[HECnet] RSX FTP Performance Doubled!!

[Johnny Billquist]

Hi.

On 2019-08-28 13:32, Mark Matlock wrote:
> Johnny,
>      Congrats on the latest update to your TCP/IP package!!
> 
>      PROGRESS.DOC mentioned that FTP performance nearly doubles and I can confirm that is the case for me.
> 
>      I transferred you TCP/IP tape image from my 11/93 to a local PiDP-11 and saw the transfer rate over the course of the FTP transfer run 88.2 KB/sec!!
> 
>      A similar transfer in the past ran 40-45 KB/sec. I’d love to know what you did to double performance like that. I do have a M7516-YM DELQA-T in that 11/93 does that help?

Cool. I was testing on an 11/70, and depending on file, I could even see 
about 3x the performance.
It's actually about the work of reading the file in the first place. The 
"problem" is that FTP is using RMS. RMS have some very nice features 
which gives a fairly good performance. However, some files, RMS can only 
give block access to, and those were suffering from very slow 
performance, since FTP then read one block at a time, and sent it.
In comparison, for files RMS can deal with as records, RMS can do large 
blocks, and read ahead.

So what I now did was that I changed the block access code to run 
asynchronously, with large buffers, and with read ahead, which I 
implemented myself.

So there is actually nothing on the network side that caused this 
improvement, but just file access methods. And since my code is even a 
bit better than the RMS internal processing for known files, I also 
switched all access over to this method if the transfer happens between 
two RSX systems, or for block access mode.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol