GNIC-II (Hamachi) Performance

[Claude Lefrancois]

Hello !!!

I'm still playing with two GNIC-II cards. But this time, I have two
identical test platforms which are Dell Precision Workstation 410
computers:

	Dual Pentium II 450 MHz / 512 KB cache
	256 MB ECC RAM / 100 MHz
	Adaptec 2940 U2W SCSI controller
	9.0 GB Seagate Cheetah 10,000 RPM
	32x NEC SCSI CDROM
	Matrox Millenium G200
	3COM 3C905B Cyclone
	Packet engines GNIC-II

The machines are running RedHat 5.2.
	
The computers are linked to the company LAN via the Cyclones boards. I 
have a dedicated gigabit ethernet link between these two computers via 
the GNIC-II cards.

My main test is a simple ftp from one computer to the other one. The
file I use is a 120 MB binary file.

My main question is: How can I improve the performance of these cards 
?

>From the mailing list, I saw that the kernel version is one of the
factor that can improve the performance of the GNIC-II. The gigabit
ethernet performance is really better with the development kernels. I
now run 2.1.129 on both computers and I can reach 24 MB/s of transfer
rates while I had something like 12 MB/s with 2.0.35. Not bad.

Once again, from the mailing list, the MTU value seems to be another
factor that can improve the ethernet performance of the GNIC-II. I
have tried to change the MTU value at the module load time to 9000, 
8192, 4096 and 2048. At each time, I was able to initiate a ftp to the 
other machine but when I tried to transfer the file, I received
nothing. The received file size was always 0. Nothing was
transfered. So I had to come back to the standard MTU value. Is it
possible to change this value and have good transfers between the
computers ?

I also try to change the receive and transmit buffer values to 32, 64, 
128 and 256 with no effects. The transfer rates are always about 24
MB/s. How can I change these values to improve the performance of the
GNIC-II ?

I'm sure the GNIC-II cards can do better. The hardware is really up to 
date. I have the fastest SCSI disks, SCSI controllers, cpus, buses,
ram, etc. The only thing that I cannot improve is the 64bit PCI
slot. The Dell computers I have does not have 64 bit slots.

Do you think this card can do 80 MB/s ?

Thanks a lot for the help !!!

Claude Lefrancois.

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