From: "H. Peter Anvin" <hpa@zytor.com>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Andi Kleen <andi@firstfloor.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
Steven Rostedt <srostedt@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Miller <davem@davemloft.net>,
Roland McGrath <roland@redhat.com>,
Ulrich Drepper <drepper@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
Gregory Haskins <ghaskins@novell.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
"Luis Claudio R. Goncalves" <lclaudio@uudg.org>,
Clark Williams <williams@redhat.com>,
Christoph Lameter <cl@linux-foundation.org>
Subject: Re: [RFC PATCH] x86 alternatives : fix LOCK_PREFIX race with preemptible kernel and CPU hotplug
Date: Thu, 14 Aug 2008 10:17:11 -0700 [thread overview]
Message-ID: <48A46897.4040900@zytor.com> (raw)
In-Reply-To: <20080814165802.GC517@Krystal>
Mathieu Desnoyers wrote:
>
> Sure, here are the updated tables. Basically, they show no significant
> difference between the NOP and the DS segment selector prefix
> approaches.
>
Actually, unless I have blown my T-test completely, they show with a 80%
and 74% confidence (respective for the two benchmarks) that the DS case
is slightly *better* (0.26% and 0.20% better, respective), which makes
it a no-brainer. Doing around 10 runs of each is likely to confirm this
conclusion by pushing it into the 90+% interval.
Note that since the difference is so small, and so can also be due to
some kind of systematic error (lower ambient temperature during the DS
run making the disk drive slightly faster, what have you.)
-hpa
next prev parent reply other threads:[~2008-08-14 17:24 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-07 18:20 [PATCH 0/5] ftrace: to kill a daemon Steven Rostedt
2008-08-07 18:20 ` [PATCH 1/5] ftrace: create __mcount_loc section Steven Rostedt
2008-08-07 18:20 ` [PATCH 2/5] ftrace: mcount call site on boot nops core Steven Rostedt
2008-08-07 18:20 ` [PATCH 3/5] ftrace: enable mcount recording for modules Steven Rostedt
2008-08-08 6:43 ` Rusty Russell
2008-08-08 12:51 ` Steven Rostedt
2008-08-07 18:20 ` [PATCH 4/5] ftrace: rebuild everything on change to FTRACE_MCOUNT_RECORD Steven Rostedt
2008-08-07 18:20 ` [PATCH 5/5] ftrace: enable using mcount recording on x86 Steven Rostedt
2008-08-07 18:47 ` [PATCH 0/5] ftrace: to kill a daemon Mathieu Desnoyers
2008-08-07 20:42 ` Steven Rostedt
2008-08-08 17:22 ` Mathieu Desnoyers
2008-08-08 17:36 ` Steven Rostedt
2008-08-08 17:46 ` Mathieu Desnoyers
2008-08-08 18:13 ` Steven Rostedt
2008-08-08 18:15 ` Peter Zijlstra
2008-08-08 18:21 ` Mathieu Desnoyers
2008-08-08 18:41 ` Steven Rostedt
2008-08-08 19:04 ` Linus Torvalds
2008-08-08 19:05 ` Mathieu Desnoyers
2008-08-08 23:38 ` Steven Rostedt
2008-08-09 0:23 ` Andi Kleen
2008-08-09 0:36 ` Steven Rostedt
2008-08-09 0:47 ` Jeremy Fitzhardinge
2008-08-09 0:51 ` Linus Torvalds
2008-08-09 1:25 ` Steven Rostedt
