process status information(wait_f,wait4,schedule)

[spymate]

hi,
can anyone please tell me the difference between wait_f, wait4 and schedule, which we find under the column WCHAN when we enter the command ps -l?

[wje_lf]

When I enter this at the bash prompt:

man ps

I get (among other output) this:

nwchan     WCHAN    address of the kernel function where the process is
                    sleeping (use wchan if you want the kernel function name).
                    Running tasks will display a dash ('-') in this column.

wchan      WCHAN    name of the kernel function in which the process is
                    sleeping, a "-" if the process is running, or a "*" if the
                    process is multi-threaded and ps is not displaying
                    threads.

To go beyond that, you'll have to browse through kernel source, unless there's a kernel guru around here who wishes to step up to the plate.

Hope this helps.