Linode.com Forum

npk1977 · Joined: 03 May 2007 Posts: 4

All:

I have my linode running fedora core, and I have a strange, high, load average: (~0.5, see bottom of post.)

Code:
[unix]$ ps aux
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.2 2028 644 ? Ss 22:10 0:00 init [3]
root 2 0.0 0.0 0 0 ? SN 22:10 0:00 [ksoftirqd/0]
root 3 0.0 0.0 0 0 ? S< 22:10 0:00 [events/0]
root 4 0.0 0.0 0 0 ? S< 22:10 0:00 [khelper]
root 5 0.0 0.0 0 0 ? S< 22:10 0:00 [kthread]
root 49 0.0 0.0 0 0 ? S< 22:10 0:00 [kblockd/0]
root 61 0.0 0.0 0 0 ? S 22:10 0:00 [pdflush]
root 62 0.0 0.0 0 0 ? S 22:10 0:00 [pdflush]
root 63 0.0 0.0 0 0 ? S< 22:10 0:00 [kswapd0]
root 64 0.0 0.0 0 0 ? S< 22:10 0:00 [aio/0]
root 67 0.0 0.0 0 0 ? S< 22:10 0:00 [jfsIO]
root 68 0.0 0.0 0 0 ? S< 22:10 0:00 [jfsCommit]
root 69 0.0 0.0 0 0 ? S< 22:10 0:00 [jfsSync]
root 70 0.0 0.0 0 0 ? S< 22:10 0:00 [xfslogd/0]
root 71 0.0 0.0 0 0 ? S< 22:10 0:00 [xfsdatad/0]
root 616 0.0 0.0 0 0 ? S< 22:10 0:00 [kcryptd/0]
root 617 0.0 0.0 0 0 ? S< 22:10 0:00 [ksnapd]
root 713 0.0 0.0 0 0 ? S< 22:10 0:00 [kjournald]
root 768 0.0 0.2 2120 564 ? S<s 22:10 0:00 /sbin/udevd -d
root 2295 0.0 0.2 2276 540 ? Ss 22:10 0:00 /sbin/dhclient -1 -q -lf /var/
root 2380 0.0 0.2 1796 704 ? Ss 22:10 0:00 syslogd -m 0
root 2383 0.0 0.1 1636 392 ? Ss 22:10 0:00 klogd -x
root 2443 0.0 0.4 10640 1228 ? Ssl 22:10 0:00 pcscd
root 2477 0.0 0.3 5176 944 ? Ss 22:11 0:00 /usr/sbin/sshd
root 2496 0.0 0.6 8520 1640 ? Ss 22:11 0:00 sendmail: accepting connection
smmsp 2504 0.0 0.5 7568 1456 ? Ss 22:11 0:00 sendmail: Queue runner@01:00:0
root 2523 0.0 0.4 5220 1096 ? Ss 22:11 0:00 crond
root 2542 0.0 0.1 2204 428 ? Ss 22:11 0:00 /usr/sbin/atd
root 2548 0.0 0.1 1620 424 tty0 Ss+ 22:11 0:00 /sbin/mingetty tty0
root 2629 0.0 0.9 8024 2380 ? Ss 22:20 0:00 sshd: npk [priv]
npk 2631 0.0 0.7 8148 1876 ? S 22:20 0:00 sshd: npk@pts/0
npk 2632 0.0 0.5 4620 1468 pts/0 Ss 22:20 0:00 -bash
npk 2682 0.0 0.3 4216 936 pts/0 R+ 22:41 0:00 ps aux
[unix]$ uptime
22:49:33 up 38 min, 1 user, load average: 0.40, 0.41, 0.36

Can someone explain why this is the case?

n

Deckert · Joined: 24 Mar 2007 Posts: 42 Location: South Africa

Hi,

I have exactly the same problem on my Linode. It's been that way ever since I changed to the 2.6.20-linode28 kernel.

Load average hovers around 0.4 all the time for me.

My vmstats show 100% idle times:

Code: procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 0 0 6964 83548 125664 0 0 1 11 61 15 0 0 100 0
0 0 0 6964 83548 125664 0 0 0 0 110 17 0 0 100 0
0 0 0 6964 83548 125664 0 0 0 0 105 13 0 0 100 0
0 0 0 6964 83548 125664 0 0 0 0 105 13 0 0 100 0
0 0 0 7012 83548 125664 0 0 0 0 105 17 0 0 100 0

I also set up a log to see if there was a trend, but the graph is pretty much flat, as you can see:

Code: 0.7 ++-+--+--+--+--+-+--+--+--+--+--+--+--+--+--+--+--+-+--+--+--+--+--+-++
+ + + + + + + "load-20070429" using 1:2 ****** +
| |
0.6 ++ ++
| |
| |
| |
0.5 ++ +*
| *
| *
0.4 ++ +*
|* * ** * *|
|***** ** ** ** ***** ** ****** ** *** ** ********* *|
0.3 +* * **** * ********** **** *** *** **** **+
* *|
* |
* |
0.2 ++ ++
| |
+ + + + + + + + + + + + +
0.1 ++-+--+--+--+--+-+--+--+--+--+--+--+--+--+--+--+--+-+--+--+--+--+--+-++
00:00 02:00 04:0006:00 08:00 10:00 12:00 14:00 16:0018:00 20:00 22:00 00:00

The load is wrecking havoc with my monitoring - I was actually considering opening a ticket, but then I saw your post.

--deckert

caker · Joined: 15 Apr 2003 Posts: 2371 Location: Galloway, NJ

Jeff knows about this and is looking into it.

-Chris

Deckert · Joined: 24 Mar 2007 Posts: 42 Location: South Africa

caker wrote: Jeff knows about this and is looking into it.

-Chris

Thanks caker. I'd be happy to assist in testing (i.e. be a guineapig).

Also, the load does not affect the actual performance of my Linode. I've done a couple of staggered tests between the 2.4-latest and 2.6 latest kernels and here are the results:

Code: OS : Linux 2.4.29-linode39-1um
C compiler : gcc version 3.3.4
libc : ld-2.3.2.so
MEMORY INDEX : 13.791
INTEGER INDEX : 9.333
FLOATING-POINT INDEX: 23.904

and

Code: OS : Linux 2.6.20-linode28
C compiler : gcc version 3.3.4
libc : ld-2.3.2.so
MEMORY INDEX : 16.524
INTEGER INDEX : 11.235
FLOATING-POINT INDEX: 28.948

So the 2.6 kernels are a little faster, even with the additional load indicated.

--deckert

npk1977 · Joined: 03 May 2007 Posts: 4

So if I can summarize:

it seems as if there is an unaccounted for load on machines, but this load has no affect on performance or CPU use percentage. For some reason, I find this disconcerting :)

take care
n

pclissold · Joined: 24 Oct 2003 Posts: 470 Location: Netherlands

npk1977 wrote: it seems as if there is an unaccounted for load on machines
The load is being incorrectly calculated. Something similar happened previously - the kernel reported 1+'actual load value'.

caker · Joined: 15 Apr 2003 Posts: 2371 Location: Galloway, NJ

Jeff found the problem and has provided a fix for it. I'll be building a new kernel in the next few days with the correction.

EDIT: http://lkml.org/lkml/2007/5/4/369

-Chris

pclissold · Joined: 24 Oct 2003 Posts: 470 Location: Netherlands

That link points to an Ingo Molnar initiated 'KVM paravirtualization for Linux' thread om lkml.org - or did I miss something?

caker · Joined: 15 Apr 2003 Posts: 2371 Location: Galloway, NJ

pclissold wrote: That link points to an Ingo Molnar initiated 'KVM paravirtualization for Linux' thread om lkml.org - or did I miss something?
Whoops. Fixed.

-Chris

Deckert · Joined: 24 Mar 2007 Posts: 42 Location: South Africa

caker wrote: Jeff found the problem and has provided a fix for it. I'll be building a new kernel in the next few days with the correction.
Nicely done, caker! Thanks for pushing this through to Jeff for us.

--deckert

strange load average