[Kst] kst 2.0 : No auto update?

Peter Milne Peter.Milne at d-tacq.com
Tue Aug 17 10:49:04 CEST 2010

On 08/17/2010 12:21 AM, Peter Kümmel wrote:
>> We'll get by with pressing the "Reload" button so long, I'll try the
>> threaded timer hack some time.
> Is it a solution to simply trigger a "Reload" automatically by a timer,
> without touching any 'watcher' code?

Yes. Simply pressing the button works OK, so a timer maybe would be 
better. Other than every so often the refresh is bad, maybe because Kst 
is reading data as it is being updated at the source. And there'd need 
to be a timer-disable button to stop reloading in the cases where the 
data is static.

I'm sure you're aware there are a few potential pitfalls in this area:

Doing a full Reload is of course forcing Kst to re-read all the data, 
that could end up causing a lot of network traffic, whereas a 
file-change-notify certainly only triggers on change, and, depending on 
how the file read logic is structured, maybe only the new data has to be 
read, rather than _all_ the data?. There's still the possibility of a 
data fetch clashing with a data put, but that may be lower since the two 
actions are now in sequence.

OTOH, how well does a notify scheme work in practice? - if there are 32 
data traces, they all advance by one sample, generating 32 separate 
file-change-notify events, then maybe a timed-reload actually works 
better?. I like file-per-channel in DirFile because it's really simple 
for clients to access the data, but this is one case where a single file 
with all the channels would probably work better..

Maybe the above worries are exaggerated, since the live plot of the 
SAMBA mounted data works well in Kst 1.8, seems like a good idea to do 
the same thing - with a cross-platform library to hide the OS 
differences :-).

Peter Milne			Peter.Milne at d-tacq.com
D-TACQ Solutions Ltd		www.d-tacq.com

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