Messages in this thread | | | Date | Sat, 5 Oct 2002 10:14:34 +1000 | From | Anton Blanchard <> | Subject | Re: [PATCH] patch-slab-split-03-tail |
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> <<<<<<< > An object cache's CPU layer contains per-CPU state that must be > protected either by per-CPU locking or by disabling interrupts. We > selected per-CPU locking for several reasons: > [...] > x Performance. On most modern processors, grabbing an uncontended > lock is cheaper than modifying the processor interrupt level. > <<<<<<<< > > Which cpus have slow local_irq_disable() implementations? At least for > my Duron, this doesn't seem to be the case [~ 4 cpu cycles for cli]
Rusty did some tests and found on the intel chips he tested local_irq_disable was slower. He posted the results to lkml a few weeks ago.
On ppc64 it varies between chips.
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