2 Replies Latest reply on Dec 30, 2011 12:22 AM by dschaa

    Maximum Work Group Size

    dschaa

      Currently we're using the environment variable GPU_MAX_WORKGROUP_SIZE to get around the 256 work item limit per work group.  I understand that there are performance implications for requiring too many work items to be active on a compute unit at a time, however, is there any chance of execution failure or incorrect computation?  We'd like the work group size to be up to 768. 

      Thanks!

        • Maximum Work Group Size
          d.a.a.

          Why don't you just increase the granularity of each work-item, so each one would process three elements (768/256) instead of only one?

            • Maximum Work Group Size
              dschaa

               

              Originally posted by: d.a.a. Why don't you just increase the granularity of each work-item, so each one would process three elements (768/256) instead of only one?

               

              Thanks for the reply.  I'm interested in this question in general, regardless if it's possible for a work item to process multiple elements.  Also, the code would become much more complex.  We have a bunch of different kernels that require greater than 256 work items, and multiple conditionals would be required for some of the kernels to ensure correct execution.