From: khilman@deeprootsystems•com (Kevin Hilman)
To: linux-arm-kernel@lists•infradead.org
Subject: RT throttling and suspend/resume (was Re: [PATCH] i2c: omap: revert "i2c: omap: switch to threaded IRQ support")
Date: Mon, 22 Oct 2012 09:47:06 -0700 [thread overview]
Message-ID: <87ehkqihdh.fsf@deeprootsystems.com> (raw)
In-Reply-To: <1350899541.2768.82.camel@twins> (Peter Zijlstra's message of "Mon, 22 Oct 2012 11:52:21 +0200")
Peter Zijlstra <peterz@infradead•org> writes:
> On Fri, 2012-10-19 at 16:54 -0700, Kevin Hilman wrote:
>
>> So I did the same thing for my ARM SoC, and it definitley stops the RT
>> throttling.
>>
>> However, it has the undesriable (IMO) side effect of making timed printk
>> output rather unhelpful for debugging suspend/resume since printk time
>> stays constant throughout suspend/resume no matter how long you
>> sleep. :(
>>
>> So does that mean we have to choose between useful printk times during
>> suspend/resume or functioning IRQ threads during suspend/resume ?
>
> Urgh.. this was not something I considered. This being primarily the
> sched_clock infrastructure and such.
>
> So what exactly is the problem with the suspend resume thing (its not
> something I've ever debugged), is all you need a clean break between pre
> and post suspend, or do you need the actual time the machine was gone?
I think it's more a question of what people are used to. I think folks
used to debugging suspend/resume (at least on ARM) are used to having
the printk timestamps reflect the amount of time the machine was gone.
With a sched_clock() that counts during suspend, that feature doesn't
work anymore. I'm not sure that this feature is a deal breaker, but it
has been convenient. I see that on x86, it's already normal that
printk times don't reflect time spent in suspend, so I guess ARM needs
to adapt.
Kevin
next prev parent reply other threads:[~2012-10-22 16:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-15 1:51 [PATCH] i2c: omap: revert "i2c: omap: switch to threaded IRQ support" Paul Walmsley
2012-10-15 7:16 ` Felipe Balbi
2012-10-15 15:05 ` Paul Walmsley
2012-10-16 12:58 ` Shubhrajyoti Datta
2012-10-16 13:33 ` Felipe Balbi
2012-10-16 13:37 ` Felipe Balbi
2012-10-16 21:39 ` RT throttling and suspend/resume (was Re: [PATCH] i2c: omap: revert "i2c: omap: switch to threaded IRQ support") Kevin Hilman
2012-10-17 14:00 ` Felipe Balbi
2012-10-17 14:41 ` Felipe Balbi
2012-10-17 23:06 ` Kevin Hilman
2012-10-18 5:51 ` Felipe Balbi
2012-10-19 14:00 ` Peter Zijlstra
2012-10-19 16:30 ` Felipe Balbi
2012-10-19 23:28 ` Kevin Hilman
2012-10-19 23:54 ` Kevin Hilman
2012-10-22 9:52 ` Peter Zijlstra
2012-10-22 16:47 ` Kevin Hilman [this message]
2012-10-23 9:19 ` Russell King - ARM Linux
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