Performance tuning

[Ivan Toman]

Stefan Gofferje wrote:
> As I wrote, CPU usage SHOULD not be a problem as I meanwhile start GrADS
> with nice 15. So if GrADS is written cleanly, it should step back quite
> a lot if other tasks demand CPU time.
>

I don't think that using low priority nice will help, because if there
is enough free CPU resources, kernel will still give lot of CPU cycles
to your grads process. For example, think about it like this: You have
grads dedicated machine and don't use CPU for anything except base
system (relatively idle) and grads, but you run grads with nice=15. What
will then be CPU usage of grads? Theoretically it will top one of CPU
cores with near 100% utlisation, regardless of niceness=15. If you have
now some kind of watchguard on system that has trigger set, for example,
on 20% CPU utilisation over 3 seconds or more, it will kill your process
even if it has lowest priority. It all depends how watchguard is setup.
Try that cpu limiter that I posted link to, I think it can work for you.