timing errors

[email protected] Thu, 4 Jan 2007 10:32:00 +0200
Newsgroups gmane.linux.real-time.rtlinux.general
Message-ID <[email protected]>
Hello again,
I have ran the examples/measurement test and the results are not so
consistent as seen below.

ACPI and Power Management support was disabled from kernel. Test environment is:
rtlinux-3.2-pre3
prepatched-linux-2.4.29
pentium mobile 2 ghz cpu

absolute = 0;
mode = 0;
advance = 0;
bperiod = 0;

also commented negatif sign check of diff :
/*if (diff < 0) {
  diff = -diff;
}*/

Now starting the application
The "min" is the smallest timing error
A negative value means that the task ran too early
The "max" is the largest timing error
min:     -608, max:      768
min:     -192, max:      320
min:     -192, max:      224
min:     -192, max:      192
min:  -260480, max:   260608
min:     -192, max:      192
min:     -192, max:      192
min:     -160, max:      192
min:     -192, max:      224
min:     -320, max:      288
min:   -30176, max:    30112
min:     -192, max:      256
min:  -297280, max:   297184
min:     -160, max:      224
min:     -160, max:      192
min:     -192, max:      160
min:     -160, max:      128
min:     -192, max:      224
min:   -62368, max:    62496
min:     -192, max:      192
min:  -296320, max:   296320
min:     -192, max:      224
min:     -192, max:      224
min:     -192, max:      224
min:     -192, max:      160
min:     -192, max:      224
min:   -84992, max:    85056
min:     -192, max:      160
min:  -324576, max:   324736
min:     -160, max:      192
min:     -192, max:      224
min:     -192, max:      320
min:     -160, max:      224
min:     -192, max:      352
min:     -192, max:      192

Why so big values among them? I have tested same code on a platform
with pentium IV 2Ghz and results are not better but consistent.

Regards,

Deniz.
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