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https://issues.apache.org/jira/browse/YARN-1297?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13860792#comment-13860792
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Karthik Kambatla commented on YARN-1297:
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First round of comments:
# Would be nice to see what the gains are corresponding to replacing
ResourcePBImpl with SimpleResource. If it is not noticeable, it might be better
to leave it as is.
# At a couple of places, instead of modifying the resource usage of a queue
this way, it would be better to add a method to FSQueue that does this.
{code}
+ Resources.addTo(cur.getResourceUsage(), container.getResource());
{code}
# I am surprised direct comparisons instead of DefaultResourceCalculator have a
noticeable performance difference. Can we measure the gains due to this change,
and drop it if none.
{code}
- Resource minShare1 = Resources.min(RESOURCE_CALCULATOR, null,
- s1.getMinShare(), s1.getDemand());
+ int minShare1 = Math.min(s1.getMinShare().getMemory(),
+ s1.getDemand().getMemory());
{code}
# I am not an expert, but I hear Math#signum is supposed to be optimized for
performance. Just curious - how much did changing this help?
> Miscellaneous Fair Scheduler speedups
> -------------------------------------
>
> Key: YARN-1297
> URL: https://issues.apache.org/jira/browse/YARN-1297
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: scheduler
> Reporter: Sandy Ryza
> Assignee: Sandy Ryza
> Attachments: YARN-1297-1.patch, YARN-1297.patch, YARN-1297.patch
>
>
> I ran the Fair Scheduler's core scheduling loop through a profiler to and
> identified a bunch of minimally invasive changes that can shave off a few
> milliseconds.
> The main one is demoting a couple INFO log messages to DEBUG, which brought
> my benchmark down from 16000 ms to 6000.
> A few others (which had way less of an impact) were
> * Most of the time in comparisons was being spent in Math.signum. I switched
> this to direct ifs and elses and it halved the percent of time spent in
> comparisons.
> * I removed some unnecessary instantiations of Resource objects
> * I made it so that queues' usage wasn't calculated from the applications up
> each time getResourceUsage was called.
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