FW: RFR(S): 8215284: Reduce noise induced by periodic task getFileSize()

[Markus Gronlund]

Thanks Claes and Erik for your reviews.

Agree on your nit Claes, fixed. Thanks for noticing.

Cheers
Markus

-----Original Message-----
From: Claes Redestad 
Sent: den 13 december 2018 14:12
To: Markus Gronlund <markus.gronlund at oracle.com>; hotspot-runtime-dev at openjdk.java.net
Subject: Re: FW: RFR(S): 8215284: Reduce noise induced by periodic task getFileSize()

Looks good to me.

Nit: calling should_rotate() in on_rotation seems a bit superfluous

/Claes

On 2018-12-13 10:57, Markus Gronlund wrote:
> Hello,
> 
> I am widening this post a tad bit in the hope of getting review assistance for this particular issue.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8215284
> Webrev: http://cr.openjdk.java.net/~mgronlun/8215284/webrev01/
> 
> Thanks in advance
> Markus
> 
> -----Original Message-----
> From: Markus Gronlund
> Sent: den 12 december 2018 23:52
> To: hotspot-jfr-dev at openjdk.java.net
> Subject: RFR(S): 8215284: Reduce noise induced by periodic task getFileSize()
> 
> Greetings,
> 
> Can I get a review for the following:
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8215284
> Webrev: http://cr.openjdk.java.net/~mgronlun/8215284/webrev01/
> 
> Summary: The periodic task operation runs in Java checking the file size of the current chunk. This produces unnecessary exposure and noise by the JFR framework itself. It is especially interesting that the path to check the size of a file produces a memory allocation trace....most likely some effect of autoboxing and lambda constructions...
> 
> We can avoid this by diving into the VM instead to test for the rotateDisk condition since the amount written to the current chunk is already tracked there.
> 
> Testing: jdk_jfr
> 
> Thanks
> Markus
>