Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-mm1

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To: Francois Romieu <romieu@...>
Cc: Robert Hancock <hancockr@...>, <netdev@...>, LKML <linux-kernel@...>
Date: Friday, August 29, 2008 - 9:48 pm

Hello again


On Mon, Aug 11, 2008 at 9:53 AM, Dushan Tcholich <dusanc@gmail.com> wrote:

I dug a little more and found out some new info.
Unsolved bugreport with same symptoms:
http://marc.info/?l=linux-kernel&m=119613299024398&w=2
Problems appear if I start br0 interface, as context switch rate
increases 200 times. If I start eth0 instead everything looks ok.
The bugreport above had bridging enabled too.

When using eth0 I get:
 vmstat -n 1 10
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 2  0  17720 162288  25024 576852    0    0    21    22    6    9 10  4 85  0
 0  0  17720 162196  25024 576880    0    0     0     0   13  473  0  0 99  0
 0  0  17720 162196  25028 576880    0    0     0     4   36 1122  1  0 99  0
 0  0  17720 162196  25028 576880    0    0     0     0   83  844  0  0 99  0
 0  0  17720 162196  25028 576880    0    0     0     0   55  691  1  0 99  0
 0  0  17720 162556  25028 576880    0    0     0     0   13  490  1  0 100  0
 0  0  17720 162100  25028 576880    0    0     0     0   39  561  6  0 94  0
 1  0  17720 162028  25028 576880    0    0     0     0   16 1030  4  0 96  0
 0  0  17720 162028  25028 576880    0    0     0     0   40  597  1  0 99  0
 0  0  17720 162028  25028 576880    0    0     0     0   12  512  2  0 97  0

 top

top - 03:30:07 up 6 days,  5:40,  4 users,  load average: 0.02, 0.11, 0.28
Tasks: 149 total,   2 running, 147 sleeping,   0 stopped,   0 zombie
Cpu(s): 12.1%us,  3.3%sy,  0.0%ni, 84.6%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   1033388k total,   871336k used,   162052k free,    25016k buffers
Swap:   610460k total,    17720k used,   592740k free,   576852k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND

    4 root      15  -5     0    0    0 S    0  0.0 554:23.44 ksoftirqd/0

If I use br0 I get:
 vmstat -n 1 10
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 0  0  17720 162112  25048 577120    0    0    21    22    6   11 10  4 86  0
 0  0  17720 162152  25048 577120    0    0     0     0   14 111082  0  3 97  0
 0  0  17720 162152  25048 577120    0    0     0     0   23 107134  1  3 96  0
 1  0  17720 160148  25048 577120    0    0     0     0   11 109888  2  3 95  0
 0  0  17720 162032  25048 577120    0    0     0     0   33 108163  1  2 97  0
 0  0  17720 162032  25048 577120    0    0     0     0    7 104642  2  2 95  0
 0  0  17720 162020  25048 577120    0    0     0     0   41 109135  0  2 98  0
 0  0  17720 162036  25048 577120    0    0     0     0    9 105133  0  3 96  0
 0  0  17720 162020  25048 577120    0    0     0     0   42 107605  1  2 97  0
 1  0  17720 162032  25048 577120    0    0     0     0    5 110768  0  2 98  0

top

top - 03:32:03 up 6 days,  5:41,  4 users,  load average: 0.09, 0.10, 0.26
Tasks: 148 total,   2 running, 146 sleeping,   0 stopped,   0 zombie
Cpu(s):  4.8%us,  2.0%sy,  0.0%ni, 93.0%id,  0.0%wa,  0.0%hi,  0.2%si,  0.0%st
Mem:   1033388k total,   871564k used,   161824k free,    25048k buffers
Swap:   610460k total,    17720k used,   592740k free,   577120k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
11489 dusan     20   0  235m  85m  24m R    6  8.5   1:03.51 firefox
    4 root      15  -5     0    0    0 S   7  0.0 554:24.04 ksoftirqd/0

I start br0 like this in /etc/conf.d/net

bridge_br0="eth0"
config_eth0=( "null" )
config_br0=( "192.168.1.3/24" )
RC_NEED_br0="net.eth0"
brctl_br0=( "setfd 0" "sethello 0" "stp off" )
#routes_br0=( "default gw 192.168.1.3" )
depend_br0() {
        need net.eth0
}

I start eth0 like this in /etc/conf.d/net
config_eth0=( "192.168.1.3/24" )

Have a nice day
Dushan
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Messages in current thread:
Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-..., Dushan Tcholich, (Fri Aug 29, 9:48 pm)
Re: ksoftirqd high cpu load on kernels 2.6.24 to 2.6.27-rc1-..., Stephen Hemminger, (Sun Aug 31, 1:05 pm)
[RFC] bridge: STP timer management range checking, Stephen Hemminger, (Sun Aug 31, 1:43 pm)
[PATCH] bridge: don't allow setting hello time to zero, Stephen Hemminger, (Thu Sep 4, 6:47 pm)
Re: [PATCH] bridge: don't allow setting hello time to zero, Dushan Tcholich, (Mon Sep 8, 5:35 pm)
Re: [PATCH] bridge: don't allow setting hello time to zero, Stephen Hemminger, (Mon Sep 8, 6:33 pm)
Re: [RFC] bridge: STP timer management range checking, David Miller, (Tue Sep 2, 8:28 pm)
Re: [RFC] bridge: STP timer management range checking, Stephen Hemminger, (Sun Aug 31, 7:29 pm)
Re: [RFC] bridge: STP timer management range checking, David Miller, (Tue Sep 2, 7:41 pm)