Ariane van der Steldt wrote:
On Wed, Jun 03, 2009 at 10:07:33PM -0700, patrick keshishian wrote:
On Wed, Jun 3, 2009 at 3:50 AM, Richard Toohey
<richardtoo...@paradise.net.nz> wrote:
On 3/06/2009, at 10:02 PM, BARDOU Pierre wrote:
Hello,
I have performance issues on a OpenBSD 4.4 firewall.
CPU load is OK (always below 50%), but system load is always between 1 and
1.5, it may go up to 2 sometimes.
[cut]
And what is the actual *problem*?
What is pf failing to do?
Or are you just worried about the numbers? B Search the archives for "high
load" ...
just for the record, i have seen a server where its typical load
floats around 0.10 or so, but then something will happen and the
plateau will get bumped to 1.10 and remain there. this was an 4.5
system.
I have not identified what "event" caused this. I've seen similar
issue with a couple of linux boxes at work where the load avg plateau
will keep rising: it'll hover around ~3, then say ~6 then ~13. i don't
think the issues are related, but could be caused by similar bugs in
kernel.
All systems continue to be responsive and it only seems that the
reported load avg value is just bumped by a base value. It is
definitely odd.
Load on linux and load on BSD are two completely different things. On
linux I recall load being the number of processes running or blocking,
or something based on that.
I know this is an old thread, but I came across this and thought I'd
affirm this:
from http://en.wikipedia.org/wiki/Load_(computing)
----------
Most UNIX systems count only processes in the running (on CPU) or
runnable (waiting for CPU) states. However, Linux also includes
processes in uninterruptible sleep states (usually waiting for disk
activity), which can lead to markedly different results if many
processes are blocked in I/O due to a busy or stalled I/O system. This,
for example, includes processes that are blocked due to an NFS server
failure or slow media (e.g., USB 1.x storage devices), leading to an
elevated load average, which does not reflect an actual increase in CPU
use (but still gives an idea on how long you have to wait).
---------
In other words, ditto. I've always noticed (and then ignored) a
difference between BSD/Solaris load average running the same processes
vs Linux on the same hw.
systat is much more useful, IMNSHO.
-tico
On BSD, load is the number of processes which have (wanted to) run at
least once in the most recent 5-second window, with a degradation over
time. So, if you have a process that wakes up every 5 seconds and prints
the time on your console, you have a load average of 1. Load is not the
number of cpu cycles used.
A high load is just that: high. It means you have a lot of processes
that sometimes run. High load does not mean your performance is going
down or whatever: I ran a test today which generated a load of 200, but
only used 10% of the cpu and was very responsive.
You can't compare load on linux with load on bsd, I'd really appreciate
if people stopped comparing apples and oranges. :P
If you are interested in the internals of the system: load is the black
magic that keeps the scheduling fair compared to the number of
processes.
Ciao,
