Menu

Tuning Advice

2021-07-03
2021-07-05
  • jason znack

    jason znack - 2021-07-03

    Hello, I'm trying to understand how best to tune the cache and buffer parameters for best performance.

    The setup is as follows

    1 server, and 6 clients on a gigabit network. All systems are pretty low end, but are running Windows 10 and have SSDs.

    Using version 5. No encryption. Unlimited rate.

    The data being sent is a couple larger 100mb or so sized files and a dozen smaller 1mb sized files.

    Jumbo frames are enabled on the network and all clients, so the block size is 8800.

    Using the defaults for cache and buffer the performance wasn't that great, raising them to the max was a bit better, but I'm not sure how best to tune it. I've been trying to find some guidance or examples or some logic behind it, but haven't found anything yet.

    Any help is appreciated. Thank you.

     
  • Dennis Bush

    Dennis Bush - 2021-07-04

    Jason,

    Try setting the block size to 8192, that way it's a multiple of the disk allocation size.

    Playing with the cache size should also have an effect. First try 2097152 (2MB) then go up in increments of 1048576 (1MB) to see how that changes the throughput.

    Regards,
    Dennis

     
  • jason znack

    jason znack - 2021-07-05

    How about the UDP buffer size? Leave as default?

    After playing with the cache it seems to be best around 3mb, and increasing the UDP buffer to 1500k seems to be better. I've applied the FastSendDatagramThreshold 1500 registry fix for windows.

    Preliminary results from today's testing:
    -c 2097152 -B 153600 = 90 sec
    -c 2097152 -B 768000 = 22 sec
    -c 2097152 -B 1536000 = 20 sec
    -c 2097152 -B 3072000 = 26 sec
    -c 3145728 -B 1536000 = 25 sec
    -c 10485760 -B 104857600 = 34 sec

     

    Last edit: jason znack 2021-07-05
  • Dennis Bush

    Dennis Bush - 2021-07-05

    I'd say go with at least 1MB (1048576) for the UDP buffer size. You can also adjust that up or down as needed.

     
    • jason znack

      jason znack - 2021-07-05

      Thanks. That jives with what I was able to see from some testing (Edited my post above with results)

      I'll do some further testing to fine tune.

       

Log in to post a comment.

Want the latest updates on software, tech news, and AI?
Get latest updates about software, tech news, and AI from SourceForge directly in your inbox once a month.