Merge one segment at a time

No parallelism yet, but seems to improve performance.
This commit is contained in:
Raph Levien 2020-05-30 08:35:26 -07:00
parent 894ef156e1
commit 121f29fef6
7 changed files with 144 additions and 204 deletions

View file

@ -1016,7 +1016,7 @@ unsafe fn choose_compute_device(
devices: &[vk::PhysicalDevice],
surface: Option<&VkSurface>,
) -> Option<(vk::PhysicalDevice, u32)> {
for pdevice in &devices[1..] {
for pdevice in devices {
let props = instance.get_physical_device_queue_family_properties(*pdevice);
for (ix, info) in props.iter().enumerate() {
// Check for surface presentation support

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@ -181,10 +181,12 @@ fn main() -> Result<(), Error> {
println!("Coarse kernel time: {:.3}ms", (ts[2] - ts[1]) * 1e3);
println!("Render kernel time: {:.3}ms", (ts[3] - ts[2]) * 1e3);
/*
let mut data: Vec<u32> = Default::default();
device.read_buffer(&renderer.bin_buf, &mut data).unwrap();
device.read_buffer(&renderer.ptcl_buf, &mut data).unwrap();
piet_gpu::dump_k1_data(&data);
//trace_ptcl(&data);
*/
let mut img_data: Vec<u8> = Default::default();
// Note: because png can use a `&[u8]` slice, we could avoid an extra copy

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@ -43,7 +43,6 @@ layout(set = 0, binding = 3) buffer BinsBuf {
// Note: cudaraster has N_TILE + 1 to cut down on bank conflicts.
shared uint bitmaps[N_SLICE][N_TILE];
shared uint count[N_SLICE][N_TILE];
shared uint sh_my_tile;
shared uint sh_chunk_start[N_TILE];
shared float sh_right_edge[N_TILE];
@ -57,145 +56,138 @@ uint state_right_edge_index(uint partition_ix) {
void main() {
uint chunk_n = 0;
uint my_n_elements = n_elements;
while (true) {
if (gl_LocalInvocationID.x == 0) {
sh_my_tile = atomicAdd(tile_ix, 1);
uint my_partition = gl_WorkGroupID.x;
for (uint i = 0; i < N_SLICE; i++) {
bitmaps[i][gl_LocalInvocationID.x] = 0;
}
barrier();
// Read inputs and determine coverage of bins
uint element_ix = my_partition * N_TILE + gl_LocalInvocationID.x;
AnnotatedRef ref = AnnotatedRef(element_ix * Annotated_size);
uint tag = Annotated_Nop;
if (element_ix < my_n_elements) {
tag = Annotated_tag(ref);
}
int x0 = 0, y0 = 0, x1 = 0, y1 = 0;
float my_right_edge = INFINITY;
bool crosses_edge = false;
switch (tag) {
case Annotated_FillLine:
case Annotated_StrokeLine:
AnnoStrokeLineSeg line = Annotated_StrokeLine_read(ref);
x0 = int(floor((min(line.p0.x, line.p1.x) - line.stroke.x) * SX));
y0 = int(floor((min(line.p0.y, line.p1.y) - line.stroke.y) * SY));
x1 = int(ceil((max(line.p0.x, line.p1.x) + line.stroke.x) * SX));
y1 = int(ceil((max(line.p0.y, line.p1.y) + line.stroke.y) * SY));
crosses_edge = tag == Annotated_FillLine && ceil(line.p0.y * TSY) != ceil(line.p1.y * TSY);
break;
case Annotated_Fill:
case Annotated_Stroke:
// Note: we take advantage of the fact that fills and strokes
// have compatible layout.
AnnoFill fill = Annotated_Fill_read(ref);
x0 = int(floor(fill.bbox.x * SX));
y0 = int(floor(fill.bbox.y * SY));
x1 = int(ceil(fill.bbox.z * SX));
y1 = int(ceil(fill.bbox.w * SY));
// It probably makes more sense to track x1, to avoid having to redo
// the rounding to tile coords.
my_right_edge = fill.bbox.z;
break;
}
// If the last element in this partition is a fill edge, then we need to do a
// look-forward to find the right edge of its corresponding fill. That data is
// recorded in aggregates computed in the element processing pass.
if (gl_LocalInvocationID.x == N_TILE - 1 && tag == Annotated_FillLine) {
uint aggregate_ix = (my_partition + 1) * ELEMENT_BINNING_RATIO;
// This is sequential but the expectation is that the amount of
// look-forward is small (performance may degrade in the case
// of massively complex paths).
do {
my_right_edge = uintBitsToFloat(state[state_right_edge_index(aggregate_ix)]);
aggregate_ix++;
} while (isinf(my_right_edge));
}
// Now propagate right_edge backward, from fill to segment.
for (uint i = 0; i < LG_N_TILE; i++) {
// Note: we could try to cut down on write bandwidth here if the value hasn't
// changed, but not sure it's worth the complexity to track.
sh_right_edge[gl_LocalInvocationID.x] = my_right_edge;
barrier();
if (gl_LocalInvocationID.x + (1 << i) < N_TILE && isinf(my_right_edge)) {
my_right_edge = sh_right_edge[gl_LocalInvocationID.x + (1 << i)];
}
barrier();
uint my_tile = sh_my_tile;
if (my_tile * N_TILE >= my_n_elements) {
break;
}
}
if (crosses_edge) {
x1 = int(ceil(my_right_edge * SX));
}
for (uint i = 0; i < N_SLICE; i++) {
bitmaps[i][gl_LocalInvocationID.x] = 0;
// At this point, we run an iterator over the coverage area,
// trying to keep divergence low.
// Right now, it's just a bbox, but we'll get finer with
// segments.
x0 = clamp(x0, 0, N_TILE_X);
x1 = clamp(x1, x0, N_TILE_X);
y0 = clamp(y0, 0, N_TILE_Y);
y1 = clamp(y1, y0, N_TILE_Y);
if (x0 == x1) y1 = y0;
int x = x0, y = y0;
uint my_slice = gl_LocalInvocationID.x / 32;
uint my_mask = 1 << (gl_LocalInvocationID.x & 31);
while (y < y1) {
atomicOr(bitmaps[my_slice][y * N_TILE_X + x], my_mask);
x++;
if (x == x1) {
x = x0;
y++;
}
barrier();
}
// Read inputs and determine coverage of bins
uint element_ix = my_tile * N_TILE + gl_LocalInvocationID.x;
AnnotatedRef ref = AnnotatedRef(element_ix * Annotated_size);
uint tag = Annotated_Nop;
if (element_ix < my_n_elements) {
tag = Annotated_tag(ref);
}
int x0 = 0, y0 = 0, x1 = 0, y1 = 0;
float my_right_edge = INFINITY;
bool crosses_edge = false;
switch (tag) {
case Annotated_FillLine:
case Annotated_StrokeLine:
AnnoStrokeLineSeg line = Annotated_StrokeLine_read(ref);
x0 = int(floor((min(line.p0.x, line.p1.x) - line.stroke.x) * SX));
y0 = int(floor((min(line.p0.y, line.p1.y) - line.stroke.y) * SY));
x1 = int(ceil((max(line.p0.x, line.p1.x) + line.stroke.x) * SX));
y1 = int(ceil((max(line.p0.y, line.p1.y) + line.stroke.y) * SY));
crosses_edge = tag == Annotated_FillLine && ceil(line.p0.y * TSY) != ceil(line.p1.y * TSY);
break;
case Annotated_Fill:
case Annotated_Stroke