[Mesa-dev] [PATCH] mesa: skip FLUSH_VERTICES() if no samplers were changed

[Timothy Arceri]

On 24/06/17 11:45, Ian Romanick wrote:
> On 06/22/2017 03:56 PM, Timothy Arceri wrote:
>> ---
>>   src/mesa/main/uniform_query.cpp | 7 ++++++-
>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/mesa/main/uniform_query.cpp b/src/mesa/main/uniform_query.cpp
>> index 1570770..9683fa8 100644
>> --- a/src/mesa/main/uniform_query.cpp
>> +++ b/src/mesa/main/uniform_query.cpp
>> @@ -1071,21 +1071,26 @@ _mesa_uniform(GLint location, GLsizei count, const GLvoid *values,
>>       *     element that exceeds the highest array element index used, as
>>       *     reported by GetActiveUniform, will be ignored by the GL."
>>       *
>>       * Clamp 'count' to a valid value.  Note that for non-arrays a count > 1
>>       * will have already generated an error.
>>       */
>>      if (uni->array_elements != 0) {
>>         count = MIN2(count, (int) (uni->array_elements - offset));
>>      }
>>   
>> -   _mesa_flush_vertices_for_uniforms(ctx, uni);
>> +   /* We check samplers for changes and flush if needed in the sampler
>> +    * handling code further down, so just skip them here.
>> +    */
>> +   if (!uni->type->is_sampler()) {
>> +       _mesa_flush_vertices_for_uniforms(ctx, uni);
>> +   }
> 
> Do you have a test case where this helps performance (in a measurable
> way)?  If so, I may have a branch for you to try.

No. It's just something I noticed that made sense to do. The 
drawoverhead perf test [1] could likely be modified reasonably easily to 
test this.

What is the branch?

[1] https://cgit.freedesktop.org/piglit/tree/tests/perf/drawoverhead.c

> 
>>   
>>      /* Store the data in the "actual type" backing storage for the uniform.
>>       */
>>      if (!uni->type->is_boolean() && !uni->is_bindless) {
>>         memcpy(&uni->storage[size_mul * components * offset], values,
>>                sizeof(uni->storage[0]) * components * count * size_mul);
>>      } else if (uni->is_bindless) {
>>         const union gl_constant_value *src =
>>            (const union gl_constant_value *) values;
>>         GLuint64 *dst = (GLuint64 *)&uni->storage[components * offset].i;
>>
>