[PATCH] D52434: [OpenMP] Make default distribute schedule for NVPTX target regions in SPMD mode achieve coalescing

Gheorghe-Teodor Bercea via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Fri Sep 28 10:36:28 PDT 2018


gtbercea added a comment.

In https://reviews.llvm.org/D52434#1249186, @Hahnfeld wrote:

> In https://reviews.llvm.org/D52434#1249102, @gtbercea wrote:
>
> > You report a slow down which I am not able to reproduce actually. Do you use any additional clauses not present in your previous post?
>
>
> No, only `dist_schedule(static)` which is faster. Tested on a `Tesla P100` with today's trunk version:
>
> | `#pragma omp target teams distribute parallel for` (new defaults)         | 190 - 250 GB/s |
> | adding clauses for old defaults: `schedule(static) dist_schedule(static)` | 30 - 50 GB/s   |
> | same directive with only `dist_schedule(static)` added (fewer registers)  | 320 - 400 GB/s |
> |


Which loop size you're using ? What runtime does nvprof report for these kernels?


Repository:
  rC Clang

https://reviews.llvm.org/D52434





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