Aleksey Shipilev wrote:
On 07 Nov 2007 00:27:25 +0300, Egor Pasko <[EMAIL PROTECTED]> wrote:
Vladimir, guess what? :) I actually mixed several things
altogether.
<giggly>(sigh) As usual, miracle does not happen :) I dreamed to see
software sqrt() implementation that could be faster than hardware one.
</giggly>
So, we are left with SSE asm that can be inlined by JIT and AFAI can
see it is not as fast as HotSpot? Weird :)
No, for now we have just the intrinsic in native code, so we also have
overheads for JNI transition (and it is heavy!), parameter passing,
chains of calls, etc. I believe that sqrt() magic will lead that NBody
performance very close to RI.
BTW, in my thought this benchmark is like the top of the iceberg
called "FP performance problems".
Thanks,
Aleksey.
You might be interested to know that the JikesRVM implementation calls
out to glibc via a fast syscall (we have an @SysCall annotation for
native methods), and it is 1.5x slower than Sun 1.6 on a Core2/Linux for
Tim's (non-strict) benchmark. Maybe you can squeeze the overhead of
intrinsic calls down a bit further ?
cheers
cheers
