From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
the arch/x86 maintainers <x86@kernel.org>,
Davidlohr Bueso <dbueso@suse.de>,
"H. Peter Anvin" <hpa@zytor.com>,
virtualization <virtualization@lists.linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>, Andy Lutomirski <luto@kernel.org>,
Andrey Konovalov <andreyknvl@google.com>,
Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH v2 2/3] x86: drop a comment left over from X86_OOSTORE
Date: Tue, 12 Jan 2016 22:25:28 +0000 [thread overview]
Message-ID: <20160112222528.4a1d9b64@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <1452635935-5439-3-git-send-email-mst@redhat.com>
On Wed, 13 Jan 2016 00:10:19 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> The comment about wmb being non-nop is a left over from before commit
> 09df7c4c8097 ("x86: Remove CONFIG_X86_OOSTORE").
>
> It makes no sense now: if you have an SMP system with out of order
> stores, making wmb not a nop will not help.
There were never any IDT Winchip systems with SMP support, and they were
the one system that could enable OOSTORE (and it was worth up to 30% on
some workloads). The fencing it had was just for DMA devices.
Alan
next prev parent reply other threads:[~2016-01-12 22:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-12 22:10 [PATCH v2 0/3] x86: faster mb()+other barrier.h tweaks Michael S. Tsirkin
2016-01-12 22:10 ` [PATCH v2 1/3] x86: drop mfence in favor of lock+addl Michael S. Tsirkin
2016-01-12 22:10 ` [PATCH v2 2/3] x86: drop a comment left over from X86_OOSTORE Michael S. Tsirkin
2016-01-12 22:25 ` One Thousand Gnomes [this message]
2016-01-12 22:10 ` [PATCH v2 3/3] x86: tweak the comment about use of wmb for IO Michael S. Tsirkin
2016-01-12 22:25 ` [PATCH v2 0/3] x86: faster mb()+other barrier.h tweaks H. Peter Anvin
2016-01-26 8:20 ` Michael S. Tsirkin
2016-01-26 21:37 ` H. Peter Anvin
2016-01-27 14:07 ` Michael S. Tsirkin
2016-01-27 14:14 ` Peter Zijlstra
2016-01-27 14:18 ` Michael S. Tsirkin
2018-10-11 17:37 ` Andres Freund
2018-10-11 18:11 ` Michael S. Tsirkin
2018-10-11 18:21 ` Andres Freund
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