linux-kernel - Re: [rfc][patch] queued spinlocks (i386)

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]

Message-ID: <17925.18904.820106.145029@gargle.gargle.HOWL>
Date:	Sat, 24 Mar 2007 18:55:04 +0300
From:	Nikita Danilov <nikita@...sterfs.com>
To:	Nick Piggin <npiggin@...e.de>
Cc:	Ingo Molnar <mingo@...e.hu>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ravikiran G Thirumalai <kiran@...lex86.org>
Subject: Re: [rfc][patch] queued spinlocks (i386)

Nick Piggin writes:
 > On Fri, Mar 23, 2007 at 11:04:18AM +0100, Ingo Molnar wrote:
 > > 
 > > * Nick Piggin <npiggin@...e.de> wrote:
 > > 
 > > > Implement queued spinlocks for i386. [...]
 > > 
 > > isnt this patented by MS? (which might not worry you SuSE/Novell guys, 
 > > but it might be a worry for the rest of the world ;-)
 > 
 > Hmm, it looks like they have implemented a system where the spinning
 > cpu sleeps on a per-CPU variable rather than the lock itself, and
 > the releasing cpu writes to that variable to wake it.  They do this
 > so that spinners don't continually perform exclusive->shared
 > transitions on the lock cacheline. They call these things queued
 > spinlocks.  They don't seem to be very patent worthy either, but

Indeed, this technique is very well known. E.g.,
http://citeseer.ist.psu.edu/anderson01sharedmemory.html has a whole
section (3. Local-spin Algorithms) on them, citing papers from the 1990
onward.

Nikita.

-
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/