On Fri, 2005-09-23 at 16:04 -0700, Darren Hart wrote:
> I am trying to run all the tests in the above tarball on a 2.6.13 kernel with
> ktimers+tod+hrt + a hrt compatibility patch which uses the normal clocks when a
> _HR clock is requested since ktimers treats them the same. I remember there
> used to be a run_tests script or something when this was a kernel patch, but I
do_test
> am not seeing that or any kind of documentation on how to interpret the output
> of the tests which output numbers rather than pass/fail. For instance:
>
> # ./1-4
> it value left is 3 999985323
> What does that even mean?
Cryptic POSIX compliance test output.
The test does the following:
Arm a timer with 2 seconds and a intervall of 5 seconds
(signal to deliver is SIGCONT).
Sleep for 3 seconds
Read the remaining time for the timer
The flow of events is
0 arm timer
sleep(3)
0+2sec timer expires and interupts the sleep.
The delivered signal is sigcont, so the sleep is resumed and sleeps the
full 3 seconds. Timer is rearmed with 5 secs.
0+3sec sleep returns
timer_gettime() is called to retrieve the time until the next expiry
of the timer, which should be ~4sec.
> Should I only be running executables that end in
> -test perhaps? Are some of these for use by the other tests?
do_test is the script running all the relevant tests AFAICT.
> # ./clock_nanosleep
> Clock resolution 1.000 usec
> Requested delay actual delay(sec) error(sec)
> 4.000001000 4.000015298 0.000014298
>
> Looks like clock_nanosleep has errors < 15 usecs, actually seems like a lot for
> a kernel built with 1us resolution (unloaded) - or does this test include some load?
No. Yoe see the following
t1 = gettime()
nanosleep()
timer is programmed
timer event interrupt happens
soft interrupt is invoked
soft interrupt wakes task
return from nanosleep
t2 = gettime()
delta = t2 - t1
So what you see is the overhead of syscalls, the possible interrupt
delay and the overhead of the softirq and the task switch / return to
userspace.
> # ./nanosleep_jitter
> Iteration iter time (secs) min sleep max sleep
> 0 0.051953 0.051952 0.000052 0.000052
> 1 0.051953 0.051952 0.000052 0.000052
> ...
>
> Is this what is expected? I believe the test intends to sleep for .05 seconds
> (50 milliseconds), I seem to be sleeping an extra 2 milliseconds. Seems like a
> lot actually.
The tests sleeps for 1000 x 50us = 50ms. So having a sleep of ~52usec
each time gives you the 52ms per test
> # ./sigevthread-test
> perror: Invalid argument
> timer_create failed.
>
> I gather is a conflict with the ktimer implementation?
I think not. It never worked for me. I ignored it as it is not part of
the do_test tests.
>
> # ./timerlimit
> 7168: timer id = 7167
> timer_create: Resource temporarily unavailable
>
> Is that a reasonable number of successfully created clocks?
Depends on the number of timers available on your system. But sounds
reasonable.
I have no idea about the plots. George ?
tglx
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