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

[Marek Olšák]

On Wed, Jun 7, 2017 at 4:10 PM, Aaron Watry <awatry at gmail.com> wrote:
> On Mon, Jun 5, 2017 at 3:07 PM, Marek Olšák <maraeo at gmail.com> wrote:
>> Hi Aaron,
>>
>> Can you make the change in radeon_drm_winsys.c instead?
>
> Something like the following?
>
> diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
> b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
> index a485615ae4..44948f49ef 100644
> --- a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
> +++ b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
> @@ -365,6 +365,8 @@ static bool do_winsys_init(struct radeon_drm_winsys *ws)
>      /* Radeon allocates all buffers as contigous, which makes large allocations
>       * unlikely to succeed. */
>      ws->info.max_alloc_size = MAX2(ws->info.vram_size,
> ws->info.gart_size) * 0.7;
> +    if (ws->info.has_dedicated_vram)
> +        ws->info.max_alloc_size = MIN2(ws->info.vram_size * 0.7,
> ws->info.max_alloc_size);
>      if (ws->info.drm_minor < 40)
>          ws->info.max_alloc_size = MIN2(ws->info.max_alloc_size, 256*1024*1024);

Yes, feel free to push that.

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

Marek


>
> --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
>>>
>>> _______________________________________________
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>>> mesa-dev at lists.freedesktop.org
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