Strange FTP upload speed regression

[tmcdos]

Hi

I observe something very strange on versions 8.x and 9.x
When I start Total Commander and try to upload some files on an FTP server the speed on average is 40 Mbit/s and sometimes even 50 Mbit/s. During the day (I keep Total Commander running all day) I often update files by FTP and there is a point in time after which my upload speed becomes 2 Mbit/s and does not change until I quit the TC and start it again. It does not matter if I reconnect to FTP after this point in time or whether it is passive vs. active FTP transfter - the only solution is to restart TC.

I am unable to determine if this happens after some fixed amount of time or it depends on the amount of uploaded files (or their cumulative size, or something else) - however, I observe this effect every single day.

I can provide an FTP account for testing but I am pretty sure the problem is in TC and not in the FTP server. And it takes some time to reveal itself - you won`t see it right from the start.

[ghisler(Author)]

You can try to set a fixed upload block size:
wcx_ftp.ini
[General]
UploadBlockSize=65536

It should be a 2^x value, e.g. 8192, 16384, 32768, 65536, 131072.

Why: TC starts with a small block size, and if the upload is fast, it gradually increases the block size.

[tmcdos]

Well, then I have a question - when the issue reveals, I immediately start another instance of TC (the current one remains active) and connect to the same FTP server and do the same file transfer - and the speed is the maximum possible for the network. If I switch back (e.g. by Alt+Tab) to the first instance of TC and again do the same FTP transfer - the speed is consistently 250 Kbytes/sec.

By the way, I am experiencing the issue in this very moment while I am posting this message.

[ghisler(Author)]

Hmm, no idea. Did you try my suggestion?

[tmcdos]

I do not want to make a premature conclusion, still watching.