Re: [Bug-wget] GSoC15: Speed up Wget's Download Mechanism

[Ángel González]

On 29/04/15 10:02, Hubert Tarasiuk wrote:
> Hello developers,

> There are two tasks to be done there:

> - TCP Fast Open (RFC7413)
I didn't know about TFO. https://lwn.net/Articles/508865/ was a nice read!

> A summarized version of my proposal is available:
> http://pliki.h.trsk.org/gsoc/wget_public.pdf
>
> IMHO it is quite obvious how the first feature should be implemented in
> Wget. However, there is some more moving around needed to use TFO. I
> have proposed two possible ways in the above PDF. Perhaps you can
> express your opinion about the approaches, or you have another idea for
> accomplishing it?
So you are asking us about using sendto vs sendmsg? I don't know if the 
kernel
supports this as a TFO knob*, but using TCP_CORK (as suggested in the lwn
comments) would be a much saner way (with benefits with non-TFO 
machines, too).

* it makes sense that setsockopt(TCP_FASTOPEN|TCP_CORK) did this.


> Another issue I am thinking about is how to test the TFO feature. I am
> not very familiar with network API in Python, but my first idea would be
> to count the TCP segments sent and received and/or to check that the
> first packet (with SYN flag) contains data (the request). What do you think?
This is very hard. If you have a remote server supporting TFO and, you 
can easily
verify if it's being used with a network sniffer. But I don't expect the 
check
to be easy to automate. Specially for localhost.