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
http://rikalp.phy.bnl.gov/ccj/doc/NFSbench1.html
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
Condition
Client
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))
Server
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