/5] irqtime: Move irqtime entry accounting after irq offset incrementation | Date | Tue, 01 Dec 2020 14:34:49 +0100 |
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On Tue, Dec 01 2020 at 12:40, Frederic Weisbecker wrote: > On Tue, Dec 01, 2020 at 12:33:26PM +0100, Thomas Gleixner wrote: >> > /* >> > * We do not account for softirq time from ksoftirqd here. >> > * We want to continue accounting softirq time to ksoftirqd thread >> > * in that case, so as not to confuse scheduler with a special task >> > * that do not consume any time, but still wants to run. >> > */ >> > if (pc & HARDIRQ_MASK) >> > irqtime_account_delta(irqtime, delta, CPUTIME_IRQ); >> > else if ((pc & SOFTIRQ_OFFSET) && curr != this_cpu_ksoftirqd()) >> > irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ); >> > } >> >> Why not making all of this explicit instead of these conditionals? > > Hmm, I'm not sure I get what you suggest?
Instead of playing games with preeempt count and offsets and checking for ksoftirqd, can't you just have:
account_hardirqtime() account_softirqtime()
and call them from the right spots. See the below for illustration (it's obviously incomplete).
Thanks,
tglx --- --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -377,6 +377,7 @@ static inline void invoke_softirq(void) return; if (!force_irqthreads) { + account_softirq_enter_time(current); #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK /* * We can safely execute softirq on the current stack if @@ -391,6 +392,7 @@ static inline void invoke_softirq(void) * to prevent from any overrun. */ do_softirq_own_stack(); + account_softirq_exit_time(current); #endif } else { wakeup_softirqd(); @@ -417,7 +419,7 @@ static inline void __irq_exit_rcu(void) #else lockdep_assert_irqs_disabled(); #endif - account_irq_exit_time(current); + account_hardirq_exit_time(current); preempt_count_sub(HARDIRQ_OFFSET); if (!in_interrupt() && local_softirq_pending()) invoke_softirq();
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