HTTP POST only 550kbps throughput, too slow? Any tips on increasing performance?

[evtimmy]

Hi All,

I am trying to find what's the most performant way to have esp32 s3 upload jpg file (~500Kb) via HTTP post request to a server. It takes about 8 seconds at minimum, which comes out to about 550Kbps or 0.6Mbps. The file is already loaded in PSRAM, so I'm measuring only http post performance.

I've tried many settings and not much affects the speed.
- APIs I've tried: esp_http_client* APIs and Arduino HTTPClient (a little faster, but same ballpark).
- Menuconfig settings
-- WiFi IRAM speed optimizations enabled (not much difference).
-- Compiler settings - optimize speed
- Hardware
-- I've tried both external antenna as well as the built-in antenna - no difference. (I'm really close to the wifi router, just 3 meters).
- Server
-- I've tried both with and without TLS, minimal difference.

From what I'm reading, I should in theory be able to hit up to 20Mbps TCP traffic, but I'm stuck at 0.5Mbps.

Could you guys share what's your performance when uploading a single large file/buffer? Any tips on settings/things to check?