From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>, Andi Kleen <ak@suse.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Arjan van de Ven <arjan@infradead.org>,
Zachary Amsden <zach@vmware.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Michael A Fetterman <Michael.Fetterman@cl.cam.ac.uk>
Subject: Re: Assignment of GDT entries
Date: Wed, 13 Sep 2006 15:22:25 -0700 [thread overview]
Message-ID: <450884A1.2060905@goop.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0609131454480.4388@g5.osdl.org>
Linus Torvalds wrote:
> So I'd not be surprised if movign the TLS segments around would break
> something.
>
I don't think so. 32-bit code running on x86-64 has different TLS
selectors, and everything seems to work there...
> That said, numbers talk, bullshit walks. If the above just works a lot
> better for all modern CPU's that all have 64-byte cachelines (because now
> _everything_ is in that bigger cacheline), and if you can show that with
> numbers, and nothing breaks in practice, then hey..
>
My goal would be to do a minimal change which packs all the useful stuff
together in a 64-byte line. Ideally it would just use two 32-byte
lines, but I don't think that's as important.
Caching effects are pretty hard to measure anyway, and with something as
deeply x86-microarchitectural as this, I could imagine lots of other CPU
cleverness which could obscure any simple measurement. But packing
things into a line certainly can't hurt.
I'll put something together, and see how it goes...
J
next prev parent reply other threads:[~2006-09-13 22:22 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-13 18:58 Assignment of GDT entries Jeremy Fitzhardinge
2006-09-13 19:16 ` Arjan van de Ven
2006-09-13 20:00 ` Alan Cox
2006-09-13 20:02 ` Jeremy Fitzhardinge
2006-09-13 20:20 ` Jeremy Fitzhardinge
2006-09-13 20:59 ` Zachary Amsden
2006-09-13 21:15 ` Jeremy Fitzhardinge
2006-09-13 21:35 ` Alan Cox
2006-09-14 0:25 ` Zachary Amsden
2006-09-14 1:40 ` Stephen Rothwell
2006-09-14 13:03 ` Alan Cox
2006-09-13 19:55 ` linux-os (Dick Johnson)
2006-09-13 20:08 ` Jeremy Fitzhardinge
2006-09-13 20:32 ` linux-os (Dick Johnson)
2006-09-13 21:21 ` Linus Torvalds
2006-09-13 21:47 ` Jeremy Fitzhardinge
2006-09-13 22:05 ` Linus Torvalds
2006-09-13 22:22 ` Jeremy Fitzhardinge [this message]
2006-09-14 6:00 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2006-09-14 3:23 Albert Cahalan
2006-09-14 6:11 ` Jeremy Fitzhardinge
2006-09-14 4:06 Albert Cahalan
2006-09-14 4:44 ` Eric W. Biederman
2006-09-14 6:19 ` Albert Cahalan
2006-09-14 6:28 ` Zachary Amsden
2006-09-14 7:12 ` Albert Cahalan
2006-09-14 7:24 ` Zachary Amsden
2006-09-14 6:29 ` Jeremy Fitzhardinge
2006-09-15 7:55 Mikael Pettersson
2006-09-15 8:20 ` Jeremy Fitzhardinge
2006-09-15 8:58 ` Mikael Pettersson
2006-09-15 18:27 ` Jeremy Fitzhardinge
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