Messages in this thread | | | Date | Sat, 3 Nov 2007 04:41:46 +0100 | From | Nick Piggin <> | Subject | Re: [patch 1/4] x86: FIFO ticket spinlocks |
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On Fri, Nov 02, 2007 at 08:56:46PM -0400, Chuck Ebbert wrote: > On 11/02/2007 07:01 PM, Nick Piggin wrote: > > > > In the contended multi-threaded tight loop, the xchg lock is slower than inc > > lock but still beats the fair xadd lock, but that's only because it is > > just as unfair if not more so on this hardware (runtime difference of up to > > about 10%) > > > > I meant xchg for unlock, not lock.
That is for unlock. 2x the number of atomic operations ~= 2x the cost.
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