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From: Nikanth Karthikesan <knikanth@suse.de>
To: Guillaume Chazarain <guichaz@gmail.com>
Cc: balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org,
	procps-feedback@lists.sf.net,
	Albert Cahalan <albert@users.sf.net>
Subject: Re: [PATCH 1/3] taskstats-fork: Add a new taskstats command to get notification on fork/clone
Date: Mon, 31 Aug 2009 14:41:28 +0530	[thread overview]
Message-ID: <200908311441.28354.knikanth@suse.de> (raw)
In-Reply-To: <3d8471ca0908301252j15cb33b1j913921bd8fc6704c@mail.gmail.com>

On Monday 31 August 2009 01:22:22 Guillaume Chazarain wrote:
> On Tue, Jul 21, 2009 at 8:24 AM, Nikanth Karthikesan<knikanth@suse.de> 
wrote:
> > Ah.. proc-events was the exact thing, I was looking for! Thanks.
>
> AFAICT proc-events can only be used by root, so that makes it
> unsuitable for *top.
>
> Anyway, iotop will always have to iterate over all threads to query
> their taskstats and other attributes, so the O(nr_threads) complexity
> is unavoidable.
>

If it would simply iterate over all the current threads, the complexity would 
be O(nr_threads). But while iterating through all the current threads, it 
checks whether it is a new thread or a known thread, so that it can calculate 
the delta values. This is what I optimized by using taskstats-fork, which 
could be optimized using proc-events. 

Thanks
Nikanth

      parent reply	other threads:[~2009-08-31  9:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-21  5:01 [PATCH 1/3] taskstats-fork: Add a new taskstats command to get notification on fork/clone Nikanth Karthikesan
2009-07-21  6:01 ` Balbir Singh
2009-07-21  6:24   ` Nikanth Karthikesan
2009-08-30 19:52     ` Guillaume Chazarain
2009-08-31  5:26       ` Balbir Singh
2009-08-31  9:11       ` Nikanth Karthikesan [this message]

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