From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Steven Rostedt <rostedt@goodmis.org>,
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>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
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>,
srostedt@redhat.com
Subject: Re: [PATCH] ftrace: use only 5 byte nops for x86
Date: Fri, 15 Aug 2008 15:52:31 -0700 [thread overview]
Message-ID: <48A608AF.5050307@zytor.com> (raw)
In-Reply-To: <alpine.LFD.1.10.0808151542330.3324@nehalem.linux-foundation.org>
Linus Torvalds wrote:
>>>
>> I think what we need to do is to test the NOPL instruction and create a
>> Linux-specific CPUID bit for it. I'll do that and submit to tip:x86/cpu.
>
> I also suspect that we'd really be much better off just fixing the generic
> NOP tables for the 5-byte nop. As far as I could tell, from all the
> numbers that have been posted, absolutely _none_ show that there is any
> point at all to the 2-instruction 3/2-byte sequence.
>
> So instead of having a magic special ftrace-only thing, why not just do it
> right, and fix the generic 5-byte nop sequence?
>
There is that, too. The two are orthogonal.
-hpa
prev parent reply other threads:[~2008-08-15 23:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-14 22:05 [PATCH] ftrace: use only 5 byte nops for x86 Steven Rostedt
2008-08-14 23:49 ` Jeremy Fitzhardinge
2008-08-15 9:22 ` Ingo Molnar
2008-08-15 22:30 ` H. Peter Anvin
2008-08-15 22:44 ` Linus Torvalds
2008-08-15 22:50 ` Jeremy Fitzhardinge
2008-08-15 22:52 ` H. Peter Anvin [this message]
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