https://bugs.freedesktop.org/show_bug.cgi?id=34377

Summary: Radeon driver PCIe throughput not up to PCIe2.0 levels Product: Mesa Version: git Platform: x86 (IA32) OS/Version: Linux (All) Status: NEW Severity: normal Priority: medium Component: Drivers/DRI/R600 AssignedTo: dri-devel@lists.freedesktop.org ReportedBy: lucvermoesen@gmail.com

Created an attachment (id=43476) --> (https://bugs.freedesktop.org/attachment.cgi?id=43476) test data and test program for PCIe gen2 issue

On an HD5450 card, when I load the latest gallium3D driver with kernel 2.6.38-rc4 and firmware I got from http://people.freedesktop.org/~agd5f/radeon_ucode/ , this together with the latest git checkouts for X and modules (and thus also xf86-video-ati) and latest mesa git checkout that has been built with –enable-gallium-r600

installing the radeon kernel module with modprobe radeon modeset=1 pcie_gen2=1

Then I get 0.5GB/s CPU->GPU

From GPU -> CPU, I get about the same 0.5GB/s.

When I load the fglrx ati proprietary driver (11.1) for the 5450 card, then I get throughputs of about 2GB/s in both directions.

Running the same test in same environment on the HD5970 with the gallium drivers and kernel mode setting and pcie_gen2 activation, i get about the same figures as above. With fglrx for 5970, then 5970 only performs well in CPU->GPU with about 2GB/s and only 0.5GB/s in GPU->CPU direction

I have included the test and configuration output for both cases (fglrx and radeon) and also code for the testprogram might you want to reproduce this case.