A FileChannel is guaranteed to be thread safe. You can obtain a FileChannel from a FlieOutputStream, so that would seem to imply that FileOutputStream might be thread-safe, but you can’t really know that without looking at the source. The problem is that FileChannel.write() takes a ByteBuffer whereas FileOutputStream.write() accepts a byte array. To be thread safe it would have to safely copy the byte array into the byte buffer to pass to the FileChannel. But FileOutputStream doesn’t use the FileChannel at all in Java 7. It calls a native method that doesn’t specify whether it is thread-safe or not, so simply removing the synchronization isn’t guaranteed to work properly.
OTOH, RandomAccessFile doesn’t say that it is thread-safe either and we are not synchronizing writes to it. Ralph > On Feb 7, 2017, at 8:37 AM, Matt Sicker <boa...@gmail.com> wrote: > > I looked at 1.2-SNAPSHOT and 1.1.10 and saw nothing special other than a lack > of a synchronized keyword on the equivalent append method. Perhaps he figured > out a simpler way to emulate locking? > > I've been working with async/non-blocking streaming APIs for long enough now > that I can't even remember the last time I had to write an actual lock. > > On 6 February 2017 at 22:02, Apache <ralph.go...@dslextreme.com > <mailto:ralph.go...@dslextreme.com>> wrote: > Logback 1.2-SNAPSHOT > > Ralph > >> On Feb 6, 2017, at 8:29 PM, Remko Popma <remko.po...@gmail.com >> <mailto:remko.po...@gmail.com>> wrote: >> >> Sorry what 1.2 do you mean? >> >> Sent from my iPhone >> >> On Feb 7, 2017, at 11:06, Apache <ralph.go...@dslextreme.com >> <mailto:ralph.go...@dslextreme.com>> wrote: >> >>> In 1.2? That may work for a FileOutputStream but it isn’t guaranteed to >>> work for others. >>> >>> Ralph >>> >>>> On Feb 6, 2017, at 5:23 PM, Matt Sicker <boa...@gmail.com >>>> <mailto:boa...@gmail.com>> wrote: >>>> >>>> I'm not sure if I'm looking in the right place, but a major difference now >>>> between Logback's appenders and Log4j's is that Logback isn't synchronized >>>> on the append method. >>>> >>>> On 6 February 2017 at 18:18, Matt Sicker <boa...@gmail.com >>>> <mailto:boa...@gmail.com>> wrote: >>>> Is this something we can improve performance on by implementing a file >>>> appender based on FileChannel or AsynchronousFileChannel instead of >>>> OutputStream? >>>> >>>> On 6 February 2017 at 17:50, Apache <ralph.go...@dslextreme.com >>>> <mailto:ralph.go...@dslextreme.com>> wrote: >>>> Ceki has updated his numbers to include those reported on the mailing >>>> list. >>>> https://docs.google.com/spreadsheets/d/1cpb5D7qnyye4W0RTlHUnXedYK98catNZytYIu5D91m0/edit#gid=0 >>>> >>>> <https://docs.google.com/spreadsheets/d/1cpb5D7qnyye4W0RTlHUnXedYK98catNZytYIu5D91m0/edit#gid=0> >>>> >>>> I haven’t run the tests with Logback 1.2-SNAPSHOT but my numbers for my >>>> two MacBooks are at >>>> https://docs.google.com/spreadsheets/d/1L67IhmUVvyLBWtC6iq0TMj-j0vrbKsUKWuZV0Nlqisk/edit?usp=sharing >>>> >>>> <https://docs.google.com/spreadsheets/d/1L67IhmUVvyLBWtC6iq0TMj-j0vrbKsUKWuZV0Nlqisk/edit?usp=sharing>. >>>> >>>> >>>> Ralph >>>> >>>>> On Feb 6, 2017, at 9:33 AM, Apache <ralph.go...@dslextreme.com >>>>> <mailto:ralph.go...@dslextreme.com>> wrote: >>>>> >>>>> Yes, that is still the standard approach most people use and is the only >>>>> way to provide a head-to-head comparison against the logging frameworks. >>>>> >>>>> Ralph >>>>> >>>>>> On Feb 6, 2017, at 8:02 AM, Matt Sicker <boa...@gmail.com >>>>>> <mailto:boa...@gmail.com>> wrote: >>>>>> >>>>>> This is all in a synchronous appender, right? Either way, that's rather >>>>>> interesting. >>>>>> >>>>>> On 6 February 2017 at 07:54, Apache <ralph.go...@dslextreme.com >>>>>> <mailto:ralph.go...