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

From: Daniel Stenberg via curl-library <>
Date: Sat, 18 Aug 2018 23:52:13 +0200 (CEST)

On Sat, 18 Aug 2018, Daniel Jeliński via curl-library wrote:

> I don't believe encryption is to blame here, at least not on curl side. I
> was able to upload 40 MB/s over https on plain 7.60 with 4MB socket buffer.

Encryption takes more CPU or hardware to get the job done so if you're CPU
bound and/or have huge bandwidth then encrypted transfers will of course be

With the same linux machine as I ran the previous tests, but this time against
an nginx on localhost:

- 7.61.0

$ time curl -sT 4GB -k https://localhost/sample.cgi


- 7.61.1-DEV (with 64KB upload buffer)

5.128s (780031201 bytes/sec)

Uploading over plain HTTP took 1.281 seconds with this buffer size (pretty
much exactly 4 times faster). But also, uploading to localhost means this test
both encrypts and decrypts on the same CPU.

As I showed before, if I upload HTTPS to my web site over a gigabit connection
I can saturate it; 100MB/sec. On a six years old desktop PC.


Received on 2018-08-18