Improving the performance of OpenJDK

[Gary Benson]

Gary Benson wrote:
...
> > > > Edward Nevill wrote:
> > > > > get_native_u2() and get_Java_u2() ... This seems to be a
> > > > > misguided attempt of the original authors to optimised
> > > > > reading of halfwords (judging by the comment immediate
> > > > > preceding the code).
...
> So I did a quick SPECjvm98 run of this change on amd64.  A couple of
> the times are improved, by 3-10%, but one of the times is *slower*
> by 11%.  See attached.  I'm not sure what to make of that...

I'm wondering if rewriting get_Java_u2() to read directly rather than
read and swap is speeding it up, but removing the optimization from
get_native_u2() is slowing it down.  I'm going to try this with the
original get_native_u2() and with get_Java_u2() just a copy of the
big-endian get_native_u2().

Cheers,
Gary

-- 
http://gbenson.net/