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Improve task decomposition in ray tracing example.

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Specifically, launch all of the tasks in one statement, rather than
still looping over spans in y and launching a collection of tasks
across x for each span.  This seems to give a few percent better
performance.
This commit is contained in:
Matt Pharr
2011-10-04 09:33:59 -07:00
parent 5f78edf07a
commit 0933a77c1b
1 changed files with 14 additions and 14 deletions
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26
examples/rt/rt.ispc
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@@ -283,19 +283,19 @@ export void raytrace_ispc(uniform int width, uniform int height,
}
task void raytrace_tile_task(uniform int y0, uniform int y1,
uniform int width, uniform int height,
task void raytrace_tile_task(uniform int width, uniform int height,
uniform int baseWidth, uniform int baseHeight,
const uniform float raster2camera[4][4],
const uniform float camera2world[4][4],
uniform float image[], uniform int id[],
const LinearBVHNode nodes[],
const Triangle triangles[]) {
uniform int dx = 16; // must match dx below
uniform int xTasks = (width + (dx-1)) / dx;
uniform int x0 = (taskIndex % xTasks) * dx;
uniform int x1 = x0 + dx;
x1 = min(x1, width);
uniform int dx = 16, dy = 16; // must match dx, dy below
uniform int xBuckets = (width + (dx-1)) / dx;
uniform int x0 = (taskIndex % xBuckets) * dx;
uniform int x1 = min(x0 + dx, width);
uniform int y0 = (taskIndex / xBuckets) * dy;
uniform int y1 = min(y0 + dy, height);
raytrace_tile(x0, x1, y0, y1, width, height, baseWidth, baseHeight,
raster2camera, camera2world, image,
@@ -311,11 +311,11 @@ export void raytrace_ispc_tasks(uniform int width, uniform int height,
const LinearBVHNode nodes[],
const Triangle triangles[]) {
uniform int dx = 16, dy = 16;
uniform int nTasks = (width + (dx-1)) / dx;
for (uniform int y = 0; y < height; y += dy) {
uniform int y1 = min(y + dy, height);
launch[nTasks] < raytrace_tile_task(y, y1, width, height, baseWidth,
baseHeight, raster2camera, camera2world,
uniform int xBuckets = (width + (dx-1)) / dx;
uniform int yBuckets = (height + (dy-1)) / dy;
uniform int nTasks = xBuckets * yBuckets;
launch[nTasks] < raytrace_tile_task(width, height, baseWidth, baseHeight,
raster2camera, camera2world,
image, id, nodes, triangles) >;
}
}