Date: Thu, 27 Nov 2008 03:42:47 -0800 (PST)
Message-Id: <20081127.034247.72331360.davem@davemloft.net>
To: eranian@gmail.com, eranian@googlemail.com
Cc: andi@firstfloor.org, tglx@linutronix.de, linux-kernel@vger.kernel.org,
       akpm@linux-foundation.org, mingo@elte.hu, x86@kernel.org,
       sfr@canb.auug.org.au
Subject: Re: [patch 05/24] perfmon: X86 generic code (x86)
From: David Miller <davem@davemloft.net>
In-Reply-To: <7c86c4470811270335p2dbd61ebpe2c584e32d8b2292@mail.gmail.com>
References: <7c86c4470811270209q18d4e83aq8901837159838cc4@mail.gmail.com>
	<20081127113115.GH6703@one.firstfloor.org>
	<7c86c4470811270335p2dbd61ebpe2c584e32d8b2292@mail.gmail.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 778
Lines: 18

From: "stephane eranian" <eranian@googlemail.com>
Date: Thu, 27 Nov 2008 12:35:54 +0100

> I am still wondering how Oprofile handles the case where multiple
> processes or threads access the same file descriptor.

There's only one profiling buffer active on a given cpu,
so it's pure per-cpu value insertion.

In any event I think that NMI profiling is a must, especially
for the kernel.  You get total unusable crap otherwise.  I
just learned this the hard way having gotten an NMI'ish scheme
working on sparc64 just the other day.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/