When testing some algorithm I ran the test program several times with different parameters. It was to be expected that each run takes about four hours, and to utilize the capacities of my computer (4 CPUs) I started the program 4 times running in parallel and with lowered priority (the latter to be able to do meanwhile something else on the computer). All four processes ran in parallel for a few minutes but then two of them were killed with the error message:
Command terminated by signal 9
[1] Exit 137 /usr/bin/time -f '%U+%S sec, avg %Kk max %Mk memory, major %F minor %R faults, %I+%O i/o' ./testu01long -d9689 -b3 > cat9689.tub
Here, "/usr/bin/time ..." is the command I launched for the first process, the second error message was quite similar, now for the second process. The process started first ran about 6 minutes, the second about 14 minutes, so the TERM signals have been issued at different times (the processes had been started within one minute). The two other processes continued without problems. The point is that I did NOT issue a TERM signal to the processes, I conclude that the OS issued the TERM signals. The effect can be repeated to some extend: if another CPU-intensive process is started (e.g. a lengthy compilation) then an already running CPU-intensive process may be killed, if so then the one first started.
When the killed program had been relaunched with the same parameters but without concurrency of other CPU-intensive processes (e.g. only editing, reading e-mails running in parallel) then all things were fine, so the kill is really not caused by the program. The program does not use external devices and even no I/O except for writing a summary to stdout at program end (i.e. not when the processes were killed).
The question is, why have the processes been killed? Is the OS unable to manage as many running processes?
I consider this a bug in the OS, part process management.
The bug implies that the computer can be used for light weight tasks only.
With regards
Dr. Wolfgang Jansen
PS:
Additional platform info (commands "ulimit -a", "top" when two CPU-intensive processes were still running):
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 30092
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 30092
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
-----------------------------------------------
Tasks: 244 total, 3 running, 241 sleeping, 0 stopped, 0 zombie
%Cpu(s): 15.5 us, 1.2 sy, 27.5 ni, 54.6 id, 1.2 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 3930376 total, 2263872 used, 1666504 free, 36756 buffers
KiB Swap: 9212 total, 9212 used, 0 free, 705612 cached
PID USER PR NI VIRT RES SHR S P %CPU %MEM TIME COMMAND
18804 wolfgang 30 10 14632 960 648 R 1 103.0 0.0 95:09 testu01long
18817 wolfgang 30 10 14632 960 648 R 0 103.0 0.0 94:03 testu01long
2491 root 20 0 444m 128m 103m S 2 6.4 3.3 7:04 Xorg
2945 wolfgang 20 0 1950m 205m 11m S 2 6.4 5.4 13:08 cinnamon
1 root 20 0 27336 1536 0 S 1 0.0 0.0 0:01 init
2 root 20 0 0 0 0 S 3 0.0 0.0 0:00 kthreadd
3 root 20 0 0 0 0 S 0 0.0 0.0 0:00 ksoftirqd/0
5 root 0 -20 0 0 0 S 0 0.0 0.0 0:00 kworker/0:0H
7 root rt 0 0 0 0 S 0 0.0 0.0 0:00 migration/0
8 root 20 0 0 0 0 S 0 0.0 0.0 0:00 rcu_bh
9 root 20 0 0 0 0 S 0 0.0 0.0 0:00 rcuob/0
10 root 20 0 0 0 0 S 0 0.0 0.0 0:00 rcuob/1
11 root 20 0 0 0 0 S 0 0.0 0.0 0:00 rcuob/2
12 root 20 0 0 0 0 S 0 0.0 0.0 0:00 rcuob/3
13 root 20 0 0 0 0 S 3 0.0 0.0 0:27 rcu_sched
14 root 20 0 0 0 0 S 3 0.0 0.0 0:06 rcuos/0
15 root 20 0 0 0 0 S 1 0.0 0.0 0:07 rcuos/1
Remark: The critical figure seems to be the swap space.
ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-19-generic 3.11.0-19.33
ProcVersionSignature: Ubuntu 3.11.0-19.33-generic 3.11.10.5
Uname: Linux 3.11.0-19-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: wolfgang 2911 F.... pulseaudio
/dev/snd/controlC0: wolfgang 2911 F.... pulseaudio
CurrentDmesg: Error: command ['sh', '-c', 'dmesg | comm -13 --nocheck-order /var/log/dmesg -'] failed with exit code 1: comm: /var/log/dmesg: Permission denied
Date: Wed Apr 16 11:35:44 2014
InstallationDate: Installed on 2014-03-20 (26 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
IwConfig:
eth0 no wireless extensions.
lo no wireless extensions.
MachineType: Acer Aspire XC600
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-19-generic root=UUID=10374065-1d70-4588-aca9-25093062a44a ro quiet splash vt.handoff=7
RfKill:
SourcePackage: linux
UpgradeStatus: Upgraded to saucy on 2014-03-21 (25 days ago)
WifiSyslog:
dmi.bios.date: 11/02/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P11-A3
dmi.board.name: Aspire XC600
dmi.board.vendor: Acer
dmi.board.version: v1.0
dmi.chassis.type: 3
dmi.chassis.vendor: Acer
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP11-A3:bd11/02/2012:svnAcer:pnAspireXC600:pvr:rvnAcer:rnAspireXC600:rvrv1.0:cvnAcer:ct3:cvr:
dmi.product.name: Aspire XC600
dmi.sys.vendor: Acer
---
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: wolfgang 2911 F.... pulseaudio
/dev/snd/controlC0: wolfgang 2911 F.... pulseaudio
CurrentDmesg:
Error: command ['sh', '-c', 'dmesg | comm -13 --nocheck-order /var/log/dmesg -'] failed with exit code 1: comm: /var/log/dmesg: Permission denied
dmesg: write failed: Broken pipe
DistroRelease: Ubuntu 13.10
InstallationDate: Installed on 2014-03-20 (26 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
IwConfig:
eth0 no wireless extensions.
lo no wireless extensions.
MachineType: Acer Aspire XC600
MarkForUpload: True
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-19-generic root=UUID=10374065-1d70-4588-aca9-25093062a44a ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.11.0-19.33-generic 3.11.10.5
RfKill:
Tags: saucy
Uname: Linux 3.11.0-19-generic x86_64
UpgradeStatus: Upgraded to saucy on 2014-03-21 (25 days ago)
UserGroups: users
WifiSyslog:
dmi.bios.date: 11/02/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P11-A3
dmi.board.name: Aspire XC600
dmi.board.vendor: Acer
dmi.board.version: v1.0
dmi.chassis.type: 3
dmi.chassis.vendor: Acer
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP11-A3:bd11/02/2012:svnAcer:pnAspireXC600:pvr:rvnAcer:rnAspireXC600:rvrv1.0:cvnAcer:ct3:cvr:
dmi.product.name: Aspire XC600
dmi.sys.vendor: Acer
---
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
DistroRelease: Ubuntu 13.10
InstallationDate: Installed on 2014-03-20 (27 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MarkForUpload: True
Package: linux (not installed)
Tags: saucy
Uname: Linux 3.15.0-031500rc1-lowlatency x86_64
UnreportableReason: The running kernel is not an Ubuntu kernel
UpgradeStatus: Upgraded to saucy on 2014-03-21 (26 days ago)
UserGroups: users
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1308474
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.