Messages in this thread | | | Date | Mon, 16 Nov 1998 09:01:03 -0500 | From | Ben McCann <> | Subject | Re: Something wrong with scheduler in linux 2.1.127/2.1.128 |
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"Michael H. Warfield" <mhw@wittsend.com> wrote:
> I think you are seeing what I've been seeing the the latest few revs. > It takes a long time for this to get triggered so I've been very slowly doing > a process of elimination to isolation when and where and how. It sometimes > takes as much as a day before the things starts acting up for me. > > I see the same symptoms as you do but have been gathering other data. > Seem that an active running process is ok but starting processes are a killer. > Top shows 0% idle but 95% to 105% (yes greater than 100%) System time. User > time is in low single digits. My first sign of trouble is a rapid rise in > load average. This thing is normally getting triggered with something making > a high file system demand (usually when I resync my mailbox in elm) and the > load average takes a jump anyways. What happens in this case, though, is that > the load average rises above the 1.0 - 1.5 I normally see and may peak out > in 30-60 seconds at around 15 (NO THERE IS NO DECIMAL POINT IN THAT). Only > choice I have then is to try and kill processes and try and reboot. Running > processes seem almost impossible to kill, even though their CPU time is > clocking up rapidly. With the high "system" percent, I would assume that > they are all looping around down in the kernel. >
I saw the same behavior with 2.1.128 on a UP Pentium 200 MMX with IDE, no SCSI, and SMP disabled. I was compiling a large C++ file to local disk while in X-windows. I could switch to the standard virtual consoles (and back to X) but I could not start new processes. Alt-SysRq-T showed 5 or 6 processes running continuously (stuck in 'R' state). When these programs compile, g++ grows to about 70MB and I only have 64MB of memory so some swapping is occurring. Other processes had been forked recently because one of the stuck running processes was 'cron'.
I tried this once and then went back to 2.1.125 (which has been fine...).
I applied Alan Cox's 128ac2 patch last night and repeated the compilation test which had previously failed one time. I left the machine looping, rebuilding this particular program, all night.
It was still running after 8 hours this morning.
Perhaps some of the changes Alan made fixed this problem. I noted that one of the changes was in fork() and its interactions with 'mm'.
-Ben McCann
-- Ben McCann Indus River Networks 31 Nagog Park Acton, MA, 01720 email: bmccann@indusriver.com web: www.indusriver.com phone: (978) 266-8140 fax: (978) 266-8111
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