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 for Android: free password hash cracker in your pocket

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

Message-ID: <53029167.4060109@zytor.com>
Date:	Mon, 17 Feb 2014 14:47:03 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Waiman Long <Waiman.Long@...com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Arnd Bergmann <arnd@...db.de>
CC:	linux-arch@...r.kernel.org, x86@...nel.org,
	linux-kernel@...r.kernel.org,
	Peter Zijlstra <peterz@...radead.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 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.

	-hpa


--
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/