Reduced performance in Java 9.0.1 (vs 8u152)

Laurent Bourgès bourges.laurent at
Fri Jan 5 08:59:18 UTC 2018


I wonder if the gcc compiler 4.9 used for jdk9 builds may cause some
slowdowns (native code).

I already tested few gcc options (auto vectorization) and it had some
effect on the awt library (c maskfill loops). I also tried gcc 6...

Do you experience slowdowns on linux only or is it more general (cross
platform) ?

My 2 cents...


Le 5 janv. 2018 9:37 AM, "Dawid Weiss" <dawid.weiss at> a écrit :

> Could be, but we don't use Unsafe (at least not explicitly) and the
> slowdown
> does seem to be present in various bits of software (see [1], for example),
> so it seems like something more systematic than a single method call.
> Could be a butterfly effect or a combination of different factors like
> it was already mentioned.
> Interesting nonetheless.
> Dawid
> [1] LUCENE-7966; the discussion thread contains execution times and
> discussion concerning 9 vs. 8 performance (and nobody seemed to know
> how to explain the numbers).
> focusedCommentId=16174500&page=com.atlassian.jira.
> plugin.system.issuetabpanels:comment-tabpanel#comment-16174500
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