JNI-performance - Is it really that fast?

Clemens Eisserer linuxhippy at gmail.com
Wed Mar 26 22:21:01 UTC 2008


Hello,

>  The atomics proper shouldn't be any more expensive on a 256-way than
>  on a 2-way  .... Those are CPU-local effects.  Furthermore
>  they're largely an implementation artifact as until recently processor
>  designers didn't pay too much attention to atomic latency.  Thankfully
>  that appears to be changing and we're seeing more efficient atomics.
Good to know, thanks for explaining.
I don't want to steal your time, but, if its only a local thing why is
my old pentium4 so much faster than my core2duo when it comes to
cmpxchg?
Sorry for asking that much...

> If I'm interpreting the data correctly, that doesn't seem too
>  surprising.   There was a sufficiently long warmup period, and the
>  warmup exercised the code in precisely the same way it would execute
>  during the benchmark interval?
Yes, exactly.
On my Pentium4 the buffering is even faster, because JNI is really slow on it.

Thanks for your time and patience, lg Clemens



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