[8u] RFR: 8227006: [linux] Runtime.availableProcessors execution time increased by factor of 100

[Andrew Hughes]

On 17:04 Mon 16 Nov     , Severin Gehwolf wrote:
> Hi Jon,
> 
> On Tue, 2020-11-10 at 13:51 +0000, Jonathan Dowland wrote:
> > Original bug: https://bugs.openjdk.java.net/browse/JDK-8227006
> > Original rev: https://hg.openjdk.java.net/jdk/jdk/rev/c440a6b4e096
> > 
> > RFR webrev: https://cr.openjdk.java.net/~shade/8227006/webrev.8u.01/
> 
> This backport looks good to me. I can sponsor the push for you and add
> the label/comment.
> 
> > Please review this backport for jdk8u-dev for parity with Oracle JDK 8u281.
> > 
> > The original patch did not apply cleanly to jdk8u-dev. I had to untangle
> > it from related changes from JDK-8232207.
> 
> Right. JDK-8232207 doesn't affect OpenJDK 8u so we shouldn't backport
> it. Dropping changes to CgroupMemorySubsystem is the right call.
> 
> >  I also re-worked a call to
> > "log_trace" to use "tty->print_cr" conditionally on (PrintContainerInfo)
> > set, matching other uses in the file.
> 
> OK.
> 
> > One can see the cache in operation by executing the following and
> > comparing the output before/after:
> > 
> >     java -XX:+UnlockDiagnosticVMOptions -XX:PrintContainerInfo -version
> 
> I've also run the reproducer from the bug.
> 
> Before:
> -------
> $ java Test
> 72448 calls/sec
> 71024 calls/sec
> 61751 calls/sec
> 59997 calls/sec
> 68613 calls/sec
> 70358 calls/sec
> 
> After:
> -------
> $ java Test
> 25218164 calls/sec
> 26279378 calls/sec
> 26165449 calls/sec
> 24962446 calls/sec
> 24157175 calls/sec
> 24020916 calls/sec
> 25469665 calls/sec
> 
> Thanks,
> Severin
> 

Looks good to me too. Approved.

Thanks,
-- 
Andrew :)

Senior Free Java Software Engineer
OpenJDK Package Owner
Red Hat, Inc. (http://www.redhat.com)

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