I currently experiment some problem with the Round Robin policy that
doesn't seem to work in V2.2.13 .
In RR each process should have the same time slice for its own
execution ie should have acces to the processor for (almost) the same
period of time. Thus each process should progress in the same way
(assuming that none of them is blocked on semaphores, queues...).
However this is not the behavior I got : it seems some process
monopolize the CPU almost untill their completion causing the other
processes to be starved
To illustrate this issue I made the following test:
I launched 10 times the same program with priority 10 of Round Robin
policy (from a shell having priority 20 of FIFO policy). Each program
does an infinite busy loop (while (1)).
One minute later, I launched the "ps" command and I was expected that
the TIME values of all these processes are in an interval which is T
large, where T is given by sched_rr_get_interval() i.e. T=150ms in
this release.
But the ps result was:
PID TTY TIME CMD
652 tty1 00:00:00 login
1549 tty1 00:00:00 bash
1566 tty1 00:00:00 bash
1596 tty1 00:01:12 my_program
1597 tty1 00:00:02 my_program
1598 tty1 00:00:01 my_program
1599 tty1 00:00:01 my_program
1600 tty1 00:00:05 my_program
1601 tty1 00:00:01 my_program
1602 tty1 00:00:00 my_program
1603 tty1 00:00:16 my_program
1604 tty1 00:00:01 my_program
1605 tty1 00:00:00 my_program
1610 tty1 00:00:00 ps
Does someone have any explanation of this behavior?
Thanks in advance.
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This archive was generated by hypermail 2b29 : Sat Jun 23 2001 - 21:00:20 EST