linux-kernel - Re: [PATCH v4 0/3] qspinlock: Introducing a 4-byte queue spinlock

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: <20140218073111.GW27965@twins.programming.kicks-ass.net>
Date:	Tue, 18 Feb 2014 08:31:11 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Waiman Long <Waiman.Long@...com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Arnd Bergmann <arnd@...db.de>,
	linux-arch@...r.kernel.org, x86@...nel.org,
	linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Michel Lespinasse <walken@...gle.com>,
	Andi Kleen <andi@...stfloor.org>,
	Rik van Riel <riel@...hat.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>,
	George Spelvin <linux@...izon.com>,
	Tim Chen <tim.c.chen@...ux.intel.com>,
	Daniel J Blueman <daniel@...ascale.com>,
	Alexander Fyodorov <halcy@...dex.ru>,
	Aswin Chandramouleeswaran <aswin@...com>,
	Scott J Norton <scott.norton@...com>,
	Thavatchai Makphaibulchoke <thavatchai.makpahibulchoke@...com>
Subject: Re: [PATCH v4 0/3] qspinlock: Introducing a 4-byte queue spinlock

On Mon, Feb 17, 2014 at 02:47:03PM -0800, H. Peter Anvin wrote:
> On 02/17/2014 12:41 PM, Waiman Long wrote:
> > v3->v4:
> >  - Remove debugging code and fix a configuration error
> >  - Simplify the qspinlock structure and streamline the code to make it
> >    perform a bit better
> >  - Add an x86 version of asm/qspinlock.h for holding x86 specific
> >    optimization.
> >  - Add an optimized x86 code path for 2 contending tasks to improve
> >    low contention performance.
> > 
> > v2->v3:
> >  - Simplify the code by using numerous mode only without an unfair option.
> >  - Use the latest smp_load_acquire()/smp_store_release() barriers.
> >  - Move the queue spinlock code to kernel/locking.
> >  - Make the use of queue spinlock the default for x86-64 without user
> >    configuration.
> >  - Additional performance tuning.
> > 
> > v1->v2:
> >  - Add some more comments to document what the code does.
> >  - Add a numerous CPU mode to support >= 16K CPUs
> >  - Add a configuration option to allow lock stealing which can further
> >    improve performance in many cases.
> >  - Enable wakeup of queue head CPU at unlock time for non-numerous
> >    CPU mode.
> > 
> > This patch set introduces a queue-based spinlock implementation that
> > can replace the default ticket spinlock without increasing the size
> > of the spinlock data structure. As a result, critical kernel data
> > structures that embed spinlock won't increase in size and breaking
> > data alignments.
> > 
> 
> This is starting to look good, so I have pulled it into
> tip:x86/spinlocks to start give it some testing mileage.

It very much needs paravirt muck before we can even consider it.
--
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/