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https://issues.apache.org/jira/browse/LUCENE-9535?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17200160#comment-17200160
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Uwe Schindler edited comment on LUCENE-9535 at 9/22/20, 3:37 PM:
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Michael: Are all your CPU fans OK?
I had this problem on the Policeman Jenkins server. When the temperature goes
up, Linux slows down CPU frequency. Maybe that's happening here, because the
CPU is busy for longer time.
was (Author: thetaphi):
Michael: Are all your CPU fans OK?
I had this problem on the Policeman Jenkins server. When the temperature goes
up, Linux slows down CPU frequency. Maybe that'Äs happening here, because the
CPU is busy for longer time.
> Investigate recent indexing slowdown for wikimedium documents
> -------------------------------------------------------------
>
> Key: LUCENE-9535
> URL: https://issues.apache.org/jira/browse/LUCENE-9535
> Project: Lucene - Core
> Issue Type: Task
> Reporter: Adrien Grand
> Priority: Minor
> Attachments: cpu_profile.svg
>
>
> Nightly benchmarks report a ~10% slowdown for 1kB documents as of September
> 9th: [http://people.apache.org/~mikemccand/lucenebench/indexing.html].
> On that day, we added stored fields in DWPT accounting (LUCENE-9511), so I
> first thought this could be due to smaller flushed segments and more merging,
> but I still wonder whether there's something else. The benchmark runs with
> 8GB of heap, 2GB of RAM buffer and 36 indexing threads. So it's about 2GB/36
> = 57MB of RAM buffer per thread in the worst-case scenario that all DWPTs get
> full at the same time. Stored fields account for about 0.7MB of memory, or 1%
> of the indexing buffer size. How can a 1% reduction of buffering capacity
> explain a 10% indexing slowdown? I looked into this further by running
> indexing benchmarks locally with 8 indexing threads and 128MB of indexing
> buffer memory, which would make this issue even more apparent if the smaller
> RAM buffer was the cause, but I'm not seeing a regression and actually I'm
> seeing similar number of flushes when I disabled memory accounting for stored
> fields.
> I ran indexing under a profiler to see whether something else could cause
> this slowdown, e.g. slow implementations of ramBytesUsed on stored fields
> writers, but nothing surprising showed up and the profile looked just like I
> would have expected.
> Another question I have is why the 4kB benchmark is not affected at all.
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