FW: Patch for slow smbclient performance

[Craig Bridge]

David Collier-Brown replied:

> 	Cool!
> 	In smbclient, this eventually changes the size of an fread on
> 	the socket...  anyone have an idea why reducing from 65520
> 	to 1200 would make a Poisonus Computer perform better?
> 
> --dave
> 
[Craig Bridge]  

Winsock client code splits large requests into smaller  packets.
Client "fairness" limits on how many outstanding packets
prolong the acknowledgement of the last packet leaving the
I/O request blocked.

Single threaded user mode code will ping-pong between
blocked on a large read and blocked on a large write.

Two user-mode threads (a reader and a writer) allow read-ahead
and socket transmission to overlap.  My experience is the
large negative "knee" in the performance curve is reduced and a
more monotonic perfomance curve is obtained.  Transfer sizes
near low multiples the underlying blocking factors will still show
up in the performance data.

-Craig