From: Andi Kleen <ak@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>,
Arjan van de Ven <arjan@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [patch] x86: unify/rewrite SMP TSC sync code
Date: Fri, 24 Nov 2006 18:13:13 +0100 [thread overview]
Message-ID: <200611241813.13205.ak@suse.de> (raw)
In-Reply-To: <20061124170246.GA9956@elte.hu>
> make the TSC synchronization code more robust, and unify it between
> x86_64 and i386.
>
> The biggest change is the removal of the 'fix up TSCs' code on x86_64
> and i386, in some rare cases it was /causing/ time-warps on SMP systems.
On x86-64 I don't think it can since it doesn't check anymore on sync Intel.
> The new code only checks for TSC asynchronity - and if it can prove a
> time-warp (if it can observe the TSC going backwards when going from one
> CPU to another within a critical section), then the TSC clock-source is
> turned off.
The trouble is that people are using the RDTSC anyways even if the
kernel doesn't. So some synchronization is probably a good idea.
-Andi
next prev parent reply other threads:[~2006-11-24 17:13 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-24 17:02 [patch] x86: unify/rewrite SMP TSC sync code Ingo Molnar
2006-11-24 17:13 ` Andi Kleen [this message]
2006-11-24 20:25 ` Ingo Molnar
2006-11-24 20:37 ` Andi Kleen
2006-11-24 20:46 ` Ingo Molnar
2006-11-24 21:06 ` Andi Kleen
2006-11-24 22:48 ` Ben Greear
2006-11-25 2:56 ` Wink Saville
2006-11-25 8:30 ` Arjan van de Ven
2006-11-25 16:58 ` Wink Saville
2006-11-25 17:41 ` Arjan van de Ven
2006-11-25 20:34 ` Wink Saville
2006-11-27 19:00 ` Christoph Lameter
2006-11-29 7:13 ` Ingo Molnar
[not found] <fa./NRPJg+JjfSQLUVwnX1GpHGIojQ@ifi.uio.no>
[not found] ` <fa.Y0RKABHd+7qnbGQYBAGPvlJ0Qic@ifi.uio.no>
[not found] ` <fa.fD3WSpNqEJ4736vYzEak5Gf3xTw@ifi.uio.no>
[not found] ` <fa.A+gkQAO1DLThaxJxPLPl3yE1CGo@ifi.uio.no>
[not found] ` <fa.INurNKWdUKAEULTHyfpSW65a/Ng@ifi.uio.no>
[not found] ` <fa.n9vySiI9RS2MCl0DZPDzxZEPiFw@ifi.uio.no>
2006-11-26 7:20 ` Robert Hancock
2006-11-26 8:16 ` Wink Saville
2006-11-26 8:24 ` Arjan van de Ven
2006-11-26 19:48 ` Wink Saville
2006-11-27 7:51 ` Arjan van de Ven
2006-11-27 9:15 ` Wink Saville
-- strict thread matches above, loose matches on Subject: below --
2006-11-27 17:23 Robert Crocombe
2006-11-27 18:41 ` Max Krasnyansky
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