From: "H. Peter Anvin" <hpa@zytor.com>
To: Keir Fraser <keir@xensource.com>
Cc: Andrew Morton <akpm@osdl.org>, Andi Kleen <andi@firstfloor.org>,
Chris Wright <chrisw@sous-sol.org>,
David Rientjes <rientjes@google.com>,
Virtualization Mailing List <virtualization@lists.osdl.org>,
Hugh Dickins <hugh@veritas.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/4] i386 - pte update optimizations
Date: Fri, 13 Apr 2007 08:34:06 -0700 [thread overview]
Message-ID: <461FA2EE.5090103@zytor.com> (raw)
In-Reply-To: <C2452891.D417%keir@xensource.com>
Keir Fraser wrote:
> On 13/4/07 13:27, "Andi Kleen" <andi@firstfloor.org> wrote:
>
>>> LOCKed instruction suck really badly on the netburst microarchitecture (like
>>> factor of 10x, or not far off). I think it's probably because of their side
>>> effect of serialising memory accesses, causing horrible pipeline stalls.
>> Unfortunately they tend to be HyperThreaded usually (except for early ones
>> and Celerons) and need the LOCK anyways.
>
> Fair point, although quite a few people disable HT.
Note we're talking a UP-only hack.
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Keir Fraser <keir@xensource.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Zachary Amsden <zach@vmware.com>, Andrew Morton <akpm@osdl.org>,
Virtualization Mailing List <virtualization@lists.osdl.org>,
Chris Wright <chrisw@sous-sol.org>,
David Rientjes <rientjes@google.com>,
Hugh Dickins <hugh@veritas.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/4] i386 - pte update optimizations
Date: Fri, 13 Apr 2007 08:34:06 -0700 [thread overview]
Message-ID: <461FA2EE.5090103@zytor.com> (raw)
In-Reply-To: <C2452891.D417%keir@xensource.com>
Keir Fraser wrote:
> On 13/4/07 13:27, "Andi Kleen" <andi@firstfloor.org> wrote:
>
>>> LOCKed instruction suck really badly on the netburst microarchitecture (like
>>> factor of 10x, or not far off). I think it's probably because of their side
>>> effect of serialising memory accesses, causing horrible pipeline stalls.
>> Unfortunately they tend to be HyperThreaded usually (except for early ones
>> and Celerons) and need the LOCK anyways.
>
> Fair point, although quite a few people disable HT.
Note we're talking a UP-only hack.
-hpa
next prev parent reply other threads:[~2007-04-13 15:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-12 5:30 [PATCH 0/4] i386 - pte update optimizations Zachary Amsden
2007-04-13 1:25 ` H. Peter Anvin
2007-04-13 1:25 ` H. Peter Anvin
2007-04-13 2:24 ` Zachary Amsden
2007-04-13 6:00 ` Eric Dumazet
2007-04-13 6:25 ` H. Peter Anvin
2007-04-13 9:31 ` Keir Fraser
2007-04-13 12:27 ` Andi Kleen
2007-04-13 11:31 ` Keir Fraser
2007-04-13 15:34 ` H. Peter Anvin [this message]
2007-04-13 15:34 ` H. Peter Anvin
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