From: Andi Kleen <ak@suse.de>
To: Andrea Arcangeli <andrea@cpushare.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>
Subject: Re: disable tsc with seccomp
Date: Sat, 5 Nov 2005 17:12:09 +0100 [thread overview]
Message-ID: <200511051712.09280.ak@suse.de> (raw)
In-Reply-To: <20051105160720.GB14064@opteron.random>
On Saturday 05 November 2005 17:07, Andrea Arcangeli wrote:
> On Sat, Nov 05, 2005 at 04:37:44PM +0100, Andi Kleen wrote:
> > It was useless, you can get exactly the same information by using RDPMC
> > on perfctr 0 which always runs the NMI watchdog and counts all cycles
> > too.
>
> nmi watchdog is off in my system, but it was used to be very slow.
It is normally on on all x86-64 systems.
> Anyway performance counters should be turned off too. They can be turned
> off on a per task basis right? Just switching another cr4 bit or what?
I definitely don't want any code like this in the context switch. It is
critical and I don't want to pollute fast paths with stuff like this
that nobody needs.
-Andi
next prev parent reply other threads:[~2005-11-05 16:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-05 13:47 disable tsc with seccomp Andrea Arcangeli
2005-11-05 15:37 ` Andi Kleen
2005-11-05 16:07 ` Andrea Arcangeli
2005-11-05 16:12 ` Andi Kleen [this message]
2005-11-05 16:31 ` Andrea Arcangeli
2005-11-05 17:04 ` Andi Kleen
2005-11-06 1:55 ` Andrea Arcangeli
2005-11-21 16:43 ` Andrea Arcangeli
2005-11-21 17:05 ` Andi Kleen
2005-11-21 17:16 ` Andrea Arcangeli
2005-11-21 17:24 ` Andi Kleen
2005-11-21 17:38 ` Andrea Arcangeli
2005-11-21 18:40 ` Andrea Arcangeli
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