tech-net archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: NetBSD 5.1 TCP performance issue (lots of ACK)

The speed

  with glusterfs: seems to be a combination of 74 MB/s and pauses

  with ttcp: seems to be 112 MB/s burst (for 0.2s) and some smaller
  pauses, which gut checks with 95 MB/s as reported by ttcp.

So are you seeing high 40s MB/s out of glusterfs?

What is between these two devices?  Is this just a gigabit switch, or
anything more complicated?  We are seeing reordering which I would not
expect on an ethernet.  I wonder if the tso4 option is causing that.
What if you turn off the offload options?  (I realize it may slow down,
but if both are then equal, that's a clue.)

I wonder if the very large buffers get full and that causes cache
thrashing.  What happens if you change gluster to have smaller buffers
(I don't understand why it's ok to have the FS change the tcp socket
buffer options from system default)?


to look at the plots yourself (you'll need xplot, but the conversion
From tcdpump is done already).

Attachment: pgp5bX2Ekzz3I.pgp
Description: PGP signature

Home | Main Index | Thread Index | Old Index