Hi,
I'm trying to use the xeno_timerbench as a replacement to the old 2.0
klatency module and I encounter some problems.
This is on my in-progress ARM Xenomai port. User space latency and old
klatency work great (my board has some hardware latency problems though
- latencies can be as high as 500 us..). This in on a 2.6.14.5 kernel
using the latest ipipe patch and the latest SVN trunk xenomai.
Note that I never used the RTDM skin until now, so the problem could be
as well in the core RTDM code.
1) When compiled statically into the kernel, it does not work at all:
# /usr/xenomai/testsuite/latency/latency -p 10000 -t 1
== Sampling period: 10000 us
== Test mode: in-kernel periodic task
latency: failed to open benchmark device, code -19
(modprobe xeno_timerbench?)
2) When loaded as a module, it does work in -t 2 mode (kernel timer
handler):
# /usr/xenomai/testsuite/latency/latency -p 10000 -t 2
== Sampling period: 10000 us
== Test mode: in-kernel timer handler
warming up...
RTT| 00:00:01 (in-kernel timer handler, 10000 us period)
RTH|-----lat min|-----lat avg|-----lat max|-overrun|----lat best|---lat
worst
RTD| 6000| 14640| 72000| 0| 6000|
72000
RTD| 7000| 15060| 65000| 0| 6000|
72000
RTD| 7000| 15470| 72000| 0| 6000|
72000
---|------------|------------|------------|--------|-------------------------
RTS| 6000| 15056| 72000| 0|
00:00:03/00:00:03
But in -t 1 mode (kernel periodic task) it hangs hard just after the warming
period:
# /usr/xenomai/testsuite/latency/latency -p 10000 -t 1
== Sampling period: 10000 us
== Test mode: in-kernel periodic task
warming up...
Before hanging, sometimes it just prints:
Unable to handle kernel NULL pointer dereference at virtual address
0000004d
Sometimes the oops is more complete (note that sometimes it also hangs in the
middle of
the printout):
Unable to handle kernel NULL pointer dereference at virtual address
0000004d
pgd = c0004000
[0000004d] *pgd=00000000
Internal error: Oops: 817 [#1]
Modules linked in: xeno_timerbench
CPU: 0
PC is at xnpod_schedule+0x6b4/0x7f0
LR is at xnpod_schedule+0x54c/0x7f0
pc : [<c0056cc4>] lr : [<c0056b5c>] Not tainted
sp : c7d41830 ip : c79e8044 fp : c7d41860
r10: c0283c2c r9 : c0282
Does this rings a bell to someone ?
Thanks.
Stelian.
--
Stelian Pop <[EMAIL PROTECTED]>
