[Impeller] add benchmarks for the stroke geometry entity code

[flar]

Adds benchmarks (and backend support methods) for tracking the performance of the stroking code in the entity geometry package.

[flar]

Some notes:

• The same backend methods could be used to write some unit tests with another friend statement
• I only tested 2 axes of the 9 possible combinations of cap/join using the simplest cap with all joins and the simplest join with all caps
• RRect doesn't invoke any caps or joins so it is only run with token butt/bevel settings
• I'm not sure why the Round_Bevel and Square_Bevel results are nearly the same...?

[flar]

Sample output showing all of the combinations that are now run:

-------------------------------------------------------------------------------------------------------------
Benchmark                                                   Time             CPU   Iterations UserCounters...
-------------------------------------------------------------------------------------------------------------
BM_Polyline/cubic_polyline                               9478 ns         9471 ns        75427 SinglePointCount=155 TotalPointCount=11.6912M
BM_Polyline/cubic_polyline_tess                         34617 ns        34510 ns        20027 SinglePointCount=471 TotalPointCount=9.43272M
BM_StrokePolyline/stroke_Cubic_Butt_Bevel                4676 ns         4662 ns       149240 SinglePointCount=906 TotalPointCount=135.211M
BM_StrokePolyline/stroke_Cubic_Butt_Miter                5450 ns         5439 ns       131071 SinglePointCount=801 TotalPointCount=104.988M
BM_StrokePolyline/stroke_Cubic_Butt_Round               16685 ns        16653 ns        42292 SinglePointCount=946 TotalPointCount=40.0082M
BM_StrokePolyline/stroke_Cubic_Square_Bevel              4768 ns         4754 ns       147723 SinglePointCount=906 TotalPointCount=133.837M
BM_StrokePolyline/stroke_Cubic_Round_Bevel               4826 ns         4804 ns       146950 SinglePointCount=906 TotalPointCount=133.137M
BM_StrokePolyline/stroke_Cubic_Butt_Bevel_uv             9342 ns         9316 ns        75521 SinglePointCount=906 TotalPointCount=68.422M
BM_StrokePolyline/stroke_Cubic_Butt_Miter_uv             9104 ns         9064 ns        77211 SinglePointCount=801 TotalPointCount=61.846M
BM_StrokePolyline/stroke_Cubic_Butt_Round_uv            18785 ns        18691 ns        37180 SinglePointCount=946 TotalPointCount=35.1723M
BM_StrokePolyline/stroke_Cubic_Square_Bevel_uv           9321 ns         9296 ns        74695 SinglePointCount=906 TotalPointCount=67.6737M
BM_StrokePolyline/stroke_Cubic_Round_Bevel_uv            9391 ns         9328 ns        74795 SinglePointCount=906 TotalPointCount=67.7643M
BM_Polyline/quad_polyline                                3261 ns         3251 ns       213397 SinglePointCount=147 TotalPointCount=31.3694M
BM_Polyline/quad_polyline_tess                          28425 ns        28093 ns        24694 SinglePointCount=447 TotalPointCount=11.0382M
BM_StrokePolyline/stroke_Quadratic_Butt_Bevel            4686 ns         4662 ns       149020 SinglePointCount=890 TotalPointCount=132.628M
BM_StrokePolyline/stroke_Quadratic_Butt_Miter            5316 ns         5308 ns       131909 SinglePointCount=781 TotalPointCount=103.021M
BM_StrokePolyline/stroke_Quadratic_Butt_Round           16550 ns        16530 ns        42153 SinglePointCount=941 TotalPointCount=39.666M
BM_StrokePolyline/stroke_Quadratic_Square_Bevel          4666 ns         4659 ns       150954 SinglePointCount=890 TotalPointCount=134.349M
BM_StrokePolyline/stroke_Quadratic_Round_Bevel           4637 ns         4633 ns       151038 SinglePointCount=890 TotalPointCount=134.424M
BM_StrokePolyline/stroke_Quadratic_Butt_Bevel_uv         9016 ns         9007 ns        79549 SinglePointCount=890 TotalPointCount=70.7986M
BM_StrokePolyline/stroke_Quadratic_Butt_Miter_uv         8673 ns         8663 ns        80139 SinglePointCount=781 TotalPointCount=62.5886M
BM_StrokePolyline/stroke_Quadratic_Butt_Round_uv        18329 ns        18277 ns        38338 SinglePointCount=941 TotalPointCount=36.0761M
BM_StrokePolyline/stroke_Quadratic_Square_Bevel_uv       8883 ns         8874 ns        79421 SinglePointCount=890 TotalPointCount=70.6847M
BM_StrokePolyline/stroke_Quadratic_Round_Bevel_uv        8999 ns         8993 ns        74913 SinglePointCount=890 TotalPointCount=66.6726M
BM_Convex/rrect_convex                                   1163 ns         1162 ns       609475 SinglePointCount=36 TotalPointCount=21.9411M
BM_StrokePolyline/stroke_RRect_Butt_Bevel                 782 ns          781 ns       912159 SinglePointCount=115 TotalPointCount=104.898M
BM_StrokePolyline/stroke_RRect_Butt_Bevel_uv             1477 ns         1476 ns       475114 SinglePointCount=115 TotalPointCount=54.6381M

[jonahwilliams]

Why leave off combos like Square + Miter?

[flar]

I could add them. I just thought that we should test one attribute at a time, as I describe in the "notes" comment above.

[jonahwilliams]

Oh, yeah - makes sense. I don't think we need the full combinatorial set.

[flar]

Though all combinations are tested for both uv and non-uv. I could go either way on filling out the rest of the cap/join combinations. Note that it would take us from 5 to 9 variations * 2 path types * UV/nonUV

[jonahwilliams]

LGTM w/ question