top shows 150% cpu load

crashmeister · 02-02-2008, 06:55 AM

See subject - this happens on a core2 system when both cores are relatively busy.Bug or feature

top - 10:54:03 up 1:01, 1 user, load average: 1.54, 1.60, 1.62
Tasks: 128 total, 1 running, 127 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.1%us, 0.3%sy, 73.6%ni, 25.5%id, 0.2%wa, 0.1%hi, 0.1%si, 0.0%st
Mem: 2076716k total, 2023404k used, 53312k free, 25512k buffers
Swap: 514040k total, 144k used, 513896k free, 1696288k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
4512 mama 25 10 152m 41m 13m S 148 2.0 68:27.18 avidemux
1 root 15 0 2084 712 608 S 0 0.0 0:00.94 init
2 root 10 -5 0 0 0 S 0 0.0 0:00.00 kthreadd

druuna · 02-02-2008, 07:57 AM

Hi,

How did you conclude that 1 cpu is running at 150% ?? All cpu's togehter run at +/- 150% (max would be 200% if 2 (virtual) cpu's are present.
With a single line (cpu stats) on a smp machine, the average load will be shown. Both cpu's run at an average of 73.6%.

Try the 1 option when running top, this should show you one line per (virtual) cpu. I.e.:

Quote:

top - 14:56:31 up 6 days, 15:37, 1 user, load average: 0.17, 0.16, 0.10
Tasks: 87 total, 1 running, 86 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.3% us, 0.0% sy, 0.0% ni, 99.5% id, 0.0% wa, 0.0% hi, 0.3% si
Mem: 4117952k total, 3499428k used, 618524k free, 114284k buffers
Swap: 4008208k total, 156k used, 4008052k free, 2399944k cached

Versus:

top - 14:56:47 up 6 days, 15:37, 1 user, load average: 0.12, 0.15, 0.10
Tasks: 90 total, 1 running, 89 sleeping, 0 stopped, 0 zombie
Cpu0 : 1.5% us, 0.1% sy, 0.0% ni, 98.0% id, 0.3% wa, 0.0% hi, 0.0% si
Cpu1 : 0.3% us, 0.0% sy, 0.0% ni, 99.6% id, 0.1% wa, 0.0% hi, 0.0% si
Cpu2 : 0.0% us, 0.0% sy, 0.0% ni, 99.9% id, 0.0% wa, 0.0% hi, 0.0% si
Cpu3 : 0.0% us, 0.0% sy, 0.0% ni, 99.0% id, 0.0% wa, 0.0% hi, 1.0% si
Mem: 4117952k total, 3501820k used, 616132k free, 114396k buffers
Swap: 4008208k total, 156k used, 4008052k free, 2401428k cached

The above is an example of a machine with 2 dualcore cpu's (=4 virtual cpu's).

Hope this clears things up a bit.

crashmeister · 02-02-2008, 08:10 AM

That just what I was wondering about - why doesn't it split the threads up by default?

htop shows it correctly with avidemux using around 75% on each cpu.

druuna · 02-02-2008, 08:18 AM

Hi,

That's probably due to the way things were. Duall core/multiple cpu's on pc's is kinda new, top has been around for ages.

But you can change top's startup behaviour: Start top - play with the options (press ? to see them all) until you have the view you like - when done press W (capital w). If all went well a .toprc is created in your homedir and the next time you start top you are looking at your prevered view.

Hope this helps.