Messages in this thread | | | From | Petr Tesarik <> | Subject | Re: Serious problem with ticket spinlocks on ia64 | Date | Sat, 28 Aug 2010 00:13:18 +0200 |
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On Friday 27 of August 2010 23:11:55 Luck, Tony wrote: > > One more idea. The wrap-around case is the only one when the high word is > > modified. This is in fact the only case when the fetchadd.acq competes > > with the st2.rel about the actual contents of that location. I don't know > > if it matters... > > I pondered that for a while - but I have difficulty believing that > fetchadd looks at which bits changed and only writes back the bytes > that did.
OTOH the counter is only 15-bit, so it also wraps around at 0xfffe7fff, but I have never seen it fail there. It always fails after the wrap-around from 0xfffeffff.
Petr Tesarik
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