Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site ucbvax.ARPA Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!info-vax From: info-vax@ucbvax.ARPA Newsgroups: fa.info-vax Subject: Re: Paging [and VT's] Message-ID: <5281@ucbvax.ARPA> Date: Wed, 6-Mar-85 11:21:26 EST Article-I.D.: ucbvax.5281 Posted: Wed Mar 6 11:21:26 1985 Date-Received: Thu, 7-Mar-85 05:02:32 EST Sender: daemon@ucbvax.ARPA Organization: University of California at Berkeley Lines: 44 From: Mark JohnsonTwo things to look at... 1) I you are running your own applications (anything YOU link) then look at the VMS Linker and the options files. The CLUSTER line can be used to change the page-fault-cluster for a section of memory. If you set it big enough, one page fault per cluster ought to bring the whole cluster into memory. This is in both the V3 (p 3-6) and V4 (p LINK-20) linker documentation. 2) The SYSGEN parameter PFCDEFAULT could also be cranked up to make the changes system wide. Lets look at what would happen if you do this. Each page fault would bring in a large number of pages into memory. This increases overall access to the disk & chews up more memory. If you run programs infrequently and have lots of memory to spare, this should be ok. Response time after the initial load should stay good and if the WS parameters are set right the CPU overhead should be near NIL. If you access a lot of programs & are running short of memory, this sort of change would clobber the system since the I/O to the disk would go through the roof. I think the VMS developers assume the VAXen are normally quite loaded so they skew the numbers away from optimal performance on lightly loaded systems and give you the tools to put the parameters where you need them. I can also forsee some tradeoff's depending on what kind of disks you use. The MASSBUS RP07's & other MBA disks are better for fewer large size transfers than RA81's. Where the RA disks come out on top is lots of smaller transfers from many jobs (so seek ordering comes into play). Its a little late to change your disk drives now, but it is something to consider for later improvements. I would also check other parameters that affect your working set. In particular, the SYSGEN parameters WSMAX, SYSMWCNT, WSINC, WSDEC, PFRATL, PFRATH, AWSMIN, AWSTIME, GROWLIM, and BORROWLIM make affects on the whole system. For individual jobs, look at the authorization file for WSDEFAULT, WSEXTENT, and WSQUOTA. Read the documentation carefully and check the job with SHOW SYSTEM or something else to check your job has all the memory you think its getting. --Mark