Login  Register

Re: Dual GPU 7990 card not using both GPUs concurrently

Posted by Wade Walker on Jul 03, 2015; 7:52pm
URL: https://forum.jogamp.org/Dual-GPU-7990-card-not-using-both-GPUs-concurrently-tp4034813p4034819.html

Sorry, that's what I get for reading too quickly -- didn't notice you were on AMD :)

Have you tried using clFlush() right after each clEnqueueNDRangeKernel()? This should ensure that the commands in the queues are actually issued to the devices before you call clWaitForEvents(). The docs are unclear, but it may be that clWaitForEvents() waits for events serially, performing an implicit clFlush() before each one, which would result in the serial execution you see.

I can't actually run this test, since I've only got one GPU. But if you're doing things like in JOCLMultiDeviceSample.java, the CL commands you're calling are just a thin wrapper around the C functions, so there shouldn't be any JOCL-specific weirdness going on.