Latency traces I cannot interpret (sa1100, 2.6.15-rc7-rt1)

["kus Kusche Klaus" <kus@keba.com>]

I took some latency traces on our sa1100 (see attachment) running
2.6.15-rc7-rt1 with full preemption.
They look very bad at the first glance, but I cannot interpret them in
detail.

Trace 3, 4 and 5 seem to have obvious reasons: FPU emulation,
Framebuffer console updates, and compression/decompression of flash data
for jffs2.

Moreover, if I read these traces correctly, they just disable
preemption, but still allow interrupts. Is that correct? Can anything be
done against these latencies, i.e. do they really need to disable
preemption for such a long time?

However, traces 1, 2, 6 and 7 are completely mysterious to me.
Interrupts seem to be blocked for milliseconds, while nothing is going
on on the system? Moreover, there are console-related function names in
traces 6 and 7, although I've unconfigured the framebuffer console for
these runs!

Many thanks in advance for any help!

Klaus Kusche
Entwicklung Software - Steuerung
Software Development - Control

KEBA AG
A-4041 Linz
Gewerbepark Urfahr
Tel +43 / 732 / 7090-3120
Fax +43 / 732 / 7090-6301
E-Mail: kus@keba.com
www.keba.com

Attachment: traces.tar.bz2
Description: traces.tar.bz2