Re: [PATCH v5 1/2] perf: use hrtimer for event multiplexing

From: Peter Zijlstra
Date: Mon Mar 25 2013 - 07:13:49 EST


On Fri, 2013-03-22 at 11:51 +0100, Stephane Eranian wrote:
> +#define PERF_CPU_HRTIMER (1000 / HZ)
> +static enum hrtimer_restart perf_cpu_hrtimer_handler(struct hrtimer
> *hr)
> +{
> + struct perf_cpu_context *cpuctx;
> + enum hrtimer_restart ret = HRTIMER_NORESTART;
> + unsigned long flags;
> + int rotations = 0;
> +
> + cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
> +
> + local_irq_save(flags);
> +
> + rotations = perf_rotate_context(cpuctx);
> +
> + local_irq_restore(flags);

IIRC hrtimer callbacks are always ran with interrupts disabled.. not a
big deal though. I'll continue reading.

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