[Mesa-dev] [PATCH] radeonsi: don't use fast color clear for small images even on APUs

[Marek Olšák]

On Thu, Dec 28, 2017 at 12:29 PM, Konstantin Kharlamov
<Hi-Angel at yandex.ru> wrote:
> I'm wondering, how is r600g different in that regard? I tried wiring up the code into evergreen_do_fast_color_clear(), both in this state and by using 256*256 — however FPS for me always varies around the same 1420.
>
> That said, I'm seeing lots of CPU used by Xorg, glxgears, and compton — I'm wondering if CPU cap could be the reason?

r600g might benefit in the same way. glxgears requires the limit to be
at least 300*300.

Marek

>
> В письме от среда, 13 декабря 2017 г. 2:53:12 MSK пользователь Marek Olšák написал:
>> From: Marek Olšák <marek.olsak at amd.com>
>>
>> Increase the limit and handle non-square images better.
>>
>> This makes glxgears 20% faster on APUs, and a little more on dGPUs.
>> We all use and love glxgears.
>> ---
>>  src/gallium/drivers/radeonsi/si_clear.c | 9 ++++-----
>>  1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/src/gallium/drivers/radeonsi/si_clear.c b/src/gallium/drivers/radeonsi/si_clear.c
>> index 0ac83f4..464b9d7 100644
>> --- a/src/gallium/drivers/radeonsi/si_clear.c
>> +++ b/src/gallium/drivers/radeonsi/si_clear.c
>> @@ -418,26 +418,25 @@ static void si_do_fast_color_clear(struct si_context *sctx,
>>                           sctx->b.family == CHIP_STONEY)
>>                               tex->num_slow_clears++;
>>               }
>>
>>               bool need_decompress_pass = false;
>>
>>               /* Use a slow clear for small surfaces where the cost of
>>                * the eliminate pass can be higher than the benefit of fast
>>                * clear. The closed driver does this, but the numbers may differ.
>>                *
>> -              * Always use fast clear on APUs.
>> +              * This helps on both dGPUs and APUs, even small APUs like Mullins.
>>                */
>> -             bool too_small = sctx->screen->info.has_dedicated_vram &&
>> -                              tex->resource.b.b.nr_samples <= 1 &&
>> -                              tex->resource.b.b.width0 <= 256 &&
>> -                              tex->resource.b.b.height0 <= 256;
>> +             bool too_small = tex->resource.b.b.nr_samples <= 1 &&
>> +                              tex->resource.b.b.width0 *
>> +                              tex->resource.b.b.height0 <= 512 * 512;
>>
>>               /* Try to clear DCC first, otherwise try CMASK. */
>>               if (vi_dcc_enabled(tex, 0)) {
>>                       uint32_t reset_value;
>>                       bool clear_words_needed;
>>
>>                       if (sctx->screen->debug_flags & DBG(NO_DCC_CLEAR))
>>                               continue;
>>
>>                       /* This can only occur with MSAA. */
>>
>
>
>
>