Re: Support for SIGSTOP/SIGCONT in nice?

[Bob Proulx]

Jim Meyering wrote:
> Simon Josefsson <address@hidden> wrote:
> ...
> > Still, maybe not all programs have similar rate-limiting features, so
> > that this nice-extension may be useful anyway...
> 
> I agree.  Maybe even as a separate program, for when you start something
> important and somehow resource-intensive, so that you can regulate its
> impact after the fact (via some new tool with a --pid=PID option).

Using the loadwatch program the following works.

  perl -e '$t=1; while (1) { $t = sqrt $t }' &   # run a cpu bound job
  [1] 18365

  loadwatch -d 10 -l 0.4 -h 0.5 -p 18365         # watch it, stop it, run it
  Fri Mar 31 08:48:30 2006: load too high, stopping.
  Fri Mar 31 08:49:00 2006: load low, continuing.
  Fri Mar 31 08:49:20 2006: load too high, stopping.
  Fri Mar 31 08:50:20 2006: load low, continuing.


  loadwatch [-d <time>] [-h <load>] [-l <load>] [-n <copies>] [-p <pid>] [-- 
<command>]
          -d <int>        load sampling interval (10 seconds)
          -h <float>      high load mark (1.25)
          -l <float>      low load mark (0.25)
          -n <copies>     number of children to fork (1)
          -u <filename>   file that will be used to externally control a
                          loadwatch process.
          -p <pid>        pid of process to control (loadwatch will actually
                            send signals to the group containing this pid)
          NOTE: -p and <command> are mutually exclusive, but one has to be
                  specified.

Bob

P.S. And of course I am aware of $! for getting the pid.