Better CPU Utilization on FC8

baddah · 07-11-2008, 07:38 AM

Hi,

I have a Intel Xeon 2.66GHz Dual Core CPU. On this server i have a script that will run at specified intervals. In Most cases the script is the only real process running on the server,so i want to maximise the CPU utilaztion as much as i can.

The problems is that currently is only using about 30% on average of the CPU.

Code:

Extract from vmstat 1

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 2  0     60  57360 150372 1736152    0    0     0  3552 1675 13538 29  7 48 16  0
 1  0     60  57324 150372 1736152    0    0     0  3552 1671 13482 30  7 46 17  0
 1  1     60  57324 150372 1736152    0    0     0  3572 1683 13607 29  7 47 17  0
 1  0     60  57324 150372 1736152    0    0     0  3556 1677 13531 31  7 44 17  0
 0  1     60  57324 150376 1736152    0    0     0  3560 1673 13557 30  7 46 17  0
 0  1     60  57324 150376 1736152    0    0     0  3552 1671 13510 28  6 50 15  0
 2  0     60  57200 150376 1736152    0    0     0  3548 1672 13521 27  7 50 16  0
 1  0     60  57200 150376 1736152    0    0     0  3812 1652 13082 29  6 48 17  0
 2  0     60  57200 150380 1736152    0    0     0  3556 1671 13528 28  6 50 15  0
 1  0     60  57200 150384 1736152    0    0     0  3560 1675 13549 29  5 50 16  0
 1  0     60  57200 150388 1736152    0    0     0  3552 1670 13524 31  7 45 17  0
 1  0     60  57200 150388 1736152    0    0     0  3556 1675 13514 30  7 46 18  0
 1  0     60  57200 150388 1736152    0    0     0  3560 1675 13551 28  8 48 16  0
 1  1     60  57116 150388 1736152    0    0     0  3544 1666 13476 30  7 44 18  0
 1  0     60  57076 150392 1736152    0    0     0  3560 1674 13555 30  7 46 17  0
 1  0     60  57076 150392 1736152    0    0     0  3540 1671 13481 29  7 48 17  0
 1  0     60  56404 150392 1736152    0    0     0  7160 1489 11663 25  6 45 24  0
 1  0     60  56456 150392 1736152    0    0     0  4096 1669 13313 30  7 46 17  0
 1  0     60  56456 150396 1736152    0    0     0  3544 1672 13386 29  6 48 17  0
 2  0     60  56456 150400 1736148    0    0     0  3540 1666 13432 28  6 50 16  0
 1  0     60  56456 150400 1736152    0    0     0  3552 1678 13512 28  6 50 15  0
 1  0     60  56456 150400 1736156    0    0     0  3564 1682 13576 31  6 45 17  0
 0  1     60  56456 150400 1736156    0    0     0  3584 1678 13539 30  6 48 16  0
 1  0     60  56456 150400 1736156    0    0     0  3532 1674 13442 29  7 48 17  0
 2  0     60  56456 150400 1736156    0    0     0  3568 1680 13587 29  7 47 17  0
 1  0     60  56456 150404 1736156    0    0     0  3564 1680 13542 29  6 50 16  0

The scrip runs for quite a while, and i'd like to let ir run at between 70 and 80% to shorten the time it takes to execute.

I have tried running it with nice -n -20 , but this had no effect at all. How can i optimize the CPU utilization for this script so that it'll use between 70 and 80% of the CPU when it executes.

ilikejam · 07-11-2008, 07:54 AM

Hi.

The script is probably waiting for I/O if it's not maxing out the processor. What does 'top' look like when the script is running?

Dave

baddah · 07-11-2008, 08:09 AM

Hi,

Here's the output from top

Code:

Tasks: 104 total,   2 running, 101 sleeping,   0 stopped,   1 zombie
Cpu(s): 29.8%us,  6.6%sy,  0.0%ni, 45.8%id, 17.3%wa,  0.3%hi,  0.2%si,  0.0%st
Mem:   2072676k total,  2016584k used,    56092k free,   150636k buffers
Swap:  2096376k total,       60k used,  2096316k free,  1736244k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 6829 root      20   0 14180 7052 2796 R   43  0.3   0:43.35 NewFetchAccount
 4354 mysql     20   0  136m  27m 4824 S   24  1.4 278:14.44 mysqld
  522 root      15  -5     0    0    0 S    8  0.0  17:12.22 md2_raid1
    1 root      20   0  2112  660  572 S    0  0.0   0:22.53 init
    2 root      15  -5     0    0    0 S    0  0.0   0:00.00 kthreadd
    3 root      RT  -5     0    0    0 S    0  0.0   0:00.06 migration/0
    4 root      15  -5     0    0    0 S    0  0.0   0:00.03 ksoftirqd/0
    5 root      RT  -5     0    0    0 S    0  0.0   0:00.00 watchdog/0
    6 root      RT  -5     0    0    0 S    0  0.0   0:00.09 migration/1
    7 root      15  -5     0    0    0 S    0  0.0   0:02.63 ksoftirqd/1
    8 root      RT  -5     0    0    0 S    0  0.0   0:00.00 watchdog/1
    9 root      15  -5     0    0    0 S    0  0.0   0:00.02 events/0
   10 root      15  -5     0    0    0 S    0  0.0   0:11.20 events/1
   11 root      15  -5     0    0    0 S    0  0.0   0:00.00 khelper
   63 root      15  -5     0    0    0 S    0  0.0   0:00.05 kblockd/0

So the total CPU is 29% here, with the script taking most of it and mysql, which the script uses, the rest. I guess if its waiting for I/O i'll have to try and optimize it here. Just thought ,looking at the CPU utlization ,the script was not running to its full potential, but i guess it is.

Thanks