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From: Wladislav Wiebe <wladislav.wiebe@nokia.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: anna-maria@linutronix.de, frederic@kernel.org, mingo@kernel.org,
	tglx@linutronix.de, akpm@linux-foundation.org,
	bigeasy@linutronix.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] irq: add support for warning on long-running IRQ handlers
Date: Mon, 30 Jun 2025 15:59:17 +0200	[thread overview]
Message-ID: <c77690ff-9f3d-4ab8-9443-b377134e90ca@nokia.com> (raw)
In-Reply-To: <20250630132517.GM1613376@noisy.programming.kicks-ass.net>


On 30/06/2025 15:25, Peter Zijlstra wrote:
> CAUTION: This is an external email. Please be very careful when clicking links or opening attachments. See the URL nok.it/ext for additional information.
>
>
>
> On Mon, Jun 30, 2025 at 02:46:44PM +0200, Wladislav Wiebe wrote:
>> Introduce a new option CONFIG_IRQ_LATENCY_WARN that enables warnings when
>> IRQ handlers take an unusually long time to execute.
>>
>> When triggered, the warning includes the CPU, IRQ number, handler address,
>> name, and execution duration, for example:
>>
>>   [CPU0] latency on IRQ[787:bad_irq_handler+0x1/0x34 [bad_irq]], took: 5 jiffies (~50 ms)
>>
>> To keep runtime overhead minimal, this implementation uses a jiffies-based
>> timing mechanism. While coarse, it is sufficient to detect problematic IRQs.
> local_clock() was found to be excessively expensive?

Perhaps not excessively expensive, but jiffies is the lowest-overhead option here, isn't it?


  reply	other threads:[~2025-06-30 13:59 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-30 12:46 Wladislav Wiebe
2025-06-30 13:25 ` Peter Zijlstra
2025-06-30 13:59   ` Wladislav Wiebe [this message]
2025-07-02  9:06     ` Peter Zijlstra
2025-07-02  9:14       ` Wladislav Wiebe
2025-06-30 15:42 ` Thomas Gleixner
2025-07-01  6:10   ` Wladislav Wiebe
2025-07-01  7:37     ` Thomas Gleixner
2025-07-15  8:23       ` Wladislav Wiebe

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