Date: Thu, 20 Apr 2006 00:47:54 +0200 From: Carl Johan Gustavsson <carl.gustavsson@bahnhofbredband.se> To: kurt@intricatesoftware.com Cc: freebsd-java@freebsd.org Subject: Re: Diablo 1.5 SIGBUS - fixed Message-ID: <4446BE1A.6070101@bahnhofbredband.se> In-Reply-To: <200604101315.12391.lists@intricatesoftware.com> References: <C05FF5D0.246B%odela01@ca.com> <200604101315.12391.lists@intricatesoftware.com>
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Kurt Miller wrote: > The SIGBUS occurred in a thread related optimization for > multiprocessor systems that Sun introduced after the initial > release of 1.5.0. From what I can gather from a brief > inspection of the code is that they were removing unnecessary > memory barriers, but added the UseMembar option to have a > way to enable them again. The SIGBUS was happening in the > new optimized code path that didn't use a membar. > > The best description I've found so far on the use of > membar is in this old bug report: > > http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4629468 > > The following excerpt was the most relevant, "For MP systems, > a membar may still be required so that the load or store is seen > in the order desired across a machine's memory system. It depends > on the memory system." > > In other bug reports I see that on Windows for the 1.5.0_0x > releases -XX:+UseMembar is the default because of problems with > the changes. So diablo on multiprocessor systems will need to use > -XX:+UseMembar until the next release where it can be made the > default. > > -Kurt > _______________________________________________ > freebsd-java@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-java > To unsubscribe, send any mail to "freebsd-java-unsubscribe@freebsd.org" > How can I make this option default? I'm using 6.1-PRE. Thanks Carl Johan Gustavsson
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