Hi all,
In the train today I'll be working on the serialization (Which will be a
challenge)
But I am sure this will be a lot of hard work but also a great step forward.
Is there any progress on the Driver-Logic generation front?
Otherwise I would probably try to whip up a hand-written Netty layer using the
generated model.
Without all the parser/serializer code this should only be a fragment of the
existing driver code.
Chris
Am 05.06.19, 09:59 schrieb "Strljic, Matthias Milan"
<matthias.strl...@isw.uni-stuttgart.de>:
Hura sounds nice 😉
I hope I find time to play a bit around with it in the next few days.
Greetings
Matthias Strljic, M.Sc.
Universität Stuttgart
Institut für Steuerungstechnik der Werkzeugmaschinen und
Fertigungseinrichtungen (ISW)
Seidenstraße 36
70174 Stuttgart
GERMANY
Tel: +49 711 685-84530
Fax: +49 711 685-74530
E-Mail: matthias.strl...@isw.uni-stuttgart.de
Web: http://www.isw.uni-stuttgart.de
-----Original Message-----
From: Christofer Dutz <christofer.d...@c-ware.de>
Sent: Tuesday, June 4, 2019 4:16 PM
To: dev@plc4x.apache.org
Subject: [CodeGen] Performance values
Hi all,
so as I mentioned in Slack yesterday I was able to successfully parse a S7
packet with the code generated by the code-generator.
There I am using Apache Jexl for evaluating the expressions we are using
all over the place. It got things working quite easily.
However my gut-feeling told me all these Jexl evaluators I’m creating can’t
be that ideal.
But not wanting to pre-maturely optimize something that’s already good, I
did a measurement:
So I did a little test, in which I let my parser parse one message 20000
times.
It came up with an average time of 0,8ms … this didn’t sound too bad
compared to the about 20ms of the interpreted daffodil approach.
But is this already good? It’s probably not ideal to compare some results
with the ones we know are bad, instead I wanted to compare it to the ones we
are proud of.
In order to find out I whipped up a little manual test with the existing S7
driver.
For this I simply plugged the 3 layers together with an Embedded channel
and used a custom handler at the end to return the message.
This seems to work quite nicely and I was able to run the same test with
the Netty based S7 driver layers we have been using for the last 2 years.
The results were:
Parsed 20000 packets in 796ms
That's 0.0398ms per packet
So this is a HUGE difference .
As one last check I ran JProfiler over the benchmark and it confirmed that
87% of the time was used by Jexl.
However the creation of Jexl expressions, not their evaluation.
So one optimization I’ll try is to do, is to have the expressions created
statically and then to simply reference them.
This will increase the complexity of the template, but should speed things
up.
And I’ll also change the code I’m generating for the Type-Switches to work
without jexl.
Simply assuming this would eliminate the time wasted by jexl (great
simplification), we would reduce the parse time to 0,1ms which is still about 3
times that of the existing driver.
I am assuming that this might be related to the BitInputStream I am using …
but we’ll deal with that as soon as we’re done with getting rid of the time
wasted by Jexl.
So far an update on the generated-drivers front.
Chris
