[8u] RFR (XS) 8231398: Add time tracing for gc log rotation at safepoint cleanup

[Andrew John Hughes]

On 01/10/2019 11:16, Aleksey Shipilev wrote:
> Thanks Paul.
> 
> I'll wait for 8u approval now.
> 
> -Aleksey
> 
> On 9/25/19 7:35 PM, Hohensee, Paul wrote:
>> Looks good.
>>
>> Paul
>>
>> On 9/24/19, 1:17 AM, "hotspot-runtime-dev on behalf of Aleksey Shipilev" <hotspot-runtime-dev-bounces at openjdk.java.net on behalf of shade at redhat.com> wrote:
>>
>>     RFE:
>>       https://bugs.openjdk.java.net/browse/JDK-8231398
>>     
>>     There is a nice gotcha when dealing with low latency workloads. The safepoint cleanup does lots of
>>     things, notably rotating the GC logs in 8 (fixed by transition to Unified Logging in 9+, see
>>     JDK-8145092). Those things are normally caught by -XX:+TraceSafepointCleanupTime, but not gc log
>>     rotation, since it misses the tracing statement.
>>     
>>     We should consider adding the tracing there.
>>     
>>     Webrev:
>>       https://cr.openjdk.java.net/~shade/8231398/webrev.01/
>>     
>>     Testing: eyeballing safepoint cleanup tracing, tier1 (running)
>>     
>>     -- 
>>     Thanks,
>>     -Aleksey
>>     
>>     
>>
> 
> 

I was expecting this to be more convoluted from the description, but
certainly have no problem with this one-liner :) Certainly don't want to
be backporting something like JDK-8145092.

Looks good and approved.

Thanks,
-- 
Andrew :)

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

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