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Re: Re: FTP upload speed problem and buffer size

From: Daniel Stenberg <>
Date: Wed, 10 Oct 2007 18:58:04 +0200 (CEST)

On Wed, 10 Oct 2007, Ivan Makale wrote:

> I tried with various options you mentioned and other, without performance
> improvement. The problem is not the connection time but the transmission
> time. Just to give an idea:
> - with command line FTP about 500 kbytes/sec
> - with curl about 70 kbytes/sec

That's a so amazingly big difference so I fail to see how anything like a
modified window size or other minor tweaks would have this huge impact. I
would rather suspect a more major problem in the socket API for windows, or
something like that. The code doing transfers are basically the exact same on
all platforms.

> Forcing the buffer size of command line FTP to the same of curl (thas
> is, I suppose, 16384 bytes), with "ftp -w 16384 ..."

Are those really the same buffers we're talking about?

> I get about 250 kbytes/sec, again significantly faster than curl. Active or
> passive FTP doesn't change the speed. O.S.: Windows 2003 Server. I tried
> both with curl 7.15.1 and 7.17.0.

Are you using binary builds provided by someone or are you building your own?

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Received on 2007-10-10