On Thu, 2016-06-23 at 15:52 +0200, Paolo Bonzini wrote:
>
> On 22/06/2016 23:55, Rik van Riel wrote:
> >
> > >
> > > >
> > > > + hardirq_time =
> > > > READ_ONCE(per_cpu(cpu_hardirq_time,
> > > > cpu));
> > > Which makes this per_cpu(,cpu) usage somewhat curious. What's
> > > wron
On 22/06/2016 23:55, Rik van Riel wrote:
> > > + hardirq_time = READ_ONCE(per_cpu(cpu_hardirq_time,
> > > cpu));
> > Which makes this per_cpu(,cpu) usage somewhat curious. What's wrong
> > with __this_cpu_read() ?
>
> I played around with it a bit, and it seems that
> __this_cpu_read does
From: Rik van Riel
Drop local_irq_save/restore from irqtime_account_irq.
Instead, have softirq and hardirq track their time spent
independently, with the softirq code subtracting hardirq
time that happened during the duration of the softirq run.
The softirq code can be interrupted by hardirq cod
On Tue, 2016-06-21 at 23:49 +0200, Peter Zijlstra wrote:
> On Thu, Jun 16, 2016 at 12:06:07PM -0400, r...@redhat.com wrote:
> >
> > @@ -53,36 +56,72 @@ DEFINE_PER_CPU(seqcount_t, irq_time_seq);
> > * softirq -> hardirq, hardirq -> softirq
> > *
> > * When exiting hardirq or softirq time, acc
On Tue, Jun 21, 2016 at 06:23:34PM -0400, Rik van Riel wrote:
> > > cpu = smp_processor_id();
> > Per this smp_processor_id() usage, preemption is disabled.
>
> This code is called from the timer code. Surely preemption
> is already disabled?
That's what I said.
> > >
> > > + /*
> > > + * So
On Thu, Jun 16, 2016 at 12:06:07PM -0400, r...@redhat.com wrote:
> @@ -53,36 +56,72 @@ DEFINE_PER_CPU(seqcount_t, irq_time_seq);
> * softirq -> hardirq, hardirq -> softirq
> *
> * When exiting hardirq or softirq time, account the elapsed time.
> + *
> + * When exiting softirq time, subtract t
On Wed, 2016-06-22 at 00:28 +0200, Peter Zijlstra wrote:
> On Tue, Jun 21, 2016 at 06:23:34PM -0400, Rik van Riel wrote:
> >
> > > > + /*
> > > > + * Softirq context may get interrupted by hardirq
> > > > context,
> > > > + * on the same CPU. At softirq entry time the amount
>
On Tue, 2016-06-21 at 23:49 +0200, Peter Zijlstra wrote:
> On Thu, Jun 16, 2016 at 12:06:07PM -0400, r...@redhat.com wrote:
> >
> > @@ -53,36 +56,72 @@ DEFINE_PER_CPU(seqcount_t, irq_time_seq);
> > * softirq -> hardirq, hardirq -> softirq
> > *
> > * When exiting hardirq or softirq time, acc
From: Rik van Riel
Drop local_irq_save/restore from irqtime_account_irq.
Instead, have softirq and hardirq track their time spent
independently, with the softirq code subtracting hardirq
time that happened during the duration of the softirq run.
The softirq code can be interrupted by hardirq cod
From: Rik van Riel
Drop local_irq_save/restore from irqtime_account_irq.
Instead, have softirq and hardirq track their time spent
independently, with the softirq code subtracting hardirq
time that happened during the duration of the softirq run.
The softirq code can be interrupted by hardirq cod
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