[Mesa-dev] [PATCH 2/2] RFC: radeon/compute: Limit allocations for VRAM-based chips to 3/4 VRAM

[Aaron Watry]

On Mon, Jun 5, 2017, 3:08 PM Marek Olšák <maraeo at gmail.com> wrote:

> Hi Aaron,
>
> Can you make the change in radeon_drm_winsys.c instead?
>

I'll give it a shot.

--Aaron


> Thanks,
> Marek
>
> On Mon, Jun 5, 2017 at 2:32 AM, Aaron Watry <awatry at gmail.com> wrote:
> > The CL CTS queries the max allocation size, and then attempts to
> > allocate buffers of that size. If any of the VRAM is in use, this
> > causes errors in the radeon kernel module.
> >
> > It's a bit of a hack, but experimentally on my system, I can use 3/4
> > of the card's VRAM for a single global/constant buffer allocation given
> > current GUI/compositor use.
> >
> > If there's a way to get the actual amount of free VRAM, I'd love to hear
> about it.
> >
> > Also, I'm unsure if the radeon kernel module requires all allocated
> memory to be
> > contiguous, if so, then we'd need to be able to get at that value.. I'm
> suspecting
> > that's not actually the case.
> >
> > For a 1GB Pitcairn (HD7850) this gets me from the reported clinfo values
> of:
> > Global memory size                              2143076352 (1.996GiB)
> > Max memory allocation                           1500153446 (1.397GiB)
> > Max constant buffer size                        1500153446 (1.397GiB)
> >
> > To:
> > Global memory size                              2143076352 (1.996GiB)
> > Max memory allocation                           805306368 (768MiB)
> > Max constant buffer size                        805306368 (768MiB)
> >
> > Fixes: OpenCL CTS test/conformance/api/min_max_mem_alloc_size,
> >        OpenCL CTS test/conformance/api/min_max_constant_buffer_size
> >
> > Signed-off-by: Aaron Watry <awatry at gmail.com>
> > ---
> >  src/gallium/drivers/radeon/r600_pipe_common.c | 17 +++++++++++++++--
> >  1 file changed, 15 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/gallium/drivers/radeon/r600_pipe_common.c
> b/src/gallium/drivers/radeon/r600_pipe_common.c
> > index 2c0cadb030..cdd4062fd3 100644
> > --- a/src/gallium/drivers/radeon/r600_pipe_common.c
> > +++ b/src/gallium/drivers/radeon/r600_pipe_common.c
> > @@ -1144,8 +1144,21 @@ static int r600_get_compute_param(struct
> pipe_screen *screen,
> >                 if (ret) {
> >                         uint64_t *max_mem_alloc_size = ret;
> >
> > -                       *max_mem_alloc_size =
> rscreen->info.max_alloc_size;
> > -               }
> > +                       uint64_t max_alloc =
> rscreen->info.max_alloc_size;
> > +
> > +                       if (rscreen->info.has_dedicated_vram) {
> > +                               /* XXX: Hack to prevent system hangs...
> > +                                * Limit to 3/4 VRAM for any single
> allocation.
> > +                                * Prevents:
> > +                                *     radeon: Not enough memory for
> command submission.
> > +                                */
> > +                               *max_mem_alloc_size = MIN2(
> > +                                       rscreen->info.vram_size * 3 / 4,
> max_alloc
> > +                               );
> > +                       } else {
> > +                               *max_mem_alloc_size = max_alloc;
> > +                       }
> > +        }
> >                 return sizeof(uint64_t);
> >
> >         case PIPE_COMPUTE_CAP_MAX_CLOCK_FREQUENCY:
> > --
> > 2.11.0
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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