Re: apache threads not balanced over all CPU cores, schedular problem or apache?

From: Rahul Pydimukkala
Date: Thu Nov 13 2008 - 08:06:19 EST


Few of the cores are always left idle by default for power saving reasons.
There has been a discussion over it sometime back. http://lkml.org/lkml/2008/6/25/326

That helps you play around with the load-balancer.



-
Rahul



On 19:46 Thu 13 Nov , kyle wrote:
> From: "Rahul Pydimukkala" <prahul@xxxxxxxxxxxxxx>
> To: "kyle" <kylewong@xxxxxxxxxx>
> Cc: <linux-kernel@xxxxxxxxxxxxxxx>
> Sent: Thursday, November 13, 2008 10:34 PM
> Subject: Re: apache threads not balanced over all CPU cores, schedular
> problem or apache?
>
>
> >On 12:58 Thu 13 Nov , kyle wrote:
> >>Hi,
> >>
> >>Please cc me if possible.
> >>
> >>I have a machine with Intel Q9300 4-core CPU, 8GB RAM. It runs apache
> >>2.0.63
> >>with traditional prefork MPM.
> >
> >Yes, this is quite undesirable given that the kernel has a good
> >load-balancer. Can you give more information regarding the kernel version
> >and load stats of individual apache processes as well?
> >-
> >Rahul
> >
>
> They now all load on cpu1 and cpu2.
>
> top - 19:35:42 up 8 days, 22:36, 8 users, load average: 1.77, 1.63, 1.75
> Tasks: 251 total, 2 running, 249 sleeping, 0 stopped, 0 zombie
> Cpu0 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si,
> 0.0%st
> Cpu1 : 14.1%us, 4.4%sy, 0.0%ni, 52.9%id, 27.2%wa, 0.0%hi, 1.5%si,
> 0.0%st
> Cpu2 : 4.3%us, 2.9%sy, 0.0%ni, 92.3%id, 0.0%wa, 0.0%hi, 0.5%si,
> 0.0%st
> Cpu3 : 0.5%us, 0.5%sy, 0.0%ni, 98.0%id, 1.0%wa, 0.0%hi, 0.0%si,
> 0.0%st
> Mem: 8117172k total, 8029032k used, 88140k free, 373356k buffers
> Swap: 208824k total, 8576k used, 200248k free, 5884936k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND
> 15112 nobody 20 0 199m 10m 7344 S 2.5 0.1 0:00.94 2 httpd
> 14488 nobody 20 0 208m 17m 8400 S 2.0 0.2 0:02.06 1 httpd
> 15184 nobody 20 0 203m 12m 7652 S 2.0 0.2 0:00.69 1 httpd
> 15320 nobody 20 0 199m 9736 6556 S 2.0 0.1 0:00.29 2 httpd
> 15466 nobody 20 0 201m 9424 4684 S 2.0 0.1 0:00.05 2 httpd
> 15204 nobody 20 0 201m 10m 7380 S 1.5 0.1 0:00.66 2 httpd
> 15051 nobody 20 0 203m 12m 7716 S 1.0 0.2 0:01.43 2 httpd
> 15059 nobody 20 0 204m 13m 9232 S 1.0 0.2 0:01.22 2 httpd
> 15081 nobody 20 0 203m 12m 7724 S 1.0 0.2 0:00.95 2 httpd
> 15319 nobody 20 0 202m 12m 6376 S 1.0 0.2 0:00.26 1 httpd
> 15465 nobody 20 0 199m 8448 5396 S 1.0 0.1 0:00.05 2 httpd
> 15467 nobody 20 0 200m 8872 4568 S 1.0 0.1 0:00.02 2 httpd
> 12215 nobody 20 0 202m 13m 9756 S 0.5 0.2 0:05.54 2 httpd
> 13052 nobody 20 0 205m 14m 9.8m S 0.5 0.2 0:04.36 2 httpd
> 13433 nobody 20 0 203m 14m 9564 S 0.5 0.2 0:05.25 1 httpd
>
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