From: Andi Kleen <andi@firstfloor.org>
To: Venkatesh Pallipadi <venki@google.com>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Chris Mason <chris.mason@oracle.com>,
linux-kernel@vger.kernel.org,
Dan Magenheimer <dan.magenheimer@oracle.com>
Subject: Re: [PATCH] x86: Export tsc related information in sysfs
Date: Sat, 15 May 2010 11:57:04 +0200 [thread overview]
Message-ID: <87tyq9mqrz.fsf@basil.nowhere.org> (raw)
In-Reply-To: <1273887635-27610-1-git-send-email-venki@google.com> (Venkatesh Pallipadi's message of "Fri\, 14 May 2010 18\:40\:35 -0700")
Venkatesh Pallipadi <venki@google.com> writes:
> From: Dan Magenheimer <dan.magenheimer@oracle.com>
>
> Kernel information about calibrated value of tsc_khz and
> tsc_stability (result of tsc warp test) are useful bits of information
> for any app that wants to use TSC directly. Export this read_only
> information in sysfs.
Is this really a good idea? It will encourage the applications
to use RDTSC directly, but there are all kinds of constraints on
that. Even the kernel has a hard time with them, how likely
is it that applications will get all that right?
It would be better to fix them to use the vsyscalls instead.
Or if they can't use the vsyscalls for some reason today fix them.
This way if anything changes again in TSC the kernel could
shield the applications.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-05-15 9:57 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-15 1:40 [PATCH] x86: Export tsc related information in sysfs Venkatesh Pallipadi
2010-05-15 9:57 ` Andi Kleen [this message]
2010-05-15 13:29 ` Dan Magenheimer
2010-05-15 16:48 ` Venkatesh Pallipadi
2010-05-15 19:14 ` Arjan van de Ven
2010-05-15 22:32 ` Dan Magenheimer
2010-05-16 5:43 ` Arjan van de Ven
2010-05-16 9:20 ` Thomas Gleixner
2010-05-16 16:42 ` Dan Magenheimer
2010-05-16 19:14 ` Thomas Gleixner
2010-05-17 1:31 ` Dan Magenheimer
2010-05-17 5:06 ` Arjan van de Ven
2010-05-18 9:58 ` Peter Zijlstra
2010-05-18 10:03 ` Peter Zijlstra
2010-05-18 11:25 ` Andi Kleen
2010-05-18 11:58 ` Peter Zijlstra
2010-05-18 15:13 ` Dan Magenheimer
2010-05-18 16:40 ` H. Peter Anvin
2010-05-18 16:52 ` Peter Zijlstra
2010-05-18 17:04 ` H. Peter Anvin
2010-05-18 17:49 ` Dan Magenheimer
2010-05-18 18:46 ` H. Peter Anvin
2010-05-18 19:00 ` Dan Magenheimer
2010-05-18 19:16 ` Dan Magenheimer
2010-05-18 19:26 ` H. Peter Anvin
2010-05-18 20:29 ` Dan Magenheimer
2010-05-18 20:34 ` H. Peter Anvin
2010-05-18 21:02 ` Dan Magenheimer
2010-05-18 21:13 ` Andi Kleen
2010-05-19 6:26 ` Peter Zijlstra
2010-05-17 10:20 ` Thomas Gleixner
2010-05-16 20:29 ` Arjan van de Ven
2010-05-17 10:26 ` Andi Kleen
2010-06-04 14:24 ` Pavel Machek
2010-05-15 22:45 ` Thomas Gleixner
2010-05-17 10:22 ` Andi Kleen
2010-05-17 15:23 ` Dan Magenheimer
2010-05-17 16:56 ` Andi Kleen
2010-05-17 22:36 ` Thomas Gleixner
2010-05-17 23:33 ` Dan Magenheimer
2010-05-18 0:00 ` Ingo Molnar
2010-05-18 0:02 ` Ingo Molnar
2010-05-15 12:35 ` Jaswinder Singh Rajput
2010-05-15 14:37 ` Venkatesh Pallipadi
-- strict thread matches above, loose matches on Subject: below --
2010-05-20 19:19 Brian Bloniarz
2010-05-22 2:03 ` john stultz
2010-05-22 3:33 ` H. Peter Anvin
2010-05-24 18:13 ` Dan Magenheimer
2010-05-24 18:19 ` H. Peter Anvin
2010-05-24 18:51 ` john stultz
2010-05-24 20:20 ` H. Peter Anvin
2010-05-24 20:39 ` john stultz
2010-05-24 21:26 ` H. Peter Anvin
2010-05-24 22:04 ` Dan Magenheimer
2010-05-24 22:30 ` H. Peter Anvin
2010-05-24 22:49 ` john stultz
2010-05-24 23:16 ` Dan Magenheimer
2010-05-24 23:19 ` H. Peter Anvin
2010-05-24 23:30 ` john stultz
2010-05-24 23:42 ` Andi Kleen
2010-05-25 0:01 ` Dan Magenheimer
2010-05-25 0:07 ` H. Peter Anvin
2010-05-25 1:33 ` Brian Bloniarz
2010-05-26 0:16 ` Brian Bloniarz
2010-05-26 0:48 ` john stultz
2010-05-26 2:50 ` Brian Bloniarz
2010-05-26 12:35 ` Thomas Gleixner
2010-05-26 14:26 ` Dan Magenheimer
2010-05-26 14:41 ` Thomas Gleixner
2010-05-26 15:04 ` john stultz
2010-05-26 16:02 ` Brian Bloniarz
2010-05-26 16:25 ` john stultz
2010-05-26 18:24 ` H. Peter Anvin
2010-05-26 18:44 ` Brian Bloniarz
2010-05-26 18:51 ` H. Peter Anvin
2010-05-26 20:19 ` john stultz
2010-05-26 21:06 ` H. Peter Anvin
2010-05-26 19:49 ` john stultz
2010-05-26 20:22 ` Brian Bloniarz
2010-05-26 12:30 ` Thomas Gleixner
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