Re: setting load limit for atd batch system?

On Fr 24 Mai 2024 at 12:24, Woozy Song <suzyw0ng@outlook.com> wrote:

Woozy Song wrote:

So the atd supposedly will not start another job until load factor falls
below a limit. Different documentation gives the default as 0.8 or 1.5
Now I launch a job that uses 4 cores on a 6-core CPU. If I run top
command, I see four processes running close to 100%.
Now if I submit another job 10 seconds later, that starts thereby
overloading the CPU. Documentation suggests setting load limit to more
than n-1 for n CPU cores, but I think that is intended for single-thread
jobs. I have tried altering the load limit in atd.service file to all
sorts of values, but second job keeps starting while the first is flogging
the CPU. I check with 'ps -ef|grep atd' to see it is using the desired
load limit. I am aware that the load factor is an average, you can see it
changes slowly in top/htop/glances. So I also increase the delay between
jobs to 30 seconds, but still nothing works. So it looks like I have to
specify a time like 'now+60 minutes' when I submit, requiring some guess
how long first job runs. I know I can install a proper job scheduler such
as Some Grid Engine, but that is more work.
This is on Debian 11, by the way.

>
I found the trick: you have to add '-q B' to command, then load-limit rule
applies (it behaves like batch command instead of at). Otherwise it uses
default queue 'a' that only uses time without load limit.

I think ot is '-q b', the small letter b for the batch queue (a is for at).
The other letters are not used by default and just serve to indicate niceness.

'Andreas

--
ceterum censeo redmondinem esse delendam