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From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: tglx@linutronix.de, shreyas@linux.vnet.ibm.com,
	linux-kernel@vger.kernel.org, peterz@infradead.org,
	rafael@kernel.org, vincent.guittot@linaro.org
Subject: Re: [PATCH V6] irq: Track the interrupt timings
Date: Tue, 14 Jun 2016 16:38:06 -0400 (EDT)	[thread overview]
Message-ID: <alpine.LFD.2.20.1606141636510.1714@knanqh.ubzr> (raw)
In-Reply-To: <1465935043-4844-1-git-send-email-daniel.lezcano@linaro.org>

On Tue, 14 Jun 2016, Daniel Lezcano wrote:

> The interrupt framework gives a lot of information about each interrupt.
> 
> It does not keep track of when those interrupts occur though.
> 
> This patch provides a mean to record the elapsed time between successive
> interrupt occurrences in a per-IRQ per-CPU circular buffer to help with the
> prediction of the next occurrence using a statistical model.
> 
> A new function is added to browse the different interrupts and retrieve the
> timing information stored in it.
> 
> A static key is introduced so when the irq prediction is switched off at
> runtime, we can reduce the overhead near to zero. The irq timings is
> supposed to be potentially used by different sub-systems and for this reason
> the static key is a ref counter, so when the last use releases the irq
> timings that will result on the effective deactivation of the irq measurement.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
> ---
> V6:
>   - Renamed handle_irq_timings to record_irq_time
>   - Stored the event time instead of the interval time
>   - Removed the 'timestamp' field from the timings structure
>   - Moved _handle_irq_timings content inside record_irq_time

Looks fine to me.


Nicolas

  reply	other threads:[~2016-06-14 20:38 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-14 16:33 [PATCH V5] irq: Track the interrupt timings Daniel Lezcano
2016-06-14 17:46 ` Nicolas Pitre
2016-06-14 18:11   ` Thomas Gleixner
2016-06-14 19:52     ` Daniel Lezcano
2016-06-14 20:10     ` [PATCH V6] " Daniel Lezcano
2016-06-14 20:38       ` Nicolas Pitre [this message]
2016-06-17 13:46       ` Thomas Gleixner
2016-06-17 17:16         ` [PATCH V7] " Daniel Lezcano
2016-06-23  8:41           ` Thomas Gleixner
2016-06-23  9:39             ` Daniel Lezcano
2016-06-23 10:12               ` Thomas Gleixner
2016-06-23 13:12                 ` Daniel Lezcano

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