From our observations we can tell that the error should not exceed 4%.
However, there is no reasonable explanation by now why the test results
are less stable on these platforms. We have tried several things that
did not lead to an explanation or improvement:
* changing the timing parameters of the scheduler
* switching off SMP
* double-checking the speed of userland and kernel timers
Ref #1805
The test threads previously used a stack size independent from the machine
word width. Qemu was previously configured to provide 64Mb of RAM which isn't
sufficient for x86_64.
Ref #1805
Print result error and error tolerance per test result. Use TCL commands
'format' and 'abs'to simplify calculations in the conclusion part of the run
script.
Ref #1805
The timer driver on X86 needs CPU quota with highest priority as it
frequently has to interrupt the counters to update the PIT.
On ARM this makes no difference in the test results as ARM timer
drivers, once configured, can sleep until the end of the timeouts.
On X86 we raise the error tolerance to 2% (default 1%) to compensate
the error caused by the timer.
Fixes#1621
Printing all errors and the goal values instead of exiting at the first
error allows for faster analysis of problems with the CPU-quota
mechanism.
Ref #1616
The test always succeeded because I forgot to set the error tolerance from
my debugging value 1 back to the correct value 0.01 before commiting the
test.
Ref #1616
Physical CPU quota was previously given to a thread on construction only
by directly specifying a percentage of the quota of the according CPU
session. Now, a new thread is given a weighting that can be any value.
The physical counter-value of such a weighting depends on the weightings
of the other threads at the CPU session. Thus, the physical quota of all
threads of a CPU session must be updated when a weighting is added or
removed. This is each time the session creates or destroys a thread.
This commit also adapts the "cpu_quota" test in base-hw accordingly.
Ref #1464
