Re: [Xenomai] xenomai cyclictest negative Max value

[Peng Fan <van.freenix@gmail.com>]

On Wed, Dec 20, 2017 at 11:07:18AM +0100, Philippe Gerum wrote:
>On 12/20/2017 07:49 AM, Peng Fan wrote:
>> On Mon, Dec 18, 2017 at 10:26:28AM +0800, Peng Fan wrote:
>>> Hi All,
>>>
>>> I compiled xenomai-next on my ARM64 platform, but met Max and Avg not correct.
>>> See below:
>>>
>>> ./cyclictest -a -t10 -n -p99 -c 0
>>> # /dev/cpu_dma_latency set to 0us
>>> policy: fifo: loadavg: 0.97 0.51 0.21 1/135 3018
>>> policy: fifo: loadavg: 1.00 0.76 0.38 1/128 3018
>>> T:[  200.650323] random: crng init done      0 Act:    0 Avg:443149053456561 Max:      -1
>>> T: 0 ( 3002) P:99 I:1000 C: 373066 Min:      0 Act:    0 Avg:395570629834068 Max:      -11
>>> T: 1 ( 3003) P:99 I:1500 C: 248710 Min:      0 Act:    0 Avg:148339383810136 Max:      -111
>>> T: 2 ( 3004) P:99 I:2000 C: 186532 Min:      0 Act:    0 Avg:593359125738518 Max:      -1
>>> T: 3 ( 3005) P:99 I:2500 C: 149359 Min:      0 Act:    0 Avg:123506076458128 Max:      -11
>>> T: 4 ( 3006) P:99 I:3000 C: 124465 Min:      0 Act:    0 Avg:592833136181562 Max:      -1
>>> T: 5 ( 3007) P:99 I:3500 C: 106684 Min:      0 Act:    0 Avg:172910127795260 Max:      -111
>>> T: 6 ( 3008) P:99 I:4000 C:  93349 Min:      0 Act:    0 Avg:1383273613171719 Max:      -1
>>> T: 7 ( 3009) P:99 I:4500 C:  82977 Min:      0 Act:    0 Avg:666934598998863 Max:      -1
>>> T: 8 ( 3010) P:99 I:5000 C:  74679 Min:      0 Act:    0 Avg:988055226969271 Max:      -11
>>>
>>> Seems xenomai cyclictest and rt-tests cyclictest is not sync, or there are
>>> some differecense. Could you please help me clarify what's the difference
>>> between xenomai cyclictest and rt-tests cyclictest?  I did not find out which
>>> exact commit number when importing rt-tests cyclictest to xenomai.
>> 
>> I add a debug info in cyclictest.c, see below:
>> 
>> diff --git a/demo/posix/cyclictest/cyclictest.c b/demo/posix/cyclictest/cyclictest.c
>> index 31d9e5d0b..b16321cd9 100644
>> --- a/demo/posix/cyclictest/cyclictest.c
>> +++ b/demo/posix/cyclictest/cyclictest.c
>> @@ -920,6 +920,11 @@ void *timerthread(void *param)
>>                         diff = calcdiff_ns(now, next);
>>                 else
>>                         diff = calcdiff(now, next);
>> +
>> +               if (diff == -1) {
>> +                       printf("==== %ld %ld %ld %ld\n", now.tv_sec, now.tv_nsec, next.tv_sec, next.tv_nsec);
>> +                       exit(0);
>> +               }
>>                 if (diff < stat->min)
>>                         stat->min = diff;
>>                 if (diff > stat->max) {
>> 
>> And I encounter the case that diff is -1,
>> "==== 16124 21743627 16124 21744638"
>> only 1ns difference between now and next.
>> This means clock_nanosleep wakeup earlier than expected?
>> I am using 4.9.51 kernel, and xenomai-next on ARM64. I am tracking
>> the hrtimer things, but no good progress. Please advise, if you any ideas.
>> 
>
>You need to calibrate the core timer with the "autotune" utility. Some
>details available here:
>
>https://xenomai.org/documentation/xenomai-3/html/man1/autotune/index.html

I tried directly run "#autotune". It could fix the negative issue on i.mx6q and
i.mx7d. But on i.MX8 ARM64, I still could met the issue. Is there something
more that I could try?

Thanks,
Peng.

>
>-- 
>Philippe.

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