cvs commit: src/sys/i386/i386 pmap.c
rwatson at FreeBSD.org
Tue Nov 9 21:09:16 GMT 2004
On Tue, 9 Nov 2004, Julian Elischer wrote:
> Is this with HTT?
> We've dicoverred that HTT makes better code run slower, remember?
Nope, the issue here is a minor tweak in the spin lock code that causes
moving away from an atomic operation to make it run slower rather than
faster. I think John has a theory that the lack of using an atomic
operation slows the rate at which the change is visible on other
processors by virtue of being non-atomic, so locks contend longer.
Robert N M Watson FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org Principal Research Scientist, McAfee Research
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