2008-08-13 6:31 ` Mathieu Desnoyers
2008-08-13 15:38 ` Mathieu Desnoyers
2008-08-13 17:52 ` Efficient x86 and x86_64 NOP microbenchmarks Mathieu Desnoyers
2008-08-13 18:27 ` Linus Torvalds
2008-08-13 18:41 ` Andi Kleen
2008-08-13 18:45 ` Avi Kivity
2008-08-13 18:51 ` Andi Kleen
2008-08-13 18:56 ` Avi Kivity
2008-08-13 19:30 ` Mathieu Desnoyers
2008-08-13 19:37 ` Andi Kleen
2008-08-13 20:01 ` Mathieu Desnoyers
2008-08-13 23:41 ` [RFC PATCH] x86 alternatives : fix LOCK_PREFIX race with preemptible kernel and CPU hotplug Mathieu Desnoyers
2008-08-14 0:01 ` H. Peter Anvin
2008-08-14 1:13 ` Mathieu Desnoyers
2008-08-14 1:22 ` Jeremy Fitzhardinge
2008-08-14 1:26 ` Roland McGrath
2008-08-14 1:49 ` Mathieu Desnoyers
2008-08-14 3:35 ` Jeremy Fitzhardinge
2008-08-14 15:18 ` Mathieu Desnoyers
2008-08-14 16:10 ` Linus Torvalds
2008-08-14 16:13 ` H. Peter Anvin
2008-08-14 16:58 ` Mathieu Desnoyers
2008-08-14 17:05 ` Jeremy Fitzhardinge
2008-08-14 17:30 ` Mathieu Desnoyers
2008-08-14 17:43 ` Jeremy Fitzhardinge
2008-08-14 18:37 ` H. Peter Anvin
2008-08-14 18:53 ` Mathieu Desnoyers
2008-08-14 19:29 ` Jeremy Fitzhardinge
2008-08-14 20:31 ` Mathieu Desnoyers
2008-08-14 20:39 ` H. Peter Anvin
2008-08-14 21:46 ` Jeremy Fitzhardinge
2008-08-14 22:26 ` H. Peter Anvin
2008-08-14 17:17 ` H. Peter Anvin [this message]
2008-08-14 18:09 ` Mathieu Desnoyers
2008-08-14 19:49 ` Mathieu Desnoyers
2008-08-14 17:04 ` Jeremy Fitzhardinge
2008-08-14 17:18 ` H. Peter Anvin
2008-08-14 17:28 ` Jeremy Fitzhardinge
2008-08-14 17:31 ` H. Peter Anvin
2008-08-14 17:46 ` Mathieu Desnoyers
2008-08-14 17:49 ` Jeremy Fitzhardinge
2008-08-14 17:55 ` Mathieu Desnoyers
2008-08-14 18:59 ` Gregory Haskins
2008-08-15 21:34 ` Efficient x86 and x86_64 NOP microbenchmarks Steven Rostedt
2008-08-15 21:51 ` Andi Kleen
2008-08-13 19:16 ` Mathieu Desnoyers
2008-08-09 0:51 ` [PATCH 0/5] ftrace: to kill a daemon Steven Rostedt
2008-08-09 0:53 ` Roland McGrath
2008-08-09 1:13 ` Andi Kleen
2008-08-09 1:19 ` Andi Kleen
2008-08-09 1:30 ` Steven Rostedt
2008-08-09 1:55 ` Andi Kleen
2008-08-09 2:03 ` Steven Rostedt
2008-08-09 2:23 ` Andi Kleen
2008-08-09 4:12 ` Steven Rostedt
2008-08-09 0:30 ` Steven Rostedt
2008-08-11 18:21 ` Mathieu Desnoyers
2008-08-11 19:28 ` Steven Rostedt
2008-08-08 19:08 ` Jeremy Fitzhardinge
2008-08-11 2:41 ` Rusty Russell
2008-08-11 12:33 ` Steven Rostedt
2008-08-07 21:11 ` Jeremy Fitzhardinge
2008-08-07 21:29 ` Steven Rostedt
2008-08-07 22:26 ` Roland McGrath
2008-08-08 1:21 ` Steven Rostedt
2008-08-08 1:24 ` Steven Rostedt
2008-08-08 1:56 ` Steven Rostedt
2008-08-08 7:22 ` Peter Zijlstra
2008-08-08 11:31 ` Steven Rostedt
2008-08-08 4:54 ` Sam Ravnborg
2008-08-09 9:48 ` Abhishek Sagar
2008-08-09 13:01 ` Steven Rostedt
2008-08-09 15:01 ` Abhishek Sagar
2008-08-09 15:37 ` Steven Rostedt
2008-08-09 17:14 ` Abhishek Sagar
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