From: "H. Peter Anvin" <hpa@zytor.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Arjan van de Ven <arjan@infradead.org>,
Dan Magenheimer <dan.magenheimer@oracle.com>,
Thomas Gleixner <tglx@linutronix.de>,
Venkatesh Pallipadi <venki@google.com>,
Ingo Molnar <mingo@elte.hu>,
chris.mason@oracle.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: Export tsc related information in sysfs
Date: Tue, 18 May 2010 09:40:47 -0700 [thread overview]
Message-ID: <4BF2C30F.6030502@zytor.com> (raw)
In-Reply-To: <1274183935.5605.7726.camel@twins>
On 05/18/2010 04:58 AM, Peter Zijlstra wrote:
> On Tue, 2010-05-18 at 13:25 +0200, Andi Kleen wrote:
>> On Tue, May 18, 2010 at 11:58:18AM +0200, Peter Zijlstra wrote:
>>> On Sun, 2010-05-16 at 22:06 -0700, Arjan van de Ven wrote:
>>>> look we're not disabling ring 3 tsc. We could, but we don't.
>>>
>>> Maybe we should.
>>
>> That would kill the vsyscall too. Remember it's running in ring 3.
>>
>> That is in theory you could disable it on systems where the vsyscall
>> doesn't use it, but then you would likely break huge amounts of software,
>> unless you emulate it.
>
> Well, software shouldn't use it, so breaking it sounds like a fine
> idea ;-)
>
> Also, a slow emulation is an incentive to actually do the right thing.
The problem is that you throw the baby (vsyscall) out with the bathwater
(user rdtsc).
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2010-05-18 16:45 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
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 [this message]
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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