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Date: Sat, 9 May 2009 12:01:37 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>,
       Steven Rostedt <rostedt@goodmis.org>,
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       Alexey Dobriyan <adobriyan@gmail.com>,
       "linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [patch] tracing/mm: add page frame snapshot trace
Message-ID: <20090509100137.GC20941@elte.hu>
References: <20090508105320.316173813@intel.com> <20090508111031.020574236@intel.com> <20090508114742.GB17129@elte.hu> <20090508124433.GB15949@localhost> <20090509062758.GB21354@elte.hu> <20090509091325.GA7994@localhost>
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* Wu Fengguang <fengguang.wu@intel.com> wrote:

> 2) support concurrent object iterations
>    For example, a huge 1TB memory space can be split up into 10
>    segments which can be queried concurrently (with different options).

this should already be possible. If you lseek the trigger file, that 
will be understood as an 'offset' by the patch, and then write a 
(decimal) value into the file, that will be the count.

So it should already be possible to fork off nr_cpus helper threads, 
one bound to each CPU, each triggering trace output of a separate 
segment of the memory map - and each reading that CPU's 
trace_pipe_raw file to recover the data - all in parallel.

	Ingo