eriksl wrote:I didn't mean "poll your server subsecond", I meant that if you poll your server frequently (e.g. once every ten minutes) the precision will be quite acceptable, i.e. subsecond.
That's pretty much what I do and yes you can get down to a good precision. I do a lot of sleeping though so I have to poll a lot more than I normally would like. With the unit powered up all the time, the main clock is really quite good at keeping time and is only out about a second every day. If you correct every 30 mins as per the NTP best practice you can get millisecond time keeping.
eriksl wrote:In the meantime I have succeed in making the pbuf allocation from LWIP completely static, with minimal unnecessary overhead. End result is 5200 bytes to be thrown in and completely lost, but LWIP will never ask for more, at any point and it will be able to send and receive payloads of 4k over tcp and udp, not bad imho.
That will make the work on the LWIP (2) migration easier (less dependence on Espressif code). BTW I've left the code for mem_alloc/pvPortAlloc etc. stuff in, it's selectable using the lwip/opt.h file.
That's excellent! Can't wait to dig into that sometime soon.