Asri-unix.568 net.unix-wizards utcsrgv!utzoo!decvax!ucbvax!hpvax!sri-unix!mike@BRL Mon Jan 18 21:06:35 1982 Re: nice There are few UNIX sites that DON'T want to give better service to "interactive" style programs. Our UNIX system accomplishes this quite well, without the need for tomfoolery on the part of the users. We did it with a variety of modifications to the operating system, which I am quite willing to share with the world. The most useful parts of these include: setpri/slp.c - the p_pri value depends on a number of things now, such as cpu usage history (decay curve weighted memory), block i/o system usage history (""), core requirements (NOT Kilo-core-ticks), and "NICE" value. clock/clock.c - the cpu usage history value, and the memory functions are implemented here. There are three values (INRAT: in core and selected this second, NSELRAT: in core but not selected at all this second, and OUTRAT: swapped out). These control the decay of the memory function. Also, for each MINUTE of cumulative CPU time a process uses, their "NICE" value is made worse by 1 point (p_nice++). There are a lot of other things we have done, but just the changes mentioned above make a BIG difference in performance. The nicest part is that everything is automatic. For those of you who like to diddle priorities, I can supply you with a program we wrote called NICER, which allows Superusers and systems people the ability to change the NICE value of any running process. We implemented a change to the swtch/slp.c routine so that a p_nice value prevents the process from getting ANY more cpu time. A value of 127 can only be achieved by NICER, so this is a good way for the administrator to "set aside" a cruncher for a bit. Are people interested in hearing all the gory details of these changes? I will mail source (or tapes) to any who provide me with their license info... -Mike ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.