3C905B-TX (nfs/netperf problem)

Takashi Ichihara ichihara@rikalp.phy.bnl.gov
Thu Jul 23 19:08:48 1998

   Thank you for all for many useful suggestions for my problem 
of 3C905B-TX interface operating at 100MBps.  Finally I found 
the reason of the problem and corrected it.
  At the booting time, the 3c59x.c V0.99E 5/12/98 device driver assumes 
that this interface is operating at 10BaseT mode by autoselect:

   Jul 20 14:17:27 p01 kernel:   8K byte-wide RAM 5:3 Rx:Tx split,
   autoselect/10baseT interface.

while this interface is indeed connected to CISCO 2916M Switch at 
100Mbps (CISCO Port LED shows that the connection is 100BaseTX)

  Since I do not know how to pass the option for this driver
under RH 5.1 Linux, I modify the  3c59x.c V0.99E  source code to 
give the initial value of option[1] as 4 (100BaseT) as follows

  static int options[8] = { 4, -1, -1, -1, -1, -1, -1, -1,};

Then at the booting time,

   Jul 22 16:50:41 p01 kernel:   8K byte-wide RAM 5:3 Rx:Tx split, 
   autoselect/NWay Autonegotiation interface.
   Jul 22 16:50:41 p01 kernel:   Media override to transceiver 
   type 4 (100baseTX).

This 3c59x.c V0.99E drivers recognized that this is a 100BaseT 
mode.  Then many problems have been fixed. Netperf shows 65 Mbps.
(Unfortunately,  option=20  i.e., full-duplex 100BaseT does not 
work well, it caused kernel panic, so I gave up using full-duplex 
mode and simply using 100BaseT mode)

   After this fix, the performance of the FTP (get) shows almost 
perfect.  Although NFS read is well (about 7-8MB/s) still NFS 
write seems to have performance problem (0.3-0.7MB/sec). Is this 
a limitation of the NFS V2.0 protocol ?

  Following shows a brief result of NFS/FTP preliminary performance 
measurements.  Detailed result can be found at

  Result Summary (file operation at Linux client)
   NFS Read 1 (disk to disk)       6.8  -  7.6   MB/s
   NFS Read 2 (disk to memory)     7.6  -  8.4   MB/s
   NFS Write  (disk to disk)       0.32 -  0.68  MB/s
   ftp get    (memory to memory)   9.2  - 10.6   MB/s
   ftp put    (memory to memory)   7.0  -  8.0   MB/s
   netperf                               65.36   Mbps


       Linux RH 5.1  Kernel 2.1.109, NFS V2.0   
       Hardware: Dual Pentium II at 400MHz, 256MB Memory (Dell Presision 410)
       3C905B-TX PCI Card (3C59x.c V0.99E option=4 (force 100BaseTX))

       Digital Unix 4.0D (500MHz Alpha, 320 MB Memory) 
       100BaseT Full Duplex, Seagate 9GB Ultra-wide disk

     Interconnection:  100BaseT Switch (CISCO 2916M)

				Thank you again. Best Regards,

					Takashi Ichihara