From: linux@horizon.com
To: linux-kernel@vger.kernel.org
Cc: rostedt@goodmis.org
Subject: Re: [PATCH] speed up on find_first_bit for i386 (let compiler do the work)
Date: 29 Jul 2005 10:37:26 -0400 [thread overview]
Message-ID: <20050729143726.24317.qmail@science.horizon.com> (raw)
> OK, I guess when I get some time, I'll start testing all the i386 bitop
> functions, comparing the asm with the gcc versions. Now could someone
> explain to me what's wrong with testing hot cache code. Can one
> instruction retrieve from memory better than others?
To add one to Linus' list, note that all current AMD & Intel chips
record instruction boundaries in L1 cache, either predecoding on
L1 cache load, or marking the boundaries on first execution.
The P4 takes it to an extreme, but P3 and K7/K8 do it too.
The result is that there are additional instruction decode limits
that apply to cold-cache code.
next reply other threads:[~2005-07-29 14:37 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-29 14:37 linux [this message]
2005-07-29 15:08 ` linux-os (Dick Johnson)
-- strict thread matches above, loose matches on Subject: below --
2005-08-01 2:00 linux
2005-07-31 16:33 Richard Kennedy
2005-07-27 14:13 [RFC][PATCH] Make MAX_RT_PRIO and MAX_USER_RT_PRIO configurable Steven Rostedt
2005-07-28 1:00 ` Daniel Walker
2005-07-28 1:25 ` Steven Rostedt
2005-07-28 3:06 ` Steven Rostedt
2005-07-28 3:32 ` Steven Rostedt
2005-07-28 3:45 ` Steven Rostedt
2005-07-28 3:51 ` Nick Piggin
2005-07-28 11:43 ` [PATCH] speed up on find_first_bit for i386 (let compiler do the work) Steven Rostedt
2005-07-28 12:45 ` Steven Rostedt
2005-07-28 15:31 ` Linus Torvalds
2005-07-28 15:30 ` Linus Torvalds
2005-07-28 15:47 ` Steven Rostedt
2005-07-28 16:34 ` Maciej W. Rozycki
2005-07-28 16:57 ` Steven Rostedt
2005-07-28 17:25 ` Linus Torvalds
2005-07-29 10:03 ` David Woodhouse
2005-07-29 14:41 ` Maciej W. Rozycki
2005-07-29 16:23 ` Linus Torvalds
2005-07-29 14:39 ` Maciej W. Rozycki
2005-07-29 16:29 ` Linus Torvalds
2005-07-29 17:14 ` Maciej W. Rozycki
2005-07-28 17:17 ` Linus Torvalds
2005-07-29 15:09 ` Maciej W. Rozycki
2005-07-28 18:25 ` Steven Rostedt
2005-07-28 18:56 ` Linus Torvalds
2005-07-28 17:52 ` Mitchell Blank Jr
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