On Sun, 2008-10-12 at 07:46 +0200, Nick Piggin wrote: > Speed up generic mutex implementations. > > - atomic operations which both modify the variable and return something imply > full smp memory barriers before and after the memory operations involved > (failing atomic_cmpxchg, atomic_add_unless, etc don't imply a barrier > because > they don't modify the target). See Documentation/atomic_ops.txt. > So remove extra barriers and branches. > > - All architectures support atomic_cmpxchg. This has no relation to > __HAVE_ARCH_CMPXCHG. We can just take the atomic_cmpxchg path > unconditionally > > This reduces a simple single threaded fastpath lock+unlock test from 590 > cycles > to 203 cycles on a ppc970 system. > > Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>
Looks ok. Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
