From: Peter Zijlstra <peterz@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
Jamie Lokier <jamie@shareable.org>,
Roland Dreier <rdreier@cisco.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 2/5] bitops: compile time optimization for hweight_long(CONSTANT)
Date: Wed, 03 Feb 2010 16:15:57 +0100 [thread overview]
Message-ID: <1265210157.24455.646.camel@laptop> (raw)
In-Reply-To: <20100203070825.e36b3932.akpm@linux-foundation.org>
On Wed, 2010-02-03 at 07:08 -0800, Andrew Morton wrote:
> On Wed, 3 Feb 2010 21:39:51 +0800 Wu Fengguang <fengguang.wu@intel.com> wrote:
>
> > Is there an official lowest GCC version that Linux supports?
>
> Documentation/Changes says gcc-3.2.
Anyway, its not like that macro I used isn't straight forward. Not much
a builtin can do better.
The only benefit the builtin has is possibly use machine popcnt
instructions but we already deal with that in the kernel.
next prev parent reply other threads:[~2010-02-03 15:16 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-30 9:45 [PATCH 0/5] [RESEND] FMODE_NONOTIFY and FMODE_NEG_OFFSET bits Wu Fengguang
2010-01-30 9:45 ` [PATCH 1/5] fanotify: fix FMODE_NONOTIFY bit number Wu Fengguang
2010-02-01 20:44 ` Andrew Morton
2010-01-30 9:45 ` [PATCH 2/5] bitops: compile time optimization for hweight_long(CONSTANT) Wu Fengguang
2010-02-01 20:48 ` Andrew Morton
2010-02-03 13:39 ` Wu Fengguang
2010-02-03 15:08 ` Andrew Morton
2010-02-03 15:15 ` Peter Zijlstra [this message]
2010-02-03 15:42 ` Andrew Morton
2010-02-03 15:47 ` Peter Zijlstra
2010-02-03 17:11 ` H. Peter Anvin
2010-02-03 18:14 ` Borislav Petkov
2010-02-03 18:47 ` Peter Zijlstra
2010-02-03 19:49 ` H. Peter Anvin
2010-02-04 15:10 ` Borislav Petkov
2010-02-04 15:13 ` Peter Zijlstra
2010-02-04 15:54 ` Borislav Petkov
2010-02-04 16:04 ` Peter Zijlstra
2010-02-05 12:11 ` Borislav Petkov
2010-02-05 12:14 ` Peter Zijlstra
2010-02-05 21:54 ` H. Peter Anvin
2010-02-06 9:36 ` Borislav Petkov
2010-02-07 1:55 ` H. Peter Anvin
2010-02-08 9:28 ` Borislav Petkov
2010-02-08 9:35 ` H. Peter Anvin
2010-02-08 9:59 ` Borislav Petkov
2010-02-11 17:24 ` Borislav Petkov
2010-02-11 17:33 ` H. Peter Anvin
2010-02-12 17:06 ` Borislav Petkov
2010-02-12 17:28 ` H. Peter Anvin
2010-02-12 17:47 ` Borislav Petkov
2010-02-12 19:05 ` H. Peter Anvin
2010-02-17 13:57 ` Michal Marek
2010-02-17 17:20 ` Borislav Petkov
2010-02-17 17:31 ` Michal Marek
2010-02-17 17:34 ` Borislav Petkov
2010-02-17 17:39 ` Michal Marek
2010-02-18 6:19 ` Borislav Petkov
2010-02-19 14:22 ` [PATCH] x86: Add optimized popcnt variants Borislav Petkov
2010-02-19 16:06 ` H. Peter Anvin
2010-02-19 16:45 ` Borislav Petkov
2010-02-19 16:53 ` H. Peter Anvin
2010-02-22 14:17 ` Borislav Petkov
2010-02-22 17:21 ` H. Peter Anvin
2010-02-22 18:49 ` Borislav Petkov
2010-02-22 19:55 ` H. Peter Anvin
2010-02-23 6:37 ` Borislav Petkov
2010-02-23 15:58 ` Borislav Petkov
2010-02-23 17:34 ` H. Peter Anvin
2010-02-23 17:54 ` Borislav Petkov
2010-02-23 18:17 ` H. Peter Anvin
2010-02-23 19:06 ` Borislav Petkov
2010-02-26 5:27 ` H. Peter Anvin
2010-02-26 7:47 ` Borislav Petkov
2010-02-26 17:48 ` H. Peter Anvin
2010-02-27 8:28 ` Borislav Petkov
2010-02-27 20:00 ` H. Peter Anvin
2010-03-09 15:36 ` Borislav Petkov
2010-03-09 15:50 ` Peter Zijlstra
2010-03-09 16:23 ` Borislav Petkov
2010-03-09 16:32 ` Peter Zijlstra
2010-03-09 17:32 ` Borislav Petkov
2010-03-09 17:37 ` Peter Zijlstra
2010-03-18 11:17 ` Borislav Petkov
2010-03-18 11:19 ` [PATCH 1/2] bitops: Optimize hweight() by making use of compile-time evaluation Borislav Petkov
