On 10/05/17 20:06, Samuel Pitoiset wrote:
On 05/10/2017 03:01 AM, Timothy Arceri wrote:
I made this same change a while back but found I couldn't really
measure any performance increase in practice. I suspect it's because
we already
limit the max loops with (1 << s) <= prog[i]->SamplersUsed and there
is generally no big gaps in used samples.
Did you manage to measure any improvement here?
No, I didn't but I don't think it will improve anything. Though it's a
common pratice to use a bit scan for bitfields, and it makes the code a
bit cleaner.
It does have potential to provide a small improvement as this is a
hotpath, hence the opt you are replacing. Anyway looks good so feel free
to add:
Reviewed-by: Timothy Arceri <tarc...@itsqueeze.com>
On 10/05/17 07:33, Samuel Pitoiset wrote:
The check in update_single_program_texture() can also be
removed.
Signed-off-by: Samuel Pitoiset <samuel.pitoi...@gmail.com>
---
src/mesa/main/texstate.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/src/mesa/main/texstate.c b/src/mesa/main/texstate.c
index 830b230b5d..c11a2e95fe 100644
--- a/src/mesa/main/texstate.c
+++ b/src/mesa/main/texstate.c
@@ -620,9 +620,6 @@ update_single_program_texture(struct gl_context
*ctx, struct gl_program *prog,
struct gl_sampler_object *sampler;
int unit;
- if (!(prog->SamplersUsed & (1 << s)))
- return NULL;
-
unit = prog->SamplerUnits[s];
texUnit = &ctx->Texture.Unit[unit];
@@ -676,16 +673,16 @@ update_program_texture_state(struct gl_context
*ctx, struct gl_program **prog,
int i;
for (i = 0; i < MESA_SHADER_STAGES; i++) {
+ GLbitfield mask;
int s;
if (!prog[i])
continue;
- /* We can't only do the shifting trick as the loop condition
because if
- * sampler 31 is active, the next iteration tries to shift by
32, which is
- * undefined.
- */
- for (s = 0; s < MAX_SAMPLERS && (1 << s) <=
prog[i]->SamplersUsed; s++) {
+ mask = prog[i]->SamplersUsed;
+
+ while (mask) {
+ const int s = u_bit_scan(&mask);
struct gl_texture_object *texObj;
texObj = update_single_program_texture(ctx, prog[i], s);
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