[vlc-devel] [PATCH 0/1] Improve SFTP network performance with buffer

[Rémi Denis-Courmont]

Le perjantaina 2. maaliskuuta 2018, 21.42.22 EET Martin Disch a écrit :
> I worked around it by adding the error to the check you're already
> doing for the EAGAIN error, which did the job. I didn't do any
> elaborate measurements, but just looking at the bandwidth usage I
> didn't see an improvement. I was using a large prefetch buffer again,
> hoping to see the prefetch module fill it up quickly using all
> available bandwidth, but unlike when using a large read size, it
> didn't manage. It barely used enough bandwidth to keep up with
> playback and couldn't really prefetch anything.

AFAICT, SFTP does not block nor pipeline properly. CIFS has the same 
problem(1) and same potential solutions. One solution is to increase the read 
size in prefetch (or remove that totally and use the free buffer space).

The other option is to set fast-seekable since random access is as fast as 
linear access for those plug-ins. This will bypass prefetch and return to the 
VLC 2.2.x behaviour.

Either way, this will break support for low bandwidth. Since we cannot know 
upfront what the bandwidth is, it seems intractable.

(1) https://trac.videolan.org/vlc/ticket/19988#comment:17

-- 
雷米‧德尼-库尔蒙
https://www.remlab.net/