My Speed Testing Results

[shane at home.infraredsolutions.com]

Hello all,

I've been looking at optimizing my performance (both throughput and CPU
wise) for Samba file sharing.  I have some rather interesting results...

My tests were done with a 1.9GB file on the server and a 1.8GB on the
client.  Here's the numbers:

Reading the 1.9GB file from the server, I could attain a peak of 7.1MB/sec
throughput, but it was on average closer to 6MB/sec.

Writing the 1.8MB to the server was another matter.  At one time I was able
to achive a 7.1MB/sec peak throughput as well, but the averages were quite
a bit lower, e.g 4MB/sec.  One interesting note here is that sometimes I
would only get around 2MB/sec.  

So here's the oddity.  In tweaking parameters and such, I was restarting
smbd between smb.conf changes for good measure.  My 4MB/sec write rate
would dramatically drop to 2MB/sec and I assumed it was from my parameter
change.  Undoing my parameter change and restarting still left me with a
2GB/sec write rate.  Strange...  Oddly enough if I restart smbd I will
occasionally get the 4MB/sec transfer rate, and other times get 2MB/sec.  I
can't figure out why it's different one time versus another.  I've tried it
with different client machines, same situation.  I've even had one work at
4MB/sec and the other at 2MB/sec...  It almost seems to me to be something
about the servers TCP/IP connection, but I really can't see how.

Specifically, I'm running RedHat 6.2 on a dual PPro 166/512K cache and I've
tried this with the included Samba 2.0.6 and my own compile of 2.0.7.  I've
also used the Stock Redhat Linux-2.2.14-XX kernel and the v2.4.0-test9
kernel.  Same effect on all variations.

So, despite my oddity, I have to say I'm quite impressed.  Transfering
directly between my client machines running Win98 (Celeron 550 and PIII
450) I didn't get nearly as nice of a transfer rate as w/ the server.  And
the clients always seem to use 100% CPU while the Samba server only uses
about 25-30% of the server CPU.  Very nice.

Ah, and my benchmark numbers were acquires using a network monitor from
AnalogX, so they aren't quite file MB/sec, but raw TCP/IP MB/sec (I think.)

Any ideas out there?  I'm going to keep trying to figure it out, it just
got too late last night for me to keep trying...

BTW: why aren't there any good 100MB network benchmarks out there?  All I
seem to find is some 10MB network benchmarks which aren't bad, but I'd like
to compare apples to apples...  (x86's to x86's?)

Cheers!

-= Shane.Anderson at infraredsolutions.com ======= 763-551-0003x229 =-
-= Sr. Electrical Engineer ==== http://www.infraredsolutions.com =-