Should SETI play nice?

[Manex]

OK all you Unix Seti crunchers, I have a question. I'm running the version 3 text client on some HP 4-way compute servers. MY question is this: What does the "-nice N" command line switch do? Does this give the Seti client high CPU priority? If so, do I want to use this switch? Also, what are the drawbacks to using this switch on a 4-way server?

Thanks!

Eric

[Mojo]

Making your process 'nicer' to other processes means giving it a lower priority. The higher the nice-level you specify, the lower priority. Users with root access can also specify negative niceness levels.

[Pace]

Check the SETI @ MURC site ( http://www.pace.fsnet.co.uk/seti ) and in particular, Martin's Linux/Unix guide - he mentions it - dunno if it's helpful but it's got some other stuff you might find useful!

Paul.

------------------
Pace3000 Network: (early stages)
Computer Solutions | Arena | Seti | P3K | TechSupport | Portal | Pace Central
Matrox Users / SETI@MURC
Join the team! | Crunch faster! | View the stats!

[Pace]

By default, the client will run on "nice-level 1"; its priority is slightly lower than default. Other programs on the system will hardly be affected by the fact that seti is running.

However, if you want to make sure that system-performance is affected even less, use the "-nice" command switch. Using the last example of the previous section:
./setiathome -nice 19 -email &> /dev/null &
This is how I used to run seti: it starts the client in the background, at the lowest system-priority, and drops me an e-mail if something goes wrong.

From the guide

Paul.

[Butcher]

Don't forget to run 4 copies - seti will only use 1 cpu otherwise.

[Manex]

Thanks for the replies everyone... So I gather from my reading of the guide that if I run Seti with "-nice 0", that will make it run at the default priority? I'd like it to have the same priority as any other application on the server.

Cheers!

Eric

[Rattledagger]

I'm not a Unix-wizard, but -nice 0 should be the same as not using nice at all, therefore seti@home set it's own priority.
I don't know that priority seti@home defaults as, but if as example seti@home has default priority -5 and normal programs starts as 0, -nice 0 should still run seti@home as -5. In this example to run seti@home as the other programs, you should use -nice -5.
To find out that priority programs actually have, use top or another info-program.
(I hope it was top it was called... It's a long time since I've used any form of unix.)

[Butcher]

Um in unix lower priority means you hog more cpu... so nice 19 is the nicest (and hence lowest priority). nice -5 would probably lock out the shell you started the process from as it would hog so much cpu. :P

[Kruse]

Yup. Be careful not to run Seti at even marginally higher priority than any other process you might need... otherwise you may very well find yourself reaching for the power switch. There is a reason why it defaults to priority 1.