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Date: Sat, 17 Feb 2007 15:56:55 +0100
From: Andi Kleen <andi@firstfloor.org>
To: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>, Jeff Muizelaar <jeff@infidigm.net>,
       linux-kernel@vger.kernel.org
Subject: Re: Using sched_clock for mmio-trace
Message-ID: <20070217145655.GA15662@one.firstfloor.org>
References: <20070216013024.GA32287@infidigm.net> <y0mr6sq2hfj.fsf@ton.toronto.redhat.com> <p73fy95g99w.fsf@bingen.suse.de> <20070216212630.GC27135@redhat.com>
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> This is one of the reasons why we don't just use good old
> do_gettimeofday(), since it takes locks and can lead to lock recursion
> if parts of itself are probed.

do_gettimeofday doesn't take locks.

Only restriction is that you can't single step it with long 
pauses between instructions.

-Andi