Process

(system loading)

Process

(system loading)

Internals

Expected end = Start + Period

Sleep(Period)

Actual end = Current time

Latency* = Actual end - Expected end

Update per-thread statistics

Start = Current time

Loop

TimerThread

MainThread

Display statistics on the fly and/or in files

(min, max, avg, histogram of latency occurrences)

Time

Start

Expected end

Actual end

Period

Latency

(*) The latency includes the time to get the current time for “start” and “actual end” → -R option to check the clock resolution

Process

(system loading)

Systress is a conductor for the running tasks on the system (decides which process/thread run at any moment)