From: tip-bot for Linus Torvalds <torvalds@linux-foundation.org>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com,
torvalds@linux-foundation.org, tglx@linutronix.de, mingo@elte.hu
Subject: [tip:x86/urgent] x86: Optimize cmpxchg64() at build-time some more
Date: Thu, 1 Oct 2009 06:40:17 GMT [thread overview]
Message-ID: <tip-982d007a6eec4a0abb404d2355eeec2c041c61ea@git.kernel.org> (raw)
In-Reply-To: <alpine.LFD.2.01.0909301743150.6996@localhost.localdomain>
Commit-ID: 982d007a6eec4a0abb404d2355eeec2c041c61ea
Gitweb: http://git.kernel.org/tip/982d007a6eec4a0abb404d2355eeec2c041c61ea
Author: Linus Torvalds <torvalds@linux-foundation.org>
AuthorDate: Wed, 30 Sep 2009 17:57:27 -0700
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 1 Oct 2009 08:01:08 +0200
x86: Optimize cmpxchg64() at build-time some more
Try to avoid the 'alternates()' code when we can statically
determine that cmpxchg8b is fine. We already have that
CONFIG_x86_CMPXCHG64 (enabled by PAE support), and we could easily
also enable it for some of the CPU cases.
Note, this patch only adds CMPXCHG8B for the obvious Intel CPU's,
not for others. (There was something really messy about cmpxchg8b
and clone CPU's, so if you enable it on other CPUs later, do it
carefully.)
If we avoid that asm-alternative thing when we can assume the
instruction exists, we'll generate less support crud, and we'll
avoid the whole issue with that extra 'nop' for padding instruction
sizes etc.
LKML-Reference: <alpine.LFD.2.01.0909301743150.6996@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/Kconfig.cpu | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 527519b..f2824fb 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -400,7 +400,7 @@ config X86_TSC
config X86_CMPXCHG64
def_bool y
- depends on X86_PAE || X86_64
+ depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM
# this should be set for all -march=.. options where the compiler
# generates cmov.
@@ -412,6 +412,7 @@ config X86_MINIMUM_CPU_FAMILY
int
default "64" if X86_64
default "6" if X86_32 && X86_P6_NOP
+ default "5" if X86_32 && X86_CMPXCHG64
default "4" if X86_32 && (X86_XADD || X86_CMPXCHG || X86_BSWAP || X86_WP_WORKS_OK)
default "3"
next prev parent reply other threads:[~2009-10-01 6:41 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-27 22:34 Linux 2.6.32-rc1 Linus Torvalds
2009-09-27 23:44 ` Stephen Rothwell
2009-09-27 23:48 ` Diego Calleja
2009-09-27 23:52 ` Linus Torvalds
2009-09-28 0:17 ` Stephen Rothwell
2009-09-28 7:07 ` Eric Dumazet
2009-09-28 15:39 ` Linus Torvalds
2009-09-28 17:15 ` Martin Schwidefsky
2009-09-28 18:41 ` Eric Dumazet
2009-09-28 20:56 ` Martin Schwidefsky
2009-09-29 20:42 ` Eric Dumazet
2009-09-29 21:17 ` Linus Torvalds
2009-09-29 21:22 ` Arjan van de Ven
2009-09-29 21:56 ` Linus Torvalds
2009-09-30 15:07 ` Arjan van de Ven
2009-09-30 15:27 ` Eric Dumazet
2009-09-30 15:31 ` Arjan van de Ven
2009-10-01 0:42 ` Yuhong Bao
2009-09-30 15:57 ` Eric Dumazet
2009-09-30 16:13 ` Arjan van de Ven
2009-09-30 16:14 ` Linus Torvalds
2009-09-30 18:53 ` Ingo Molnar
2009-09-30 22:03 ` [GIT PULL] scheduler fixes Ingo Molnar
2009-10-01 0:42 ` Linus Torvalds
2009-10-01 0:57 ` Linus Torvalds
2009-10-01 5:30 ` Eric Dumazet
2009-10-01 6:11 ` Ingo Molnar
2009-10-01 6:18 ` Eric Dumazet
2009-10-01 6:42 ` Ingo Molnar
2009-10-01 6:59 ` Eric Dumazet
2009-10-01 7:28 ` Sam Ravnborg
2009-10-01 6:49 ` [tip:x86/urgent] x86: Don't generate cmpxchg8b_emu if CONFIG_X86_CMPXCHG64=y tip-bot for Eric Dumazet
2009-10-01 6:40 ` tip-bot for Linus Torvalds [this message]
2009-10-02 16:40 ` [GIT PULL] scheduler fixes Yuhong Bao
2009-10-01 6:05 ` Ingo Molnar
2009-09-30 16:14 ` Linux 2.6.32-rc1 Cyrill Gorcunov
2009-09-30 16:55 ` Stefan Richter
2009-09-30 17:08 ` Linus Torvalds
2009-09-30 17:40 ` Stefan Richter
2009-09-30 19:32 ` Ingo Molnar
2009-09-30 19:35 ` Ingo Molnar
2009-09-30 20:16 ` Eric Dumazet
2009-09-30 20:20 ` Linus Torvalds
2009-09-30 20:22 ` Ingo Molnar
2009-09-30 20:38 ` Ingo Molnar
2009-10-01 7:18 ` Arjan van de Ven
2009-09-30 19:37 ` [tip:sched/urgent] x86: Provide an alternative() based cmpxchg64() tip-bot for Arjan van de Ven
2009-09-30 19:37 ` [tip:sched/urgent] sched_clock: Fix atomicity/continuity bug by using cmpxchg64() tip-bot for Arjan van de Ven
2009-09-30 19:39 ` Ingo Molnar
2009-09-30 19:39 ` tip-bot for Eric Dumazet
2009-09-30 20:19 ` Linux 2.6.32-rc1 Linus Torvalds
2009-09-30 20:24 ` Eric Dumazet
2009-09-30 20:41 ` Linus Torvalds
2009-09-30 20:49 ` Ingo Molnar
2009-09-30 20:53 ` Eric Dumazet
2009-09-30 21:00 ` Ingo Molnar
2009-09-30 20:54 ` Linus Torvalds
2009-09-30 21:53 ` David Miller
2009-10-01 12:48 ` Christoph Hellwig
2009-10-01 16:08 ` Valdis.Kletnieks
2009-10-05 14:39 ` Peter Zijlstra
2009-09-30 20:40 ` [tip:sched/urgent] x86: Provide an alternative() based cmpxchg64() tip-bot for Arjan van de Ven
2009-09-30 20:58 ` Ingo Molnar
2009-09-30 20:40 ` [tip:sched/urgent] sched_clock: Fix atomicity/continuity bug by using cmpxchg64() tip-bot for Eric Dumazet
2009-09-30 20:55 ` [tip:sched/urgent] x86: Provide an alternative() based cmpxchg64() tip-bot for Arjan van de Ven
2009-09-30 20:55 ` [tip:sched/urgent] sched_clock: Fix atomicity/continuity bug by using cmpxchg64() tip-bot for Eric Dumazet
2009-09-30 21:00 ` [tip:sched/urgent] x86: Provide an alternative() based cmpxchg64() tip-bot for Arjan van de Ven
2009-09-30 21:01 ` [tip:sched/urgent] sched_clock: Fix atomicity/continuity bug by using cmpxchg64() tip-bot for Eric Dumazet
2009-10-05 16:00 ` [PATCH] x86: Generate cmpxchg build failures Peter Zijlstra
2009-10-05 18:51 ` Maciej Żenczykowski
2009-10-05 19:16 ` Linus Torvalds
2009-10-05 19:33 ` Peter Zijlstra
2009-10-05 20:54 ` Linus Torvalds
2009-10-09 14:23 ` [tip:x86/asm] " tip-bot for Peter Zijlstra
2009-09-28 14:34 ` Linux 2.6.32-rc1 compile error Wolfgang Erig
2009-09-28 15:10 ` Jaswinder Singh Rajput
2009-09-28 15:32 ` Wolfgang Erig
2009-09-28 16:25 ` [PATCH] isdn: fix netjet/isdnhdlc build errors Randy Dunlap
2009-09-28 19:47 ` David Miller
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