I see they're using spin locks in Conversant Disruptor: < https://github.com/conversant/disruptor/blob/master/src/main/java/com/conversantmedia/util/concurrent/AbstractSpinningCondition.java>. I'd imagine something similar is in JCTools and LMAX, so it would be useful to request support for this upstream.
>From what I can tell, LinkedTransferQueue in JDK9 doesn't rely on spin locks as it's using an interesting algorithm whose documentation is literally half the source file. I see that they've updated it to use VarHandles instead of Unsafe, though, so there's that, too. On 18 December 2016 at 06:43, Remko Popma <remko.po...@gmail.com> wrote: > > > > Sent from my iPhone > On 18 Dec 2016, at 13:05, Remko Popma <remko.po...@gmail.com> wrote: > > I don't think we use spin locks in production code anywhere. > > The latency test has a wait strategy interface and one of the > implementations is spinning. I need to check the comments but not sure if I > used that strategy for the latency tests for the garbage free performance > page. > > > I just noticed that Gil Tene authored JEP 285. He is also the author of > the Pacer class used in our latency test (https://github.com/apache/ > logging-log4j2/blob/master/log4j-core/src/test/java/org/ > apache/logging/log4j/core/async/perftest/ResponseTimeTest.java) > > Our test checks the number of cores, and if sufficient, it uses the > NoOpIdleStrategy > (spin wait). The alternative is yielding the thread, but who knows when the > thread gets scheduled again (and on which core - a different core means the > cache is cold). For latency measurements of short duration, the hope is > that a spinning wait introduces less noise. > > > > Sent from my iPhone > > On 18 Dec 2016, at 10:10, Matt Sicker <boa...@gmail.com> wrote: > > I thought we were using it in AppenderControlArraySet for example, but it > doesn't look like it really matches the idea. I've been reading through all > the JEPs in JDK9 to see if there's anything else useful we haven't already > marked in our epic <https://issues.apache.org/jira/browse/LOG4J2-1564>, > and I found Thread.onSpinWait() <http://openjdk.java.net/jeps/285> which > looked useful, but I'm not sure of anywhere we could use it. > > -- > Matt Sicker <boa...@gmail.com> > > -- Matt Sicker <boa...@gmail.com>
