Messages in this thread | | | Date | Tue, 18 Feb 2014 14:30:12 -0500 | From | Waiman Long <> | Subject | Re: [PATCH v4 0/3] qspinlock: Introducing a 4-byte queue spinlock |
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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.
-Longman
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