From: "H. Peter Anvin" <hpa@zytor.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Nick Piggin <npiggin@kernel.dk>,
Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH RFC 0/7] x86: convert ticketlocks to C and remove duplicate code
Date: Wed, 22 Jun 2011 13:19:39 -0700 [thread overview]
Message-ID: <4E024E5B.7090103@zytor.com> (raw)
In-Reply-To: <4E0240AC.9060603@goop.org>
On 06/22/2011 12:21 PM, Jeremy Fitzhardinge wrote:
>
> A friend just pointed out that gcc has a "__sync_fetch_and_add()"
> intrinsic, which compiles to xadd when used in this context. What's the
> general feeling about using these kinds of gcc features?
>
In general they are good, IF:
a) they cover all versions of gcc we care about (or we have a fallback),
and
b) they have the right semantics.
Using gcc intrinsics can generate better code than we can in inline
assembly.
However, (b) is a killer since gcc doesn't have a way to generate our
lock prefix annotations, and so it isn't really useful here.
-hpa
next prev parent reply other threads:[~2011-06-22 20:20 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-16 21:40 [PATCH RFC 0/7] x86: convert ticketlocks to C and remove duplicate code Jeremy Fitzhardinge
2011-06-16 21:40 ` [PATCH 1/7] x86/ticketlock: clean up types and accessors Jeremy Fitzhardinge
2011-06-16 21:40 ` [PATCH 2/7] x86/ticketlock: convert spin loop to C Jeremy Fitzhardinge
2011-06-16 21:40 ` [PATCH 3/7] x86/ticketlock: Use C for __ticket_spin_unlock Jeremy Fitzhardinge
2011-06-16 21:40 ` [PATCH 4/7] x86/ticketlock: make large and small ticket versions of spin_lock the same Jeremy Fitzhardinge
2011-06-16 21:40 ` [PATCH 5/7] x86/ticketlock: make __ticket_spin_lock common Jeremy Fitzhardinge
2011-06-16 21:40 ` [PATCH 6/7] x86/ticketlock: make __ticket_spin_trylock common Jeremy Fitzhardinge
2011-06-16 21:40 ` [PATCH 7/7] x86/ticketlock: prevent memory accesses from reordered out of lock region Jeremy Fitzhardinge
2011-06-21 14:01 ` [PATCH RFC 0/7] x86: convert ticketlocks to C and remove duplicate code Peter Zijlstra
2011-06-21 17:54 ` Jeremy Fitzhardinge
2011-06-22 19:21 ` Jeremy Fitzhardinge
2011-06-22 20:19 ` H. Peter Anvin [this message]
2011-06-22 20:59 ` Jeremy Fitzhardinge
2011-06-22 21:07 ` H. Peter Anvin
2011-06-22 21:35 ` Jeremy Fitzhardinge
2011-06-22 23:16 ` H. Peter Anvin
2011-06-21 14:18 ` Konrad Rzeszutek Wilk
2011-06-24 1:19 ` [PATCH 1/8] x86/ticketlock: clean up types and accessors Jeremy Fitzhardinge
2011-06-24 1:19 ` [PATCH 2/8] x86/ticketlock: convert spin loop to C Jeremy Fitzhardinge
2011-07-22 19:55 ` [tip:x86/spinlocks] x86, ticketlock: Convert " tip-bot for Jeremy Fitzhardinge
2011-06-24 1:19 ` [PATCH 3/8] x86/ticketlock: Use C for __ticket_spin_unlock Jeremy Fitzhardinge
2011-06-24 21:52 ` H. Peter Anvin
2011-06-24 22:41 ` Jeremy Fitzhardinge
2011-07-22 18:32 ` H. Peter Anvin
2011-07-22 19:28 ` Jeremy Fitzhardinge
2011-07-22 19:56 ` [tip:x86/spinlocks] x86, ticketlock: Use asm volatile for __ticket_unlock_release() tip-bot for H. Peter Anvin
2011-07-22 19:56 ` [tip:x86/spinlocks] x86, ticketlock: Use C for __ticket_spin_unlock tip-bot for Jeremy Fitzhardinge
2011-06-24 1:19 ` [PATCH 4/8] x86/ticketlock: make large and small ticket versions of spin_lock the same Jeremy Fitzhardinge
2011-07-22 19:57 ` [tip:x86/spinlocks] x86, ticketlock: Make " tip-bot for Jeremy Fitzhardinge
2011-06-24 1:19 ` [PATCH 5/8] x86/ticketlock: make __ticket_spin_lock common Jeremy Fitzhardinge
2011-07-22 19:57 ` [tip:x86/spinlocks] x86, ticketlock: Make " tip-bot for Jeremy Fitzhardinge
2011-06-24 1:19 ` [PATCH 6/8] x86/ticketlock: make __ticket_spin_trylock common Jeremy Fitzhardinge
2011-07-22 19:57 ` [tip:x86/spinlocks] x86, ticketlock: Make " tip-bot for Jeremy Fitzhardinge
2011-06-24 1:19 ` [PATCH 7/8] x86: add xadd helper macro Jeremy Fitzhardinge
2011-07-22 19:58 ` [tip:x86/spinlocks] x86: Add " tip-bot for Jeremy Fitzhardinge
2011-06-24 1:19 ` [PATCH 8/8] x86/ticketlock: use xadd helper Jeremy Fitzhardinge
2011-07-22 19:58 ` [tip:x86/spinlocks] x86, ticketlock: Use " tip-bot for Jeremy Fitzhardinge
2011-07-22 19:55 ` [tip:x86/spinlocks] x86, ticketlock: Clean up types and accessors tip-bot for Jeremy Fitzhardinge
2011-06-24 21:50 ` [PATCH RFC 0/7] x86: convert ticketlocks to C and remove duplicate code H. Peter Anvin
2011-06-24 22:42 ` Jeremy Fitzhardinge
2011-06-25 3:15 ` H. Peter Anvin
2011-07-15 17:24 ` Jeremy Fitzhardinge
2011-07-15 23:06 ` H. Peter Anvin
2011-07-16 0:14 ` Jeremy Fitzhardinge
2011-06-25 10:11 ` Ingo Molnar
2011-06-29 20:44 ` Andi Kleen
2011-07-21 23:33 ` Jeremy Fitzhardinge
2011-07-22 16:25 ` Andi Kleen
2011-09-07 23:25 ` Jeremy Fitzhardinge
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