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Article #4060Re: Memory management on AIX
From: Barry Margolin
Date: Tue, 09 Mar 2004 17:33
Date: Tue, 09 Mar 2004 17:33
26 lines
2923 bytes
2923 bytes
In article <7960d3ee.0403090654.20a64e42@posting.google.com>, dfreybur@yahoo.com (Doug Freyburger) wrote: > Pascal Perrot wrote: > > > > I am doing some performance analysis on machines running AIX and I discovers > > something "strange" for me: > > How could you explain a RESident set size greater than the VIRtual set size > > for a specific process??? > > AIX uses a lazy algorthym to assign disk space to pages. Disk copies are > not mapped until it is actually needed to put the page onto disk. If the > difference is large, the virtual size just might be measuring the disk > resident part instead of the total. You have it backward -- "resident" means "resident in main memory". The reason why resident size can be larger than virtual size is because VSZ typically only counts the data and stack segments. But portions of the text segment also have to be in main memory for the program to run, and it's possible for this to exceed the amount of data/stack memory. -- Barry Margolin, barmar@alum.mit.edu Arlington, MA *** PLEASE post questions in newsgroups, not directly to me ***
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f8c9b,a3772666274316d6 X-Google-Attributes: gidf8c9b,public X-Google-Thread: 110f2c,a3772666274316d6 X-Google-Attributes: gid110f2c,public X-Google-Thread: 1020c6,a3772666274316d6 X-Google-Attributes: gid1020c6,public X-Google-Thread: 115614,a3772666274316d6 X-Google-Attributes: gid115614,public X-Google-Thread: 10650a,a3772666274316d6 X-Google-Attributes: gid10650a,public X-Google-ArrivalTime: 2004-03-09 09:34:00 PST Path: arc1-ca.pugleaf.net!archiver1.google.com!news2.google.com!news.maxwell.syr.edu!wn11feed!worldnet.att.net!216.196.106.140!border1.nntp.sjc.giganews.com!nntp.giganews.com!local1.nntp.sjc.giganews.com!nntp.comcast.com!news.comcast.com.POSTED!not-for-mail NNTP-Posting-Date: Tue, 09 Mar 2004 11:33:59 -0600 From: Barry Margolin <barmar@alum.mit.edu> Newsgroups: comp.unix.admin,comp.unix.aix,comp.unix.internals,comp.unix.questions,fr.comp.os.unix Mail-Copies-To: nobody Subject: Re: Memory management on AIX Organization: Looking for work References: <c2ju04$2qe$1@public.stna.aviation-civile.gouv.fr> <7960d3ee.0403090654.20a64e42@posting.google.com> User-Agent: MT-NewsWatcher/3.4b4 (PPC Mac OS X) X-Copies-To: never Date: Tue, 09 Mar 2004 12:33:58 -0500 Message-ID: <barmar-1E39F0.12335809032004@comcast.ash.giganews.com> Lines: 26 NNTP-Posting-Host: 24.34.107.202 X-Trace: sv3-zxF9i+DH56PW4PGTpvb/YSzD9AXH3RK6yHBZ6hopOHCaGjSt9xUrnnGUS7KgAj2YiOASLe44dyuKbX7!qGXg7nlbwCkWeg/TjkPv/KxMwDQLL6tQ4FXOqvKFKpoM+cCiLWjxTQO+0yoky7j/QO6wRn7c0cN+!DjvhOd+Nrz4= X-Complaints-To: abuse@comcast.net X-DMCA-Complaints-To: dmca@comcast.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.1