From: Frans Pop <elendil@planet.nl>
To: Luming Yu <luming.yu@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC patch] reset TSC at the begining of check_tsc_warp
Date: Tue, 2 Jun 2009 01:10:05 +0200 [thread overview]
Message-ID: <200906020110.06135.elendil@planet.nl> (raw)
In-Reply-To: <3877989d0906010201j438a08a8x559f62b0aed40696@mail.gmail.com>
Luming Yu wrote:
> Without this patch, we always get kernel warning that TSC warp between
> CPUs, and TSC is marked unstable due to check_tsc_sync_source failed if
> the CPUs have the problem of not-synced initial TSC.
>
> It hurts CPUs with constant-tsc feature, but with unsynced initial TSC
> value...
>
> The downside is we could break perfect synced TSC with this patch.
> Please review, test and apply.
I've tested this on my desktop (working TSC) and my laptop (non-working TSC).
On both machines the patch didn't make any difference.
Desktop: Intel mainboard, ICH7 chipset, dual core Pentium D 3.20GHz
$ dmesg | grep -i tsc
Fast TSC calibration using PIT
checking TSC synchronization [CPU#0 -> CPU#1]: passed.
Laptop: HP 2510p notebook, ICH8 chipset, Core2 Duo 1.33GHz
$ dmesg | grep -i tsc
Fast TSC calibration using PIT
checking TSC synchronization [CPU#0 -> CPU#1]: passed.
Marking TSC unstable due to TSC halts in idle
Clocksource tsc unstable (delta = -98164364 ns)
Tested on top of today's mainline git.
Cheers,
FJP
next prev parent reply other threads:[~2009-06-01 23:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-01 9:01 [RFC patch] reset TSC at the begining of check_tsc_warp Luming Yu
2009-06-01 23:10 ` Frans Pop [this message]
2009-06-02 7:05 ` Luming Yu
2009-06-02 7:54 ` Andi Kleen
2009-06-02 8:28 ` Luming Yu
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