Re: [tip:perf/core] x86/nmi: Push duration printk() to irq context

From: Dave Hansen
Date: Tue Feb 11 2014 - 11:44:37 EST


On 02/11/2014 07:01 AM, Peter Zijlstra wrote:
> - irq_work_queue(&perf_duration_work);
> + if (!irq_work_queue(&perf_duration_work)) {
> + early_printk("perf interrupt took too long (%lld > %lld), lowering "
> + "kernel.perf_event_max_sample_rate to %d\n",
> + avg_local_sample_len, allowed_ns >> 1,
> + sysctl_perf_event_sample_rate);
> + }
> }

That's a cool trick. Works for me.
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