Process priority influenced by param.h?

[Jos Francois]

We have processes running at priority 152, eating cpu as hell. As far as I can notice, the priority of those processes doesn't change, even with a nice value of 39. When I look into /usr/include/sys/param.h, I find something that (maybe) could influence the base priority of a process ie. PRIBETA (6+PTIMESHARE) PUSER (50+PTIMESHARE) and so on. This latter gives a (base) priority PUSER of 178 or the normal priority of a process. Are those definitions indeed base priorities? And if so, how can we assign a base priority to a process?

[Lalit Seth]

Hi jos,

I am also looking for something like this. Did you able to solve this issue.

Can u provide in more details on this?

Many Thanks

[Stephen Keane]

Real time priority values (0 - 127) are reserved for processes started using a rtprio() call and are used in a real-time scheduling policy.

System priority values (128 - 177) are used in a time-sharing scheduling policy.

User priority values (178 - 255) are used in a time-sharing scheduling policy.

The kernel can change the priority of any process within a time-sharing scheduling policy, but it can't change the priority of a real-time process.

Thus if a process is running with a priority of 152, it must be a system priority value rather than a user one (the default). The kernel believes that the process is running on behalf of the system, rather than as a user's process. e.g. vxfsd will typically have a priority of 152.