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Re: [PATCH] alternative hirate for builtin_expert

On 10/02/13 23:49, Rong Xu wrote:
Here is the new patch. Honaz: Could you take a look?



On Wed, Oct 2, 2013 at 2:31 PM, Jan Hubicka <> wrote:
Thanks for the suggestion. This is much cleaner than to use binary parameter.

Just want to make sure I understand it correctly about the orginal hitrate:
you want to retire the hitrate in PRED_BUILTIN_EXPECT and always use
the one specified in the biniltin-expect-probability parameter.


Should I use 90% as the default? It's hard to fit current value 0.9996
in percent form.

Yes, 90% seems fine.  The original value was set quite arbitrarily and no real
performance study was made as far as I know except yours. I think users that
are sure they use expect to gueard completely cold edges may just use 100%
instead of 0.9996, so I would not worry much about the precision.



OK with that change.


This broke arm-linux-gnueabihf building libstdc++-v3. I haven't dug further yet but still reducing the testcase.


for details.

Can you please deal with this appropriately ?


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