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From: Ingo Molnar <mingo@elte.hu>
To: Sitsofe Wheeler <sitsofe@yahoo.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Arjan van de Ven <arjan@infradead.org>,
	linux-kernel@vger.kernel.org,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: How how latent should non-preemptive scheduling be?
Date: Tue, 23 Sep 2008 13:53:23 +0200	[thread overview]
Message-ID: <20080923115323.GA27240@elte.hu> (raw)
In-Reply-To: <48D88DB4.9020003@yahoo.com>

* Sitsofe Wheeler <sitsofe@yahoo.com> wrote:

> Ingo Molnar wrote:
>> well, since they went away after you enabled CONFIG_PREEMPT=y, they are 
>> definitely in-kernel latencies, not any external SMM latencies.
>>
>> I.e. they are inherently fixable. Could you enable:
>>
>>   CONFIG_DYNAMIC_FTRACE=y
>>   CONFIG_FTRACE_MCOUNT_RECORD=y
>>
>> that should make the traces a lot more verbose - every kernel function  
>> executed in the latency path will be logged. That way we'll be able to  
>> say which one takes that long.
>
> I do not appear to have the CONFIG_FTRACE_MCOUNT_RECORD option in 
> 2.6.27rc7. Is it an option that is only in -tip ?

yeah - it's a new ftrace feature queued up for v2.6.28.

	Ingo

  reply	other threads:[~2008-09-23 11:53 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.ERZTl/6uH+mhNoef5fPJKTRjJag@ifi.uio.no>
     [not found] ` <fa.PtPFzP5kIJVCCov6YCewrh+o4z4@ifi.uio.no>
     [not found]   ` <fa.C6WSm5Rh2Nb+Qho7b0qDOZ9RPV8@ifi.uio.no>
     [not found]     ` <fa.ch6j4qXs/2sFpLkHz5fXrtjTR8c@ifi.uio.no>
     [not found]       ` <fa.Jx/Ygtm46CVRawlA6OnfYNn6cN0@ifi.uio.no>
2008-09-18  7:26         ` Sitsofe Wheeler
     [not found]         ` <fa.iIHgL48F3T5VAqFw3mqaf9Pzrs4@ifi.uio.no>
     [not found]           ` <fa.Td8xkKZKMSMghlJmEYefTRVF2kc@ifi.uio.no>
2008-09-19 11:54             ` Sitsofe Wheeler
2008-09-19 14:20               ` Peter Zijlstra
2008-09-22 11:57               ` Ingo Molnar
2008-09-22 12:07                 ` Steven Rostedt
2008-09-23  6:33                 ` Sitsofe Wheeler
2008-09-23 11:53                   ` Ingo Molnar [this message]
2008-09-23 16:30                     ` Sitsofe Wheeler
2008-09-23 19:39                       ` Sitsofe Wheeler
2008-09-23 22:01                         ` Sitsofe Wheeler
2008-09-27 20:48                           ` Ingo Molnar
2008-09-28 20:56                             ` Sitsofe Wheeler
2008-09-29  8:37                               ` Ingo Molnar
2008-09-29 23:11                                 ` Sitsofe Wheeler
2008-09-30 11:22                                   ` Ingo Molnar
2008-09-30 13:18                                     ` Sitsofe Wheeler
2008-10-04 10:50                                       ` Reading EeePC900 battery info causes stalls when using SLUB (was Re: How how latent should non-preemptive scheduling be?) Sitsofe Wheeler
     [not found] <fa.vMKgvqjqmYnI2J40GHoTENeYm8U@ifi.uio.no>
     [not found] ` <fa.808p0ZtU9DCpeky4KfNS8Drdw9w@ifi.uio.no>
2008-09-17 21:48   ` How how latent should non-preemptive scheduling be? Sitsofe Wheeler
2008-09-17 21:54     ` Arjan van de Ven
2008-09-17 22:29       ` Sitsofe Wheeler
2008-09-18  2:42       ` Peter Zijlstra
2008-09-18 18:25         ` Sitsofe Wheeler
2008-09-19  8:44           ` Ingo Molnar
2008-09-17 21:18 Sitsofe Wheeler
2008-09-17 21:28 ` Sitsofe Wheeler
2008-09-17 21:34 ` Arjan van de Ven
2008-09-21 20:56 ` Matt Keenan
2008-09-22  6:50   ` Sitsofe Wheeler

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