[infinispan-dev] if (trace) logger.tracef - it makes sense

[Sebastian Laskawiec]

Hey David!

It's Java Util Logging (so the JDKLogger implementation).

Thanks
Sebastian

On Fri, Sep 30, 2016 at 1:53 PM, David M. Lloyd <david.lloyd at redhat.com>
wrote:

> On 09/30/2016 01:53 AM, Sebastian Laskawiec wrote:
> > Hey!
> >
> > A while ago I asked Radim and Dan about these kind of constructs [1]:
> >
> > private boolean trace = logger.isTraceEnabled(); //stored in a field
> >
> > ... called in some method ...
> >     if(trace)
> >         logger.tracef(...);
> > ...
> >
> > At first they seemed wrong to me, because if one changes logging level
> > (using JMX for example), the code won't notice it. I also though it's
> > quite ok to use tracef directly, because JIT will inline and optimize it.
> >
> > Unfortunately my benchmarks [2] show that I was wrong. Logger#tracef
> > indeed checks if the logging level is enabled but since JBoss Logging
> > may use different backends, the check is not trivial and is not inlined
> > (at least with default settings).
>
> What backend where you using with your test?
>
> > The performance results look like this:
> > Benchmark                  Mode  Cnt           Score          Error
> Units
> > MyBenchmark.noVariable    thrpt   20   *717252060.124* ± 13420522.229
> ops/s
> > MyBenchmark.withVariable  thrpt   20  *2358360244.627* ± 50214969.572
> ops/s
> >
> > So if you even see a construct like this: logger.debuf or logger.tracef
> > - make sure you check if the logging level is enabled (and the check
> > result is stored in a field).
> >
> > That was a bit surprising and interesting lesson :D
> >
> > Thanks
> > Sebastian
> >
> > [1] https://github.com/infinispan/infinispan/pull/4538#
> discussion_r80666086
> > [2] https://github.com/slaskawi/jboss-logging-perf-test
> >
> >
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> >
>
> --
> - DML
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