From: Dave Hansen <dave.hansen@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org,
tglx@linutronix.de, dzickus@redhat.com,
linux-tip-commits@vger.kernel.org
Subject: Re: [tip:perf/core] x86/nmi: Push duration printk() to irq context
Date: Tue, 11 Feb 2014 08:44:22 -0800 [thread overview]
Message-ID: <52FA5366.3020007@linux.intel.com> (raw)
In-Reply-To: <20140211150116.GO27965@twins.programming.kicks-ass.net>
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.
next prev parent reply other threads:[~2014-02-11 16:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-10 13:29 [tip:perf/core] x86/nmi: Push duration printk() to irq context tip-bot for Peter Zijlstra
2014-02-10 16:45 ` Dave Hansen
2014-02-10 17:05 ` Peter Zijlstra
2014-02-11 15:01 ` Peter Zijlstra
2014-02-11 16:44 ` Dave Hansen [this message]
2014-02-21 21:12 ` [tip:perf/core] perf/x86: Warn to early_printk() in case irq_work is too slow tip-bot for Peter Zijlstra
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