linux-kernel - Re: [PATCH] i386-pda UP optimization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 15 Nov 2006 10:24:21 -0800
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Arjan van de Ven <arjan@...radead.org>
CC:	Ingo Molnar <mingo@...e.hu>, Andi Kleen <ak@...e.de>,
	Eric Dumazet <dada1@...mosbay.com>, akpm@...l.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] i386-pda UP optimization

Arjan van de Ven wrote:
> segment register accesses really are not cheap. 
> Also really it'll be better to use the register userspace is not using,
> but we had that discussion before; could you remind me why you picked 
> %gs in the first place?
>   

To leave open the possibility of using the compiler's TLS support in the
kernel for percpu.  I also measured the cost of reloading %gs vs %fs,
and found no difference between reloading a null selector vs a non-null
selector.

    J

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/