curl / Mailing Lists / curl-library / Single Mail
Buy commercial curl support from WolfSSL. We help you work out your issues, debug your libcurl applications, use the API, port to new platforms, add new features and more. With a team lead by the curl founder himself.

Re: Epoll performance issues.

From: Tomalak Geret'kal via curl-library <curl-library_at_cool.haxx.se>
Date: Tue, 24 Nov 2020 17:32:20 +0000

On 23/11/2020 20:16, James Read via curl-library wrote:
> I have attempted to make two minimal codes that
> demonstrate my problem.
>
> The first can be
> downloaded from https://github.com/JamesRead5737/fast
> <https://github.com/JamesRead5737/fast>
> It basically recursively downloads http://www.google.com
> <http://www.google.com>, http://www.yahoo.com
> <http://www.yahoo.com> and http://www.bing.com
> <http://www.bing.com>
> I am able to achieve download speeds of up to 7Gbps with
> this simple program
>
> The second can be downloaded
> from https://github.com/JamesRead5737/slow
> <https://github.com/JamesRead5737/slow>
> The program extends the first program with an asynchronous
> DNS component and instead of recursively downloading the
> same URLs over and over again downloads from a list of
> URLs provided in the http001 file. Full instructions are
> in the README. What's troubling me is that this second
> version of the program only achieves average download
> speed of 16Mbps.
>
> I have no idea why this is happening. Shouldn't the second
> program run just as fast as the first?
>
> Any ideas what I'm doing wrong?

That's a lot of code you're asking us to debug.

Have you profiled it? Have you tried narrowing down the
problem to a smaller testcase? I find it hard to believe
that these are minimal.

Also, there is no recursion here.

Cheers

-------------------------------------------------------------------
Unsubscribe: https://cool.haxx.se/list/listinfo/curl-library
Etiquette: https://curl.se/mail/etiquette.html
Received on 2020-11-24