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  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:	Tue, 18 Feb 2014 14:30:12 -0500
From:	Waiman Long <>
To:	Peter Zijlstra <>
CC:	"H. Peter Anvin" <>,
	Thomas Gleixner <>,
	Ingo Molnar <>, Arnd Bergmann <>,,,, Steven Rostedt <>,
	Andrew Morton <>,
	Michel Lespinasse <>,
	Andi Kleen <>,
	Rik van Riel <>,
	"Paul E. McKenney" <>,
	Linus Torvalds <>,
	Raghavendra K T <>,
	George Spelvin <>,
	Tim Chen <>,
	Daniel J Blueman <>,
	Alexander Fyodorov <>,
	Aswin Chandramouleeswaran <>,
	Scott J Norton <>,
	Thavatchai Makphaibulchoke <>
Subject: Re: [PATCH v4 0/3] qspinlock: Introducing a 4-byte queue spinlock

On 02/18/2014 02:31 AM, Peter Zijlstra wrote:
> 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.

I will start looking at how to make it work with paravirt. Hopefully, it 
won't take too long.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists