Taras, Thanks for pointing that out. The function looks good. Buffer autotuning was only introduced in curl 7.61, so the app using 7.57 will use the default (slow) buffer sizes. You shouldn't need to set UPLOAD_BUFFERSIZE to get good upload speeds on 7.65.1.
As for the connection timeout, it appears to be a well known problem with FTP on slow connections with oversized buffers. I just found a 10 year old message describing what looks like the same problem: https://curl.haxx.se/mail/archive-2009-08/0060.html I checked your upload_failure log, specifically the connection logged under T#12216. This connection appears to have ~100ms RTT, throughput ~5KB per RTT (50KB/s), for which the default 16KB buffer looks like overkill. In that environment sending the last ~700KB buffer would take about 15 seconds; curl timed out after 10. So yes, this problem was indeed caused by oversized UPLOAD_BUFFERSIZE. Back to slowness topic, can you reproduce the slow uploads using curl binary version 7.61 or newer? Regards, Daniel ------------------------------------------------------------------- Unsubscribe: https://cool.haxx.se/list/listinfo/curl-library Etiquette: https://curl.haxx.se/mail/etiquette.html
