RFR: 8266723: JFR periodic events are causing extra allocations

[Andrew Dinn]

Hi Jaroslav,

The patch looks good to me so consider it reviewed.

I agree that testing on other architectures would be a good idea even 
though the code changes are clearly independent of architecture.

regards,


Andrew Dinn
-----------
Red Hat Distinguished Engineer
Red Hat UK Ltd
Registered in England and Wales under Company Registration No. 03798903
Directors: Michael Cunningham, Michael ("Mike") O'Neill

On 17/05/2021 09:27, Jaroslav Bachorík wrote:
> Gentle ping?
> 
> -JB-
> 
> On Fri, May 7, 2021 at 5:54 PM Jaroslav Bachorík
> <jaroslav.bachorik at datadoghq.com> wrote:
>>
>> Please, review the following fix.
>>
>> JIRA:  https://bugs.openjdk.java.net/browse/JDK-8266723
>> Webrev:
>>   - hotspot: http://cr.openjdk.java.net/~jbachorik/8266723/hotspot/00/webrev/
>>   - jdk: http://cr.openjdk.java.net/~jbachorik/8266723/jdk/00/webrev/
>>
>> In short, the JFR backport for JDK 8 could not bring in the whole JVM
>> logging framework and took a several shortcuts. Unfortunately, one of
>> the shortcuts is causing the log messages always generated but not
>> persisted resulting in possible disturbance in GC due to excessive
>> allocations.
>>
>> The gist of the patch is binding the java side JFR logger log level
>> check with the global 'LogJFR' flag which is already used in the
>> native JFR logger implementation.
>>
>> The path builds fine and passes tier1 and jfr tests on linux. Since
>> the changes are not platform specific I am expecting the tests passing
>> on other platforms as well.
>> If there is a volunteer able to run tests for this patch on more
>> platforms it would be welcome.
>>
>> Cheers,
>>
>> -JB-
>