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[sectroyer]

How can I initialize multiple GPU's in order to use them with OpenCL on Linux?

Do I need to run multiple X11 instances?

Is it necessary to have multiple displays connected or is one (main/default) enouth?

[davibu]

Originally posted by: sectroyer How can I initialize multiple GPU's in order to use them with OpenCL on Linux?

Do I need to run multiple X11 instances?

Is it necessary to have multiple displays connected or is one (main/default) enouth?

Just run the following command and restart the Xserver:

sudo aticonfig --adapter=all  --initial -f

However, beaware, you have to install Catakyst 10.7 and OpenCL SDK 2.1.

SDK 2.2 requires Catalyst 10.7b but the support for multi-gpus in 10.7b is totally broken.

You have also to connect a monitor to each card: headless configuration is not supported (however there is some workaround you can find described in other thread in this forum).

[sectroyer]

I have tried similar solution with two 5970 and it failed Since this card has two outputs do I have to connect 4 displays if I have two 5970 or is it enouth to connnect two displays (one to every card)? BTW about which workaround you are talking? I have tried few and it didn't work

[davibu]

Originally posted by: sectroyer I have tried similar solution with two 5970 and it failed Since this card has two outputs do I have to connect 4 displays if I have two 5970 or is it enouth to connnect two displays (one to every card)? BTW about which workaround you are talking? I have tried few and it didn't work

First of all, I hope you are aware that 5970 is supported only as a single GPU by ATI OpenCL. You will be able to see only 2 OpenCL GPU devices out of your 4 GPUs.

I have a 5870+5850 connected to the same monitor (I'm using just 2 different input connectors of the same monitor). I don't have a 5970 so I don't know if it can be configured by connecting just one monitor.

You can find many posts with google about how to make dummy vga connectors to cheat the GPUs.

[HarryH]

google "vga dummy connector"

[sectroyer]

I have a system with two 5970 and  all connectors plugged (Catalyst center reports 4 displays connected) if I setup xorg conf using:

aticonfig --adapter=all  --initial -f

CLInfo reports only one GPU (first core of first 5970)

if I setup xorg using:

aticonfig --adapter=0  --initial -f

CLInfo repots two GPUs (first and second core of first 5970)

Since there is a problem with second cores of 5970 I've also tried seting up xorg using:

aticonfig --adapter=0,2  --initial -f

Nevertheless it doesn't help at all. After running startx I get black screen after few seconds system reboots I've tested it on few machines. Anyone knows how to make it work ?

[zeland]

What software do you use? SDK, driver versions, uname -a, linux Distributive.

and hardware of course mainly motherboard.

[davibu]

Try with:

export DISPLAY=:0

before to run CLinfo.

[sectroyer]

I have installed driver 10.7 (as suggested above) and tried with SDK versions 2.1 and 2.2.

I use CentOS 5.5

I don't believe it's a problem with motherboard since both cards work (I can see Desktop on both displays) and I was able to test both GPU's (on the same machine) under windoze.

Will exporting DISPLAY help with anything (I do not have an access to test machine at the moment) fi I was running all test's in terminal in gnome? I believe setting this variable is necessary if I am running OpenCL programs from "pure console" or SSH...

[nou]

normaly DISPLAY=:0.0 and you get acess only to one GPU. :0.1 is second :0.2 is  third etc. :0 is all devices.