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Message-ID: <1285844768.2144.11.camel@laptop>
Date: Thu, 30 Sep 2010 13:06:08 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Venkatesh Pallipadi <venki@...gle.com>
Cc: Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Balbir Singh <balbir@...ux.vnet.ibm.com>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
linux-kernel@...r.kernel.org, Paul Turner <pjt@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH 3/7] Add IRQ_TIME_ACCOUNTING, finer accounting of irq
time -v3
On Wed, 2010-09-29 at 12:21 -0700, Venkatesh Pallipadi wrote:
> +void account_system_vtime(struct task_struct *curr)
> +{
> + unsigned long flags;
> + int cpu;
> + u64 now, delta;
> +
> + if (!sched_clock_irqtime)
> + return;
> +
> + local_irq_save(flags);
> +
> + now = sched_clock();
> + cpu = smp_processor_id();
Like said before, that really wants to read like:
cpu = smp_processor_id();
now = sched_clock_cpu(cpu);
sched_clock() is raw tsc + ns conversion and can go all over the place.
> + delta = now - per_cpu(irq_start_time, cpu);
> + per_cpu(irq_start_time, cpu) = now;
> + if (hardirq_count())
> + per_cpu(cpu_hardirq_time, cpu) += delta;
> + else if (in_serving_softirq())
> + per_cpu(cpu_softirq_time, cpu) += delta;
> +
> + local_irq_restore(flags);
> +}
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