andrzej zaborowski wrote: ...
In terms of bottlenecks I'm sure the muxer is not one, neither is the gsm module, if you want to use the usual serivces (GPRS/EDGE). I think Harald did post some numbers from his experience in A780 project where they actually have a working kernel-side TS0710 implementation (written in a very A780 centric way unfortunately) including bit rates at which the muxer potentially starts to be the bottleneck. Below that it's just some wasted cycles from going to userspace and back more than necessary.
The Linux serial driver is an abomination in itself (the only saving grace is that it's largely compatible back to the days of the ASR33 teletype machine). IMO, if performance is the goal, we need to consider a custom high-speed serial driver for the UART connected to the GSM, one that gets rid of the overhead of the entire tty layer in the kernel.
Mike (mwester)
