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Mathieu Desnoyers wrote: > I tried it with and without the LOCK prefix on my Pentium 4. > > Locked cmpxchg8b : 90 cycles > Non locked cmpxchg8b: 30 cycles > sti: 166 cycles > cli: 159 cycles > > So, hrm, even if we use the locked version, it is still much faster than > the sti/cli. I am thoughtful about the comment in asm-i386/system.h: Curious: what does it look like if the memory is not in cache? I found that cmpxchg is relatively slower than other rmw instructions in that case. -- SUSE Labs, Novell Inc. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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