From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: iozone reality check: was zam, please discuss this Date: Wed, 23 Jun 2004 22:13:04 -0700 Message-ID: <40DA62E0.2050803@namesys.com> References: <40D8EB0D.6050109@namesys.com> <20040623063049.GA5080@backtop.namesys.com> <40DA58BC.1060203@namesys.com> <40D9C5F5.7010605@comcast.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <40D9C5F5.7010605@comcast.net> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: George Beshers Cc: ReiserFS List George Beshers wrote: > > Caveat: I have not looked at the iozone test so this is purely in > response > to Han's description. > > The examples I know of are apps that allocate an mmap'd area for garbage > collection: ocaml, sml-nj, and I believe ghc (Haskell) do this. While > these > systems usually have generational GCs at some point major collections > happen and then I *believe* that you will see lots of dirty pages. > > Note: the 'believe' is based on some experiments on an SGI ccNuma > system with profiling tools---I was looking at local access issues and > noticed the pattern of changes to flag objects as "marked" in a > mark/sweep > collector. I then tried ocaml as an experiment and saw something > similar. > > > I have not look at Boehm conservative collector in some time, but if > memory serves me correctly it uses separate arrays to hold the bits; > using mmap is an option---I don't know if it is in common use. > > Some 18-20 months ago I spent some time looking at the Java GC > but I don't remember its using mmap() and I no longer have the source > available. > > George Besher When you say lots, do you mean close to or more than physical ram?