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Re: libssh2 optimization [was: Re: Windows users! Help us test upload performance tuning?]

From: Jan Ehrhardt via curl-library <>
Date: Sun, 26 Aug 2018 16:03:16 +0200

Daniel Jelinski via curl-library (Sun, 26 Aug 2018 09:09:58 +0200):
>added 100ms: original 310kB/sec, patched 9900kB/sec

Impressive results!

>The patched version is CPU-bound on lower latencies; when the latency
>goes higher, SSH window becomes the limiting factor. I read that HPN
>SSH should do better on high latency links, didn't try it out.

I had also been looking at HPN SSH. If you try that you should increase the
buffersize as well:

>It's not ready for inclusion; it requires cleanup, and breaks SSL
>backends other than openSSL with AES-CTR support.

There is an open issue with AES-CTR in HPN SSH:

I did not run any tests yet. I will see if I can build it for Windows under

Received on 2018-08-26