Re: [PATCH] Staircase scheduler v7.4

Michael Buesch
2004-06-25T19:50:07Z

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On Friday 25 June 2004 21:05, you wrote:
> Hi Michael,
>
> On Fri, Jun 25, 2004 at 08:44:22PM +0200, Michael Buesch wrote:
>
> > I don't know what the file wchan is good for, but here is
> > it's output:
> > mb@lfs:/proc/11000> cat wchan
> > sys_wait4
>
> I bet the process is waiting for a SIGCHLD from a previously forked
> process. Con, would it be possible that under some circumstances,
> a process does not receive a SIGCHLD anymore, eg if the child runs
> shorter than a full timeslice or something like that ? In autoconf
> scripts, there are lots of very short operations that might trigger
> such unique cases.

Hm. 11000 is a bash, so it forked some process. Just wanted to note,
that there are _no_ Zombies around, but this wait()ing bash.

load grows and grows:

top - 21:40:07 up 3:55, 7 users, load average: 10.59, 10.25, 9.99
Tasks: 91 total, 12 running, 79 sleeping, 0 stopped, 0 zombie
Cpu(s): 13.7% user, 10.3% system, 76.0% nice, 0.0% idle, 0.0% IO-wait
Mem: 515624k total, 466520k used, 49104k free, 43144k buffers
Swap: 976712k total, 92k used, 976620k free, 207184k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ Command
2060 mb 39 19 38872 28m 2904 R 76.0 5.7 153:16.26 FahCore_78.exe
2270 mb 20 0 32428 7924 10m S 13.6 1.5 32:02.58 tvtime
2149 root 20 0 187m 41m 149m S 6.0 8.3 17:10.37 X
8936 mb 20 0 32736 20m 29m S 2.0 4.0 2:33.62 ksysguard
2238 mb 20 0 28628 15m 9m S 0.7 3.1 0:45.02 gkrellm
2315 mb 20 0 57052 11m 11m S 0.3 2.3 0:22.20 beep-media-play
8937 mb 20 0 2012 1072 1592 S 0.3 0.2 0:38.52 ksysguardd
1 root 20 0 1412 520 1252 S 0.0 0.1 0:00.30 init
2 root 39 19 0 0 0 R 0.0 0.0 0:00.00 ksoftirqd/0
3 root 10 -10 0 0 0 S 0.0 0.0 0:00.16 events/0
... following more processes with 0.0% CPU.

As you can see, it's impossible to generate a load of 10.59 with these
few processes running. There are two processes running full time.
FahCore_78.exe at nice 19 and tvtime never uses more then 15% CPU.

But as the load grows, the system is usable as with load 0.0.
And it really should be usable with 76.0% nice. ;) No problem here.
This really high load is not correct.

- --
Regards Michael Buesch [ http://www.tuxsoft.de.vu ]

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