STEINBERGER@KL.SRI.COM (Richard Steinberger) (07/29/88)
I have noticed that when I type "SHOW SYSTEM" under version 5.0, the NULL process isn't listed (the first one is SWAPPER). Could someone familiar with this explain what now substitutes for the NULL process? -Ric Steinberger steinberger@kl.sri.com -------
OBERMAN@ICDC.LLNL.GOV ("Kevin Oberman, LLNL, 422-6955", 415) (07/29/88)
>I have noticed that when I type "SHOW SYSTEM" under version 5.0, the NULL >process isn't listed (the first one is SWAPPER). Could someone familiar >with this explain what now substitutes for the NULL process? The NULL process is no more (sort of). The function of NULL has been moved into KERNEL space. As a result, the NULL process is `invisible' to the system. The calculation of idle time is now taken by accessing some locations in the kernel. I don't have the details handy right now. R. Kevin Oberman Lawrence Livermore National Laboratory Internet: oberman@icdc.llnl.gov (415) 422-6955 Disclaimer: Don't take this too seriously. I just like to improve my typing and probably don't really know anything useful about anything.
LEICHTER@VENUS.YCC.YALE.EDU ("Jerry Leichter ", LEICHTER-JERRY@CS.YALE.EDU) (07/30/88)
I have noticed that when I type "SHOW SYSTEM" under version 5.0, the NULL process isn't listed (the first one is SWAPPER). Could someone familiar with this explain what now substitutes for the NULL process? Actually, in some sense the null process is still there; but it's been made invisible to GETJPI. NULL had two purposes in life: To make sure there was always a process for the scheduler to run (thus eliminating a special case); and as a handy way to determine unused time on the system, since it would all get "used" by NULL. With multiprocessors, a single null process can't server either of these purposes: There many be a number of processors each needing a "NULL" process to run; and the idle time has to be the sum of the idle times for each processor. So what was visible as "the NULL process" - which was always a hack anyway; the NULL process's code was assembled into VMS, was all up in system space, and never had any real process context - has now been re-orga- nized into appropriate "idle loops" which it's not useful to cover with a "process" facade any more. -- Jerry
jayz@cullsj.UUCP (Jay Zorzy) (07/30/88)
From article <12418195881.29.STEINBERGER@KL.SRI.COM>, by STEINBERGER@KL.SRI.COM (Richard Steinberger): > I have noticed that when I type "SHOW SYSTEM" under version 5.0, the NULL > process isn't listed (the first one is SWAPPER). Could someone familiar > with this explain what now substitutes for the NULL process? In VAX/VMS V5.0, the NULL process has been replaced by a loop on the interrupt stack (an SMP change, I believe). Jay Zorzy Cullinet Software San Jose, CA