Re: powerpc: Remove static branch prediction in atomic{, 64}_add_unless

2016-10-04 Thread Michael Ellerman
On Mon, 2016-03-10 at 06:03:03 UTC, Anton Blanchard wrote: > From: Anton Blanchard > > I see quite a lot of static branch mispredictions on a simple > web serving workload. The issue is in __atomic_add_unless(), called > from _atomic_dec_and_lock(). There is no obvious common case, so it > is bet

Re: [PATCH] powerpc: Remove static branch prediction in atomic{, 64}_add_unless

2016-10-03 Thread Nicholas Piggin
On Mon, 3 Oct 2016 17:03:03 +1100 Anton Blanchard wrote: > From: Anton Blanchard > > I see quite a lot of static branch mispredictions on a simple > web serving workload. The issue is in __atomic_add_unless(), called > from _atomic_dec_and_lock(). There is no obvious common case, so it > is be

[PATCH] powerpc: Remove static branch prediction in atomic{, 64}_add_unless

2016-10-02 Thread Anton Blanchard
From: Anton Blanchard I see quite a lot of static branch mispredictions on a simple web serving workload. The issue is in __atomic_add_unless(), called from _atomic_dec_and_lock(). There is no obvious common case, so it is better to let the hardware predict the branch. Signed-off-by: Anton Blanc