Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

Lee Revell
2004-10-30T19:52:23Z

On Sat, 2004-10-30 at 21:47 +0200, Florian Schmidt wrote:
> Hi, in the meantime i also booted into P9 again and the results differ
> dramatically. Much better in P9. Anyways, i reuploaded the tarball. The
> program tries to detect missed irq's now and counts the total number of
> irq's delivered by /dev/rtc. Since the program does not recover from missed
> irq's the "statistical" data for these runs is useless [except for the
> knowledge of the fact that one or more irq was missed :)]

Yup there is definitely something not right:

rlrevell@mindpipe:~/cvs/wakeup$ ./rt_wakeup 1024 100000
freq: 1024 #: 100000
setting up /dev/rtc.
locking memory...
turning irq on, beginning measurement (might take a while).
done.

total # of irqs: 100065. missed irq's: 4

mean cycle difference betweem two wakeups: 586332 cycles

min. cycle difference betweem two wakeups: 25184 cycles (#: 28766)
diff from mean diff: 561148

max. cycle difference betweem two wakeups: 2.78432e+07 cycles (#: 98195)
diff from mean diff: 2.72569e+07

mean difference from mean difference: 3759.45 cycles

You should modify the program to print something when it sees a big
miss. This would make it easier to figure out what kind of system
activity triggers the problem.

Lee