Turn on SMS by default on ARM

Revital Eres revital.eres at linaro.org
Tue Aug 23 11:20:32 UTC 2011


Hello,

Following today performance call
(https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2011-08-23)
here are some points raised regarding the steps towards enabling SMS by default:

* Benchmarks testing:

-- Running benchmarks as EEMBC and SPEC2006 with SMS enabled is
crucial to expose loops where SMS degrades the performance. those
loops need to be analysed to construct a cost model.
-- SMS increases code size by introducing prologue and epilogue to the
loop kernel. This should also be measured.
-- Measure increase in compile time: on native or cross build?

Currently SMS fails to bootstrap trunk on ARM machine. this should
also be taken into account when considering enabling it by default.

Should it be turned on with -O2 or -O3?

SMS flags to use for testing:

-O3 -fmodulo-sched-allow-regmoves -fmodulo-sched
-funsafe-loop-optimizations  -fno-auto-inc-dec

Thanks,
Revital



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