2010-03-18 11:20 ` [PATCH 2/2] x86: Add optimized popcnt variants Borislav Petkov
2010-04-06 23:04 ` [tip:core/hweight] " tip-bot for Borislav Petkov
2010-04-07 7:02 ` Borislav Petkov
2010-02-18 10:51 ` [PATCH 2/5] bitops: compile time optimization for hweight_long(CONSTANT) Peter Zijlstra
2010-02-18 11:51 ` Borislav Petkov
2010-02-14 10:12 ` Peter Zijlstra
2010-02-14 11:24 ` Borislav Petkov
2010-02-14 12:23 ` Peter Zijlstra
2010-02-14 14:19 ` Borislav Petkov
2010-02-14 18:36 ` H. Peter Anvin
2010-02-14 20:28 ` Borislav Petkov
2010-02-14 22:13 ` H. Peter Anvin
2010-02-04 15:16 ` H. Peter Anvin
2010-02-04 15:39 ` Brian Gerst
2010-02-03 17:10 ` H. Peter Anvin
2010-01-30 9:45 ` [PATCH 3/5] vfs: O_* bit numbers uniqueness check Wu Fengguang
2010-01-30 9:45 ` [PATCH 4/5] vfs: introduce FMODE_NEG_OFFSET for allowing negative f_pos Wu Fengguang
2010-01-30 9:45 ` [PATCH 5/5] devmem: dont allow seek to last page Wu Fengguang
-- strict thread matches above, loose matches on Subject: below --
2010-01-22 15:50 [PATCH 00/10] perf/x86 queue Peter Zijlstra
2010-01-22 15:50 ` [PATCH 01/10] perf_events: improve x86 event scheduling (v5) Peter Zijlstra
2010-01-22 15:50 ` [PATCH 02/10] perf_events: Add fast-path to the rescheduling code Peter Zijlstra
2010-01-22 15:50 ` [PATCH 03/10] perf_event: x86: Allocate the fake_cpuc Peter Zijlstra
2010-01-29 9:27 ` [tip:perf/core] " tip-bot for Peter Zijlstra
2010-01-22 15:50 ` [PATCH 04/10] perf_event: x86: Fixup weight tying issue Peter Zijlstra
2010-01-29 9:27 ` [tip:perf/core] perf_event: x86: Fixup constraints typing issue tip-bot for Peter Zijlstra
2010-01-22 15:50 ` [PATCH 05/10] perf_event: x86: Clean up some of the u64/long bitmask casting Peter Zijlstra
2010-01-29 9:27 ` [tip:perf/core] " tip-bot for Peter Zijlstra
2010-01-22 15:50 ` [PATCH 06/10] perf_event: x86: Reduce some overly long lines with some MACROs Peter Zijlstra
2010-01-29 9:27 ` [tip:perf/core] " tip-bot for Peter Zijlstra
2010-01-22 15:50 ` [PATCH 07/10] bitops: Provide compile time HWEIGHT{8,16,32,64} Peter Zijlstra
2010-01-29 9:28 ` [tip:perf/core] " tip-bot for Peter Zijlstra
2010-01-29 10:01 ` Andrew Morton
2010-01-29 10:04 ` Ingo Molnar
2010-01-29 10:13 ` Andrew Morton
2010-01-29 11:03 ` Peter Zijlstra
2010-01-29 16:24 ` Linus Torvalds
2010-01-29 22:50 ` H. Peter Anvin
2010-01-30 16:28 ` Peter Zijlstra
2010-02-01 12:43 ` Peter Zijlstra
2010-02-01 19:06 ` H. Peter Anvin
2010-04-06 23:03 ` [tip:core/hweight] bitops: Optimize hweight() by making use of compile-time evaluation tip-bot for Peter Zijlstra
2010-01-29 10:32 ` [PATCH 07/10] bitops: Provide compile time HWEIGHT{8,16,32,64} John Kacur
2010-01-29 11:05 ` Peter Zijlstra
2010-01-29 11:13 ` John Kacur
2010-01-30 0:09 ` H. Peter Anvin
2010-01-30 7:34 ` Ingo Molnar
2010-01-22 15:50 ` [PATCH 08/10] perf_event: Optimize the constraint searching bits Peter Zijlstra
2010-01-22 16:08 ` Stephane Eranian
2010-01-22 16:22 ` Peter Zijlstra
2010-01-22 16:28 ` Stephane Eranian
2010-01-29 9:28 ` [tip:perf/core] perf_event: x86: " tip-bot for Peter Zijlstra
2010-01-22 15:50 ` [PATCH 09/10] perf_event: x86: Optimize constraint weight computation Peter Zijlstra
2010-01-29 9:28 ` [tip:perf/core] " tip-bot for Peter Zijlstra
2010-01-22 15:50 ` [PATCH 10/10] perf_event: Optimize the fast path a little more Peter Zijlstra
2010-01-29 9:28 ` [tip:perf/core] perf_event: x86: " tip-bot for Peter Zijlstra
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