[openib-general] Drop in performance on Mellanox MT25204 single port DDR HCA

[Hartman, Peter]

Adding:
Options ib_mthca tune_pci=1 

Puts MaxReadReq = 4096.

I get 1250MB/s bandwidth.


--  Peter

-----Original Message-----
From: Woodruff, Robert J 
Sent: Monday, October 02, 2006 3:51 PM
To: Roland Dreier; Hartman, Peter
Cc: Michael S. Tsirkin; openib-general; EWG; Hartman, Peter
Subject: RE: Drop in performance on Mellanox MT25204 single port DDR HCA

Roland wrote,
>However tune_pci=1 will make the driver override this setting if you
>really know what you're doing.

> - R.

Peter, can you give this a try ? 
I think you set this in /etc/modprobe.conf
add the line,
options mthca tune_pci=1

Also, we need to understand why the BIOS in your platform is setting it 
to 128 rather than 512. Is this an oversight in the BIOS or are they
doing it for a reason.

woody