esp-wifi/esp-mbedtls buffer sizes and location?

[yanshay]

I'm using esp-wifi with esp-mbedtls.
I need to supply both the sockets and the tls session buffers for tx/rx .
On top of that I need to supply buffers to put the read/write data (in my case I need to process around 10KB message).
And I'm short on memory so it's not simple.

1. Are there any specific requirements/guidelines for the size of the buffers for the sockets/tls? Can these be small even at cost of unoptimized communication (speed isn't a concern).
2. Is it safe to use PSRAM for those buffers?

[bjoernQ]

The mentioned buffers should be fine to live in PSRAM since they are only accessed by the CPU. Smaller buffers should be fine (with some performance penalty)

Since #2079 it's also possible to use some previously unavailable region in internal RAM as un-initialized memory (around 64k on most chips, even more on S2)

[yanshay]

Since #2079 it's also possible to use some previously unavailable region in internal RAM as un-initialized memory (around 64k on most chips, even more on S2)

I'm using esp32s3, In the past I encountered dram2 in ESP32, but I thought in ESPS3 it is no longer relevant, is it there as well? And isn't esp-wifi using that memory area (I remember that from quite some time ago, discussed here #1016)

[bjoernQ]

dram2 previously was only defined for ESP32 since there it is a "huge" chunk of memory. We now make the additional RAM available on all targets - on ESP32-S3 it's only as little as 64k but for applications which are already tight on memory that is a nice addition.

Recent changes on the main branch removed the internal esp-wifi heap in favor of using global heap for esp-wifi and other parts of the application (all of this is currently unreleased and only available on the main branch)