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Re: Windows users! Help us test upload performance tuning?

From: Daniel Jeliński <>
Date: Sat, 4 Aug 2018 19:40:01 +0200

2018-08-04 18:14 GMT+02:00 Jan Ehrhardt <>:
> curl was consistently a little bit faster than bash/lftp, but that may be
> related to the sftp encryption (curl ran plain ftp, port 21).
> curl vanilla and curl patched did not seem to differ. Sometimes patched was
> faster than vanilla, sometimes the other way around.
> @Daniel Jelinski: could you compile a version with sftp support?

I haven't figured out yet how to build libssh2, and I don't need it at
the moment.

Out of curiosity, I run some tests of SFTP using curl binaries by
Viktor Szakats [1] and some ancient CopSSH server. Uploads to
localhost were capped at ~300 KB/s. WinSCP was able to upload to the
same server at a rate of 4MB/s, maxing out one entire CPU in the
process (server used about 15% of another one), so Curl seems a little
unimpressive here.

On linux Curl uploaded to localhost (OpenSSH + sftp) at a rate of 15
MB/s, using 60% of a single CPU (server used ~30% of another one).
Tried both libssh and libssh2, didn't notice a difference. This result
is much better, but there may still be some room for improvement.

Received on 2018-08-04