From: Jindrich Makovicka <makovick@kmlinux.fjfi.cvut.cz>
To: linux-kernel@vger.kernel.org
Subject: Re: Hyper-Threading Vulnerability
Date: Sat, 14 May 2005 19:04:29 +0200 [thread overview]
Message-ID: <d65b2m$atq$1@sea.gmane.org> (raw)
In-Reply-To: <1116088229.8880.7.camel@mindpipe>
Lee Revell wrote:
> On Sat, 2005-05-14 at 16:23 +0100, Alan Cox wrote:
>
>>On Sad, 2005-05-14 at 00:38, Lee Revell wrote:
>>
>>>Well yes but you would still have to recompile those apps. And take the
>>>big performance hit from using gettimeofday vs rdtsc. Disabling HT by
>>>default looks pretty good by comparison.
>>
>>You cannot use rdtsc for anything but rough instruction timing. The
>>timers for different processors run at different speeds on some SMP
>>systems, the timer rates vary as processors change clock rate nowdays.
>>Rdtsc may also jump dramatically on a suspend/resume.
>>
>>If the app uses rdtsc then generally speaking its terminally broken. The
>>only exception is some profiling tools.
>
>
> That is basically all JACK and mplayer use it for. They have RT
> constraints and the tsc is used to know if we got woken up too late and
> should just drop some frames. The developers are aware of the issues
> with rdtsc and have chosen to use it anyway because these apps need
> every ounce of CPU and cannot tolerate the overhead of gettimeofday().
AFAIK, mplayer actually uses gettimeofday(). rdtsc is used in some
places for profiling and debugging purposes and not compiled in by default.
--
Jindrich Makovicka
next prev parent reply other threads:[~2005-05-14 17:05 UTC|newest]
Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-13 5:51 Hyper-Threading Vulnerability Gabor MICSKO
2005-05-13 12:47 ` Barry K. Nathan
2005-05-13 14:10 ` Jeff Garzik
2005-05-13 14:23 ` Daniel Jacobowitz
2005-05-13 14:32 ` Jeff Garzik
2005-05-13 17:13 ` Andy Isaacson
2005-05-13 18:30 ` Vadim Lobanov
2005-05-13 19:02 ` Andy Isaacson
2005-05-15 9:31 ` Adrian Bunk
2005-05-13 17:14 ` Gabor MICSKO
2005-05-13 20:23 ` Barry K. Nathan
2005-05-13 18:03 ` Andi Kleen
2005-05-13 18:34 ` Eric Rannaud
2005-05-13 18:35 ` Alan Cox
2005-05-13 18:49 ` Scott Robert Ladd
2005-05-13 19:08 ` Andi Kleen
2005-05-13 19:36 ` Grant Coady
2005-05-16 17:00 ` Linus Torvalds
2005-05-16 12:37 ` Tommy Reynolds
2005-05-18 19:07 ` Bill Davidsen
2005-05-13 18:38 ` Richard F. Rebel
2005-05-13 19:05 ` Andi Kleen
2005-05-13 21:26 ` Andy Isaacson
2005-05-13 21:59 ` Matt Mackall
2005-05-13 22:47 ` Alan Cox
2005-05-13 23:00 ` Lee Revell
2005-05-13 23:27 ` Dave Jones
2005-05-13 23:38 ` Lee Revell
2005-05-13 23:44 ` Dave Jones
2005-05-14 7:37 ` Lee Revell
2005-05-14 15:33 ` Andrea Arcangeli
2005-05-15 1:07 ` Christer Weinigel
2005-05-15 9:48 ` Andi Kleen
2005-05-14 15:23 ` Alan Cox
2005-05-14 15:45 ` andrea
2005-05-15 13:38 ` Mikulas Patocka
2005-05-16 7:06 ` andrea
2005-05-14 16:30 ` Lee Revell
2005-05-14 16:44 ` Arjan van de Ven
2005-05-14 17:56 ` Lee Revell
2005-05-14 18:01 ` Arjan van de Ven
2005-05-14 19:21 ` Lee Revell
2005-05-14 19:48 ` Arjan van de Ven
2005-05-14 23:40 ` Lee Revell
2005-05-15 7:30 ` Arjan van de Ven
2005-05-15 20:41 ` Alan Cox
2005-05-15 20:48 ` Arjan van de Ven
2005-05-15 21:10 ` Lee Revell
2005-05-15 22:55 ` Dave Jones
2005-05-15 23:10 ` Lee Revell
2005-05-16 7:25 ` Arjan van de Ven
2005-05-15 9:37 ` Andi Kleen
2005-05-15 3:19 ` dean gaudet
2005-05-15 10:01 ` Andi Kleen
2005-05-15 10:23 ` 2.6.4 timer and helper functions kernel
2005-05-19 0:38 ` George Anzinger
2005-05-15 9:33 ` Hyper-Threading Vulnerability Adrian Bunk
