Messages in this thread | | | Date | Fri, 18 Apr 2014 10:33:42 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v9 06/19] qspinlock: prolong the stay in the pending bit path |
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On Thu, Apr 17, 2014 at 09:46:04PM -0400, Waiman Long wrote: > BTW, I didn't test out your atomic_test_and_set() change. Did it provide a > noticeable performance benefit when compared with cmpxchg()?
I've not tested that I think. I had a hard time showing that cmpxchg loops were slower, but once I did, I simply replaced all cmpxchg loops with unconditional ops where possible.
The machine that was big enough to show it lived in a lab half way around the world and using it was a right pain in the ass, so I didn't use it more than I absolutely had to.
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