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https://issues.apache.org/jira/browse/LUCENE-2504?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12909407#action_12909407
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Yonik Seeley commented on LUCENE-2504:
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bq. The open question is whether this hotspot fickleness is particular to
Oracle's java impl, or, is somehow endemic to bytecode VMs (.NET included).
I tried IBM's latest Java6 (SR8 FP1, 20100624)
It seems to have some of the same pitfalls as Oracle's JVM, just different.
The first run does not differ from the second run in the same JVM as it does
with Oracle, but the first run itself has much more variation. The worst case
is worse, and just like the Oracle JVM, it gets stuck in it's worst case.
Each run (of the complete set of fields) in a separate JVM since two runs in
the same JVM didn't really differ as they did in the oracle JVM.
branch_3x:
|unique terms in field|median sort time of 100 sorts in ms|another run|another
run|another run|another run|another run|another run
|100000|129|128|130|109|98|128|135
|10000|128|123|127|127|98|128|135
|1000|129|130|130|128|98|130|136
|100|128|133|133|130|100|132|139
|10|150|153|153|154|122|153|159
trunk:
|unique terms in field|median sort time of 100 sorts in ms|another run|another
run|another run|another run|another run|another run
|100000|217|81|383|99|79|78|215
|10000|254|73|346|101|106|108|267
|1000|253|74|347|99|107|108|258
|100|253|107|394|98|107|102|255
|10|251|107|388|99|106|98|257
The second way of testing is to completely mix fields (no serial correlation
between what field is sorted on). This is the test that is very predictable
with the Oracle JVM, but I still see wide variability with the IBM JVM. Here
is the list of different runs for the Oracle JVM (ms):
branch_3x
|128|129|123|120|128|100|95|74|130|91|120
trunk
|106|89|168|116|155|119|108|118|112|169|165
To my eye, it looks like we have more variability in trunk, due to increased
use of abstractions?
> sorting performance regression
> ------------------------------
>
> Key: LUCENE-2504
> URL: https://issues.apache.org/jira/browse/LUCENE-2504
> Project: Lucene - Java
> Issue Type: Bug
> Affects Versions: 4.0
> Reporter: Yonik Seeley
> Fix For: 4.0
>
> Attachments: LUCENE-2504.patch, LUCENE-2504.patch, LUCENE-2504.patch,
> LUCENE-2504.zip
>
>
> sorting can be much slower on trunk than branch_3x
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