Dear "Bigler, Stefan",
In message D839955AA28B9A42A61B9181506E27C4012E192F@SRVCHBER1212.ch.keymile.net you wrote:
This should give you raw serial driver performacne while a serial data transfer is running, while keeping functionality for all other use cases.
What do you think?
First we need to have a good and accepted solution to reduce the time in NetLoop e.g. read only the env when changed. Then the polling is not anymore critical path.
Hm... sorry, but I disagree. With my suggestion above, the time spent in NetLoop() does not matter any more at all. So no optimizations there will be needed to get your code working.
Optimizing NetLoop() is a complex thing with global impact that will require a lot of testing. There is little chance to see this in mainline soon - at least not in the upcoming 2008.12 release.
My suggestion however results in small code, and additionally this code affects only users of the new console multiplexing feature, but nobody else.
Such a modification could go into mainline much faster.
But I agree that it is a worthwile goal to optimize NetLoop() anyway.
The main problem from my point of view is the echo of the received data to serial and also to nc. This is done now immediately, character by character and this takes time (more than we have).
Sorry. I don't get it. It seems you bring up a new topic here.
Less than 6 hours before this you wrote: "The polling of the serial driver is too slow to get all characters. ... we added hooks to measure the time for tstc() execution. The measured time are: ... nc 15 Milliseconds".
My interpretation was (and is) that it's the *input* processing which is your major concern. And I showed a way to solve this problem ( at least I think that my suggestion will solve it).
Now you bring up a new topic - the time needed to output the characters. May be we should try and solve problems sequentially - if we throw all isses we see into one big pot we might not be able to swallow this.
BTW: did you measure any times for the character output?
Am I right when I say that between a read from character getc() until the next call of getc() we have 100 Microseconds to do all the required processing otherwise we lose data?
On average, yes. The time for a single character might be longer (up to close to 200 us) assumimg we are fast enough then to catch the third char. All this assuming a console baudrate of 115 kbps.
BTW - reducing the console baud rate would be a trivial way to avoid most of these issues ;-)
Best regards,
Wolfgang Denk