Re: Wanted: Performance Analysis Tools on PCs Info

[vestal@SRC.Honeywell.COM (Steve Vestal)]

In article <1991May23.063331.13782@telesoft.com> rlk@telesoft.com (Bob Kitzberger @sation) writes:

Bob> Your next highest priority task should probably be the lowest frequency
Bob> task (if you are following Rate Monotonic Scheduling).  At each period
Bob> boundary, it can check the value of the global variables being updated
Bob> by the slack task.  If you know how quickly the slack task increases
Bob> these global counters when the system load is nil (nominal case), then you 
Bob> can calculate the amount of time spent in the slack task over the
Bob> measurement period.  100% minus the time spent in the slack task is your
Bob> system load.  Determination of the maximum rate at which the slack task can
Bob> update global counters is pretty straightforward, and only needs to be done
Bob> once.

I've done something similar to this, it works reasonably well.  I got fairly
close agreement between the measured utilizations etc. and analytically
predicted values (inputs to the analytic model were obtained via a "standard"
benchmark suite to measure various scheduling overheads).  There's a Tri-Ada
'90 paper about this.

Steve Vestal
Mail: Honeywell S&RC MN65-2100, 3660 Technology Drive, Minneapolis MN 55418 
Phone: (612) 782-7049                    Internet: vestal@src.honeywell.com