@dslextreme.com>> wrote: >>>>>> Someone posted numbers on the Logback user’s list that match mine. It >>>>>> shows Logback 1.1.9 was pretty terrible, 1.1.10 is somewhat better and >>>>>> 1.2-SNAPSHOT is on par or slightly better than Log4j 2. >>>>>> >>>>>> Ralph >>>>>> >>>>>>> On Feb 5, 2017, at 3:25 PM, Matt Sicker <boa...@gmail.com >>>>>>> <mailto:boa...@gmail.com>> wrote: >>>>>>> >>>>>>> I think we need some comparisons on the log4j side: file appender with >>>>>>> 256k buffer size, random access file appender with 256k buffer size >>>>>>> (which appears to be the default), and memory mapped file appender. >>>>>>> It'd be cool to see how these compose with async logging enabled in >>>>>>> both log4j and logback. >>>>>>> >>>>>>> On 5 February 2017 at 16:06, Apache <ralph.go...@dslextreme.com >>>>>>> <mailto:ralph.go...@dslextreme.com>> wrote: >>>>>>> You should run the code at https://github.com/ceki/logback-perf >>>>>>> <https://github.com/ceki/logback-perf> to compare your results to >>>>>>> Ceki’s. You also should capture the cpubenchmark speed of your >>>>>>> processor and get the speed of your hard drive. I used Blackmagic speed >>>>>>> test on my Mac. I am capturing my results in a Google spreadsheet. I >>>>>>> will post the like once I have it. >>>>>>> >>>>>>> Ralph >>>>>>> >>>>>>>> On Feb 5, 2017, at 1:48 PM, Gary Gregory <garydgreg...@gmail.com >>>>>>>> <mailto:garydgreg...@gmail.com>> wrote: >>>>>>>> >>>>>>>> If you want, I can run tests on Windows once the build works on >>>>>>>> Windows again. >>>>>>>> >>>>>>>> Let me know what args/command line... >>>>>>>> >>>>>>>> Gary >>>>>>>> >>>>>>>> On Feb 5, 2017 11:58 AM, "Apache" <ralph.go...@dslextreme.com >>>>>>>> <mailto:ralph.go...@dslextreme.com>> wrote: >>>>>>>> I guess my MacBook Pro must fit in the Slow CPU/Fast Hard drive >>>>>>>> category. With Logback 1.10 and -t 4 now get >>>>>>>> >>>>>>>> Benchmark Mode Samples >>>>>>>> Score Error Units >>>>>>>> o.a.l.l.p.j.FileAppenderBenchmark.julFile thrpt 20 >>>>>>>> 98187.673 ± 4935.712 ops/s >>>>>>>> o.a.l.l.p.j.FileAppenderBenchmark.log4j1File thrpt 20 >>>>>>>> 842374.496 ± 6762.712 ops/s >>>>>>>> o.a.l.l.p.j.FileAppenderBenchmark.log4j2File thrpt 20 >>>>>>>> 1853062.583 ± 67032.225 ops/s >>>>>>>> o.a.l.l.p.j.FileAppenderBenchmark.log4j2RAF thrpt 20 >>>>>>>> 2036011.226 ± 53208.281 ops/s >>>>>>>> o.a.l.l.p.j.FileAppenderBenchmark.logbackFile thrpt 20 >>>>>>>> 999667.438 ± 12074.003 ops/s >>>>>>>> >>>>>>>> I’ll have to try this on one my VMs at work. We don’t run anything >>>>>>>> directly on bare metal any more. >>>>>>>> >>>>>>>> Ralph >>>>>>>> >>>>>>>>> On Feb 5, 2017, at 9:40 AM, Apache <ralph.go...@dslextreme.com >>>>>>>>> <mailto:ralph.go...@dslextreme.com>> wrote: >>>>>>>>> >>>>>>>>> Ceki finally fixed some of the performance problems in the >>>>>>>>> FileAppender. See https://logback.qos.ch/news.html >>>>>>>>> <https://logback.qos.ch/news.html> and >>>>>>>>> https://docs.google.com/spreadsheets/d/1cpb5D7qnyye4W0RTlHUnXedYK98catNZytYIu5D91m0/edit#gid=0 >>>>>>>>> >>>>>>>>> <https://docs.google.com/spreadsheets/d/1cpb5D7qnyye4W0RTlHUnXedYK98catNZytYIu5D91m0/edit#gid=0>. >>>>>>>>> I suspect we have a few optimizations we can make. >>>>>>>>> >>>>>>>>> Ralph >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Matt Sicker <boa...@gmail.com <mailto:boa...@gmail.com>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Matt Sicker <boa...@gmail.com <mailto:boa...@gmail.com>> >>>>> >>>> >>>> >>>> >>>> >>>> -- >>>> Matt Sicker <boa...@gmail.com <mailto:boa...@gmail.com>> >>>> >>>> >>>> >>>> -- >>>> Matt Sicker <boa...@gmail.com <mailto:boa...@gmail.com>> >>> > > > > > -- > Matt Sicker <boa...@gmail.com <mailto:boa...@gmail.com>>
