Jon Masamitsu's Weblog

  • Java
    August 24, 2006

The GC whitepaper

Guest Author
There's a very nice whitepaper on our GC at


It talks about basic concepts, some specifics about our GC, suggestions on
tuning, and some of the latest improvements such as the parallel old
collector. If you've looked at the GC tuning guides, some of it will look
familiar, but it nicely pulls together information from several sources.

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Comments ( 4 )
  • Moazam Raja Thursday, August 24, 2006
    Nice, a consolidated quick guide! Funny enough, the first dozen pages look like my own 'cheatsheet notes'. :)

  • Damon Hart-Davis Friday, August 25, 2006

    Yes, a very good summary/overview, and it cleaned up some of the garbage I'd accumulated in my head about the different mechanisms.

    [Someone really should merge the names of the overlapping attributes/flags (eg to avoid the "no policy got set" problems with parallel ref collection) so that we don't need to remember 50 ways of saying the same things!]



  • Jon Mausamits Monday, August 28, 2006

    There is a bug that has to do with flag names and a bug that has to do with a missing policy in the parallel reference processing. The bugs are

    6432517 - Policy missing in GC parallel reference processing

    6362902 - Use uniform names for GC flags/parameters/names/verbose-logs across all collectors whenever possible

    Do either address the problem you've raised.

  • Damon Hart-Davis Monday, August 28, 2006
    Hi Jon,

    Yes, both are exactly what I had in mind... More simple for you to code and for simple people like me to use correctly...



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