Re: [Owfs-developers] Simultaneous not working

[Mick S. <mi...@su...>]

No, just tested again and it now delays every 300 seconds.  Not the 
faintest idea why that should be.

I have a couple of I/O and a voltage sensor, so I will set it up again 
tomorrow with those in as well.

What do you use /presence for?  I have never used it before today.

Mick


On 06/08/2020 22:14, Martin Patzak wrote:
> I read the 25 powered sensors every 30 seconds and I don't experience 
> a delay every 120 seconds (my /presence is at default 120)
>
> I use /presence only when I get an error reading a sensor (happens 
> very rarely, but it happens)
> Then I wait until the sensor is present again before reading it. I use 
> the previous value instead.
>
> I also read 2 IO modules every second. Those are not affected by a 
> delay every 120 seconds either.
>
> Let's wait and hear what others say to that attribute.
>
> If you set it to 9999999 you experience no delays anymore?
>
> On 06.08.20 21:42, Mick Sulley wrote:
>>
>> I did change to persistent and I didn't see a difference.
>>
>> //settings/timeout/presence /is what is causing it.  I had tried 
>> changing it yesterday, via the httpd web page, but this time I 
>> checked it with owread and that showed it still at 120, so I changed 
>> it to 20 with owwrite re-ran my Python script and yes it slows every 
>> 20 seconds
>>
>> What is the purpose of //settings/timeout/presence/? The man page 
>> says 'Seconds until the /presence/ and bus location of a 1-wire 
>> device expires in the cache.', but I don't really understand what it 
>> does.  Surely the presence is confirmed by any read of the sensor.
>>
>> I have just tried setting it to -1, that is invalid, I thought it may 
>> disable it.  I set it to 0 and it is slow every time.  I have now set 
>> it to 9999999, not sure what the limit would be.
>>
>> Comments?
>>
>> Mick
>>
>> On 06/08/2020 16:48, Martin Patzak wrote:
>>> looks like you are getting close :-)
>>>
>>> I checked, and the only timeout of owserver that matches 120 is 
>>> //settings/timeout/presence
>>>
>>>
>>> /
>>> On 06.08.20 16:21, Mick Sulley wrote:
>>>>
>>>> Well this gets more curious.  I am now measuring the time for each 
>>>> read, reading type, power and latesttemp.  Time for all is 
>>>> generally < 0.1 seconds, but then when I hit the slow loop the read 
>>>> for type is around 0.7 seconds, the others still < 0.1 seconds.  I 
>>>> don't really need type so I removed it and re-tested, on slow loops 
>>>> the power read is around 0.7 seconds, latesttemp still < 0.1 
>>>> seconds.  So I removed power as well, just reading latesttemp, on 
>>>> slow loops that is now around 0.7 seconds. So it seems that at some 
>>>> point a sensor takes many times longer for its next read, 
>>>> irrespective of which field is read.
>>>>
>>>> I have now tested with 19, 11 and 2 sensors and the slow loop 
>>>> occurs every 120 seconds.  I am intrigued to know what causes this, 
>>>> any ideas?
>>>>
>>>> Thanks
>>>>
>>>> Mick
>>>>
>>>> On 06/08/2020 10:23, Mick Sulley wrote:
>>>>>
>>>>> OK I will log read times and see what that shows.
>>>>>
>>>>> You say 'I also log if the error of the 1wire bus changes.' how do 
>>>>> you do that?
>>>>>
>>>>> No I don't really need to read that fast, this is just a test 
>>>>> setup to get a better understanding so I can hopefully fine tune 
>>>>> my main system.
>>>>>
>>>>> There should not be anything else running.  I just tried running 
>>>>> top at the same time, I monitored it at the point of the slow scan 
>>>>> and didn't see anything else significant.
>>>>>
>>>>> Mick
>>>>>
>>>>> On 06/08/2020 09:06, Martin Patzak wrote:
>>>>>> It looks like your timing has improved after all!
>>>>>>
>>>>>> in your original Python-code you could time every read for each 
>>>>>> sensor.
>>>>>> I have also powered sensors and a read is usually faster than 0.1 
>>>>>> seconds.
>>>>>> I log in a file if the read took longer than 0.3 seconds, which 
>>>>>> is almost never the case.
>>>>>> I also log in the file if the whole reading loop took longer than 
>>>>>> 3 seconds, which again is almost never the case.
>>>>>>
>>>>>> I also log if the error of the 1wire bus changes.
>>>>>>
>>>>>> I read 25 sensors every full and every half minute, so maybe you 
>>>>>> could implement a delay as well and see if things get more 
>>>>>> consistent.
>>>>>> Do you need to read so fast in a loop for you application?
>>>>>>
>>>>>> What else is running on your machine? You could run top in 
>>>>>> parallel to your python loop.
>>>>>>
>>>>>>
>>>>>
>>>>>
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