[Python-ideas] shutil zero-copy and exotic filesystems

Barry Scott barry at barrys-emacs.org
Tue May 29 13:17:46 EDT 2018

On Tuesday, 29 May 2018 16:42:13 BST Eric Fahlgren wrote:


> On our WAN, which has a VPN endpoint 3000 miles from our office, routing
> back to a test server another 2000 miles inside the network (tracert shows
> 12-15 hops, 200 ms latency, arrrg), copying is slow no matter what: we are
> lucky to see 40 Mbps on a connection that has the slowest link section at
> 100 Mbps.

This is a guess on my part, I may be way off base.
Maybe you are suffering from TCP windows scaling not work well enough?

This page claims there are bugs in the windows implementations.
Its also claimed, elsewhere, that some middle boxes mess up TCP windows 


Wikipedia has a good description of TCP windows scalling.


More information about the Python-ideas mailing list