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Message-Id: <20080118184620.0D571498027@tavolara.isolaweb.it>
Date: Fri, 18 Jan 2008 19:46:22 +0100
From: Roberto Fichera <kernel@...no-soft.it>
To: Arjan van de Ven <arjan@...ux.intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...e.hu>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [Announce] Development release 0.1 of the LatencyTOP tool
At 19.35 18/01/2008, Arjan van de Ven wrote:
>Roberto Fichera wrote:
>> At 18.36 18/01/2008, Arjan van de Ven wrote:
>>> The Intel Open Source Technology Center is pleased to announce the
>>> release of version 0.1 of LatencyTOP, a tool for developers to visualize
>>> system latencies.
>>>
>>> http://www.latencytop.org
>>>
>>
>> [...snip...]
>>
>>> The most basic annotation looks like this (in the patches more complex
>>> versions can be seen):
>>>
>>> asmlinkage long sys_sync(void)
>>> {
>>> + struct latency_entry reason;
>>> + set_latency_reason("sync system call", &reason);
>>> do_sync(1);
>>> + restore_latency_reason(&reason);
>>> +
>>> return 0;
>>> }
>>>
>>
>> I really like this patch :-)! Just a little note, why don't make
>> the parameter 'char *reason' as simple integer (reason_t)?
>> Making it as integer will automatically drop the strncmp()
>> and speeding up all the things. Could be also interesting to
>> define _externally_ the mapping of the reason so the
>> userspace tool could handle it easily.
>>
>
>I thought about that, but the strncmp is still somewhat needed to deal
>with the argument
>(the instrumentation above doesn't use that, but the mutex one does
>for example)
>If we get rid of the argument entirely it'd be easier
>(but then we get "blocking on mutex" rather than "blocking on inode->mutex")
Duh! I didn't notice it! Now I see ;-)!
>
Roberto Fichera.
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