On Mon, 3 Jul 2006, Robert Watson wrote:
On Mon, 3 Jul 2006, David Xu wrote:
I found 5% performance decrease on dual P4, maybe P4 is quite bad when
doing atomic operation. ;-) Thanks,
When I've measured, generally, yes, P4 performance has been abysmal for
synchronization operations, both atomic operations and CPU-local interrupt
disabling, etc.
I suspect rwlocks could use a bit of optimization in the contention case.
I've not dug into the code, so I'm not clear how they compare with respect
to adaptive behavior.
I ran some micro-benchmarks, and rwlocks don't perform substantially
differently from sleep mutexes for uncontended operation -- I've not measured
cost under contention, however.
Robert N M Watson
Computer Laboratory
University of Cambridge
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