On Mon, Sep 26, 2011 at 10:01 AM, Mulyadi Santosa <mulyadi.sant...@gmail.com> wrote: > Hi... > > On Mon, Sep 26, 2011 at 14:46, Jan Kiszka <jan.kis...@siemens.com> wrote: >> This increases the overhead of frequently executed helpers. >> >> Signed-off-by: Jan Kiszka <jan.kis...@siemens.com> > > IMHO, stack protector setup put more stuffs during epilogue, but quite > likely it is negligible unless it cause too much L1 cache misses. So, > I think this micro tuning is somewhat unnecessary but still okay.
The impact of stack protection is very high for instance running FFmpeg ARM with NEON optimizations: a few months ago I measured that removing stack protection improved the run time by more than 10%. Of course it's extreme since the proportion of NEON instructions (and hence of helper calls) is very high. Laurent