2005-05-14 17:04 ` Jindrich Makovicka [this message]
2005-05-14 18:27 ` Lee Revell
2005-05-15 9:58 ` Andi Kleen
2005-05-14 0:39 ` dean gaudet
2005-05-16 13:41 ` Andrea Arcangeli
2005-05-15 9:43 ` Andi Kleen
2005-05-15 18:42 ` David Schwartz
2005-05-15 18:56 ` Dr. David Alan Gilbert
2005-05-16 7:10 ` Eric W. Biederman
2005-05-16 11:04 ` Andi Kleen
2005-05-16 19:14 ` Eric W. Biederman
2005-05-16 20:05 ` Valdis.Kletnieks
2005-05-15 14:00 ` Mikulas Patocka
2005-05-15 14:26 ` Andi Kleen
2005-05-13 23:32 ` Paul Jakma
2005-05-14 16:29 ` Paul Jakma
2005-05-13 19:14 ` Jim Crilly
2005-05-13 20:18 ` Barry K. Nathan
2005-05-13 23:14 ` Jim Crilly
2005-05-13 19:16 ` Diego Calleja
2005-05-13 19:42 ` Frank Denis (Jedi/Sector One)
2005-05-15 9:54 ` Andi Kleen
2005-05-15 13:51 ` Mikulas Patocka
2005-05-15 14:12 ` Andi Kleen
2005-05-15 14:21 ` Mikulas Patocka
2005-05-15 14:52 ` Tomasz Torcz
2005-05-15 15:00 ` Disk write cache (Was: Hyper-Threading Vulnerability) Mikulas Patocka
2005-05-15 15:21 ` Gene Heskett
2005-05-15 15:29 ` Jeff Garzik
2005-05-15 16:27 ` Disk write cache Kenichi Okuyama
2005-05-15 16:43 ` Jeff Garzik
2005-05-15 16:50 ` Kyle Moffett
2005-05-15 16:56 ` Andi Kleen
2005-05-15 20:44 ` Andrew Morton
2005-05-15 23:31 ` Cache based insecurity/CPU cache/Disk Cache Tradeoffs Brian O'Mahoney
2005-05-15 16:58 ` Disk write cache Mikulas Patocka
2005-05-15 17:20 ` Kenichi Okuyama
2005-05-16 11:02 ` Linux does not care for data integrity (was: Disk write cache) Matthias Andree
2005-05-16 11:12 ` Arjan van de Ven
2005-05-16 11:29 ` Matthias Andree
2005-05-16 14:02 ` Arjan van de Ven
2005-05-16 14:48 ` Matthias Andree
2005-05-16 15:06 ` Alan Cox
2005-05-16 15:40 ` Matthias Andree
2005-05-16 18:04 ` Alan Cox
2005-05-16 19:11 ` Linux does not care for data integrity Florian Weimer
2005-05-29 21:02 ` Linux does not care for data integrity (was: Disk write cache) Greg Stark
2005-05-29 21:16 ` Matthias Andree
2005-05-30 6:04 ` Greg Stark
2005-05-30 8:21 ` Matthias Andree
2005-06-01 19:02 ` Linux does not care for data integrity Bill Davidsen
2005-06-01 22:02 ` Matthias Andree
2005-06-02 0:12 ` Bill Davidsen
2005-06-02 0:36 ` Jeff Garzik
2005-06-02 1:37 ` Bill Davidsen
2005-06-02 1:54 ` Jeff Garzik
2005-06-02 8:53 ` Helge Hafting
2005-06-02 12:00 ` Bill Davidsen
2005-06-02 13:33 ` Lennart Sorensen
2005-06-04 13:37 ` Bill Davidsen
2005-06-04 15:31 ` Bernd Eckenfels
2005-05-16 14:57 ` Linux does not care for data integrity (was: Disk write cache) Alan Cox
2005-05-16 13:48 ` Linux does not care for data integrity Mark Lord
2005-05-16 14:59 ` Matthias Andree
2005-05-16 1:56 ` Disk write cache (Was: Hyper-Threading Vulnerability) Gene Heskett
2005-05-16 2:11 ` Jeff Garzik
2005-05-16 2:24 ` Mikulas Patocka
2005-05-16 3:05 ` Gene Heskett
2005-05-16 2:32 ` Mark Lord
2005-05-16 3:08 ` Gene Heskett
2005-05-16 13:44 ` Mark Lord
2005-05-18 4:03 ` Eric D. Mudama
2005-05-15 16:24 ` Mikulas Patocka
2005-05-16 11:18 ` Matthias Andree
2005-05-16 14:33 ` Jeff Garzik
2005-05-16 15:26 ` Richard B. Johnson
2005-05-16 16:00 ` [OT] drive behavior on power-off (was: Disk write cache) Matthias Andree
2005-05-16 18:11 ` Disk write cache (Was: Hyper-Threading Vulnerability) Valdis.Kletnieks
2005-05-16 14:54 ` Alan Cox
2005-05-17 13:15 ` Bill Davidsen
2005-05-17 21:41 ` Kyle Moffett
2005-05-18 4:06 ` Eric D. Mudama
2005-05-15 21:38 ` Tomasz Torcz
2005-05-16 14:50 ` Alan Cox
2005-05-15 15:00 ` Hyper-Threading Vulnerability Arjan van de Ven
2005-05-13 22:51 linux
2005-05-14 8:03 ` Arjan van de Ven
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