linux-kernel - Re: [PATCH [RT] 00/14] RFC

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: <20080223000345.e6be3280.akpm@linux-foundation.org>
Date:	Sat, 23 Feb 2008 00:03:45 -0800
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Gregory Haskins <ghaskins@...ell.com>, a.p.zijlstra@...llo.nl,
	tglx@...utronix.de, rostedt@...dmis.org,
	linux-rt-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	bill.huey@...il.com, kevin@...man.org, cminyard@...sta.com,
	dsingleton@...sta.com, dwalker@...sta.com, npiggin@...e.de,
	dsaxena@...xity.net, ak@...e.de, gregkh@...e.de,
	sdietrich@...ell.com, pmorreale@...ell.com, mkohari@...ell.com
Subject: Re: [PATCH [RT] 00/14] RFC - adaptive real-time locks

On Thu, 21 Feb 2008 22:24:20 +0100 Ingo Molnar <mingo@...e.hu> wrote:

> regarding the concept: adaptive mutexes have been talked about in the 
> past, but their advantage is not at all clear, that's why we havent done 
> them. It's definitely not an unambigiously win-win concept.

When ext3 was converted from sleeping locks to spinlocks, dbench-on-numaq
throughput went up by a factor of ten.  I'd expect that what RT has done
was a truly awful change for lots of workloads on lots of machines.

Yeah, there's the dont-enable-it-if-you're-doing-that option, but that adds
the we-just-doubled-the-number-of-kernels-distros-need-to-ship problem.

Does -rt also make bit_spin_lock preemptible?  If not, I'd have thought the
change was of little benefit to ext3/jbd and it might as well go back to
spinning locks.

--
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/