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From: Richard Henderson <rth@twiddle.net>
To: "Emilio G. Cota" <cota@braap.org>
Cc: "QEMU Developers" <qemu-devel@nongnu.org>,
	"MTTCG Devel" <mttcg@greensocs.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Peter Crosthwaite" <crosthwaite.peter@gmail.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Sergey Fedorov" <serge.fdrv@gmail.com>
Subject: Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock
Date: Wed, 20 Apr 2016 10:55:45 -0700	[thread overview]
Message-ID: <5717C2A1.9010805@twiddle.net> (raw)
In-Reply-To: <20160420171734.GA1124@flamenco>

On 04/20/2016 10:17 AM, Emilio G. Cota wrote:
> I've tried to find a GCC intrinsic for test-and-set, and I've only found
> lock_test_and_set, which is what we use for atomic_xchg (except on ppc)
> because it really is an atomic exchange:
>   "This builtin, as described by Intel, is not a traditional test-and-set
>    operation, but rather an atomic exchange operation."
>   https://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Atomic-Builtins.html

Please read the entire documentation, not just the first sentence.


r~

  reply	other threads:[~2016-04-20 17:55 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-19 23:07 [Qemu-devel] [PATCH v3 00/11] tb hash improvements Emilio G. Cota
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 01/11] compiler.h: add QEMU_ALIGNED() to enforce struct alignment Emilio G. Cota
2016-04-22  9:32   ` Alex Bennée
2016-04-22  9:35   ` Peter Maydell
2016-04-22 15:50     ` Emilio G. Cota
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 02/11] seqlock: remove optional mutex Emilio G. Cota
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 03/11] seqlock: rename write_lock/unlock to write_begin/end Emilio G. Cota
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 04/11] include/processor.h: define cpu_relax() Emilio G. Cota
2016-04-20 12:15   ` KONRAD Frederic
2016-04-20 17:16     ` Emilio G. Cota
2016-04-20 17:18       ` Peter Maydell
2016-04-20 17:32   ` [Qemu-devel] [UPDATED " Emilio G. Cota
2016-04-22  9:35   ` [Qemu-devel] [PATCH " Alex Bennée
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock Emilio G. Cota
2016-04-20 15:18   ` Richard Henderson
2016-04-20 17:17     ` Emilio G. Cota
2016-04-20 17:55       ` Richard Henderson [this message]
2016-04-20 18:11         ` Emilio G. Cota
2016-04-20 19:39           ` Richard Henderson
2016-04-21 16:24             ` Emilio G. Cota
2016-04-20 17:35   ` [Qemu-devel] [UPDATED " Emilio G. Cota
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 06/11] exec: add tb_hash_func5, derived from xxhash Emilio G. Cota
2016-04-20 15:19   ` Richard Henderson
2016-04-22 12:58   ` Alex Bennée
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 07/11] tb hash: hash phys_pc, pc, and flags with xxhash Emilio G. Cota
2016-04-22 12:58   ` Alex Bennée
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 08/11] qht: QEMU's fast, resizable and scalable Hash Table Emilio G. Cota
2016-04-22 14:04   ` Alex Bennée
2016-04-24 20:01   ` Richard Henderson
2016-04-24 21:58     ` Emilio G. Cota
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 09/11] qht: add test program Emilio G. Cota
2016-04-22 14:35   ` Alex Bennée
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 10/11] tb hash: track translated blocks with qht Emilio G. Cota
2016-04-28 13:27   ` Alex Bennée
2016-04-19 23:07 ` [Qemu-devel] [PATCH v3 11/11] translate-all: add tb hash bucket info to 'info jit' dump Emilio G. Cota
2016-04-20 15:21   ` Richard Henderson
2016-04-22 14:38   ` Alex Bennée
2016-04-22 17:41   ` Richard Henderson
2016-04-22 19:23     ` Emilio G. Cota
2016-04-22 19:59     ` Richard Henderson
2016-04-22 23:57       ` Emilio G. Cota
2016-04-24 19:46         ` Richard Henderson
2016-04-24 22:06           ` Emilio G. Cota
2016-04-27  2:43             ` Emilio G. Cota
2016-04-28 16:37               ` Richard Henderson

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