21 Jun 2012 15:49
22 Jun 2012 11:26
Re: OMAP4430 /Pandaboard using RT_PREEMPT - Experience?
I successfully booted a PB ES with a 3.2-something-rt kernel a while ago. I haven't tested much and I don't have pretty numbers to show out, but the board itself seemed to be stable.
I guess I used the latest 3.2 and latest available rt patch at that time. I still have a 3.2.18-rt29 patch in my download directory, so I guess this was around that time. When building my image, I used the vanilla kernel + the rt patch + the wlan patch (http://elinux.org/images/8/8d/0001a-omap4-pandaboard-wlan-fix.patch).
The image successfully booted on my Pandabaord ES and on a friend's Pandaboard. I guess that more recent kernels (with more recent RT patches) also boots, as there is a very limited activity on the RT patch itself - and recent kernels seems to boot quite easily on any Pandaboard. I will probably check 3.4 + rt in the coming weeks.
Best regards,
-- Emmanuel
On Thursday, June 21, 2012 3:49:56 PM UTC+2, Holger Adams wrote:
On Thursday, June 21, 2012 3:49:56 PM UTC+2, Holger Adams wrote:
Hello Everybody,
is somebody using the OMAP4430 with RT_PREEMPT and is willing to tell us
about their experience regarding worst case latencies, stability issues,
kernel/patch versions?
Thanks!
Holger
28 Jun 2012 15:35
Re: OMAP4430 /Pandaboard using RT_PREEMPT - Experience?
Hello Emmanuel, Am Fri, 22 Jun 2012 02:26:53 -0700 schrieb Emmanuel Deloget: > The image successfully booted on my Pandabaord ES and on a friend's > Pandaboard. I guess that more recent kernels (with more recent RT > patches) also boots, as there is a very limited activity on the RT patch > itself - and recent kernels seems to boot quite easily on any > Pandaboard. I will probably check 3.4 + rt in the coming weeks. Thanks for you informations! I tried following setup: - Kernel: 3.4.4 - RT-Patch: 3.4.4-rt13 # uname -a Linux pdev 3.4.4-rt13 #1 SMP PREEMPT RT Thu Jun 28 11:34:25 CEST 2012 armv7l armv7l armv7l GNU/Linux # cyclictest -t1 -p 80 -i 500 -l 10000000000 policy: fifo: loadavg: 64.78 68.71 68.55 3/214 4153 Min: 52 Act: 84 Avg: 85 Max: 5014 (around 7656995 cycles under heavy CPU and I/O-Load. Burnt my fingers touching the chip) The worst case jitter increases about 5000uS if I start write/read operations onto the SD-Card. Is this phenomena known out there? I disabled all powersaving settings in the kernel, also the the high precision timer (not this 32KHz thing) is being used. Best Regards, Holger
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