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From: Avi Kivity <avi@qumranet.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	Steven Rostedt <rostedt@goodmis.org>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
	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>
Subject: Re: Efficient x86 and x86_64 NOP microbenchmarks
Date: Wed, 13 Aug 2008 21:45:35 +0300	[thread overview]
Message-ID: <48A32BCF.40300@qumranet.com> (raw)
In-Reply-To: <20080813184142.GM1366@one.firstfloor.org>

Andi Kleen wrote:
> So for me the best strategy would be to get rid of the frame pointer
> and ignore the nops. This unfortunately would require going away
> from -pg and instead post process gcc output to insert "call mcount"
> manually. But the nice advantage of that is that you could actually 
> set up a custom table of callers built in a ELF section and with
> that you don't actually need the runtime patching (which is only
> done currently because there's no global table of mcount calls),
> but could do everything in stop_machine(). Without
> runtime patching you also don't need single part nops. 
>
> I think that would be the best option. I especially like it because
> it would prevent forcing frame pointer which seems to be costlier
> than any kinds of nosp.
>
>   

How would you deal with inlines?  Using debug information?

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.


  reply	other threads:[~2008-08-13 18:45 UTC|newest]

Thread overview: 106+ 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 [this message]
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
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
     [not found] <20080813191926.GB15547@Krystal>
2008-08-13 20:00 ` Efficient x86 and x86_64 NOP microbenchmarks Steven Rostedt
2008-08-13 20:06   ` Jeremy Fitzhardinge
2008-08-13 20:34     ` Steven Rostedt
2008-08-13 20:15   ` Andi Kleen
2008-08-13 20:21     ` Linus Torvalds
2008-08-13 20:21     ` Steven Rostedt

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