Re: Raspberry Pi 3B and pitiful network speeds

From: Denis Ovsienko <denis_at_ovsienko.info>
Date: Sun, 20 Jun 2021 15:41:05 +0100
On Sun, 20 Jun 2021 09:48:35 -0400
Karl Denninger <karl_at_denninger.net> wrote:

> > In case you need another reference point, my RPI3B (revision A22082)
> > sustains at about 50Mbit/s downloading from LAN over SFTP when it
> > runs NetBSD 9.2.  
> 
> The Pi2 and 3 both run Ethernet through the USB controller, which 
> significantly impacts performance.  IMHO it simply isn't capable of 
> being a high-performance network device due to architectural
> considerations.

I have just looked at the SFTP test closer. It looks like the
bottleneck is not network, but something related to CPU and filesystem
access: plain TCP download sustains at 100Mb/s (12.5MB/s) when done by
nc reading from /dev/zero at my PC and writing to /dev/null at the
RPI3B. The LAN between the two ends is a hardware switch plus a Linux
bridge plus an OpenBSD bridge (FreeBSD/RPI is also a good part of this
setup, but I am not ready to test it on the RPI3B right now).

Notwithstanding your point, under right conditions NetBSD 9.2 can fully
utilize the RPI3B's 100Mbit/s Ethernet interface, at least in one
direction at a time. Hopefully that means it should be possible in
FreeBSD too.

-- 
    Denis Ovsienko
Received on Sun Jun 20 2021 - 14:41:05 UTC

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