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Re: Curl's network performance is slower than IDM.

From: Daniel Stenberg via curl-users <>
Date: Mon, 15 Jun 2020 23:44:15 +0200 (CEST)

On Sun, 14 Jun 2020, Hongyi Zhao via curl-users wrote:

> On Ubuntu 20.04

I presume that's curl 7.68.0 ?

> $ curl -L -x socks5h://
> >/dev/null
> % Total % Received % Xferd Average Speed Time Time Time Current
> Dload Upload Total Spent Left Speed
> 46 1024M 46 475M 0 0 9.7M 0 0:01:44 0:00:48 0:00:56 11.1M^C
> The IDM gives around 16 ~ 20 MB/s speed.

Are these transfer speeds somewhat stable and reliable in repeated tests?

Do the same symptoms reproduce even if you don't use a SOCKS proxy? What's the
theoretical maximum speed for you against this URL? From my dev machine in
Sweden, my curl reached 30MB/s from this URL.

> I'm confused on the above results. Why IDM shows a higher network
> performance than curl? Are there some bottlenecks/glitches/bugs in curl's
> network transfer algorithms?

I'm not aware of any. Reading on the IDM site, it seems very content about its
use of multiple connections and ranges to download data. Have you verified
that your test case with that actually only uses a single TCP stream? Just so
that we compare the same things.

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Received on 2020-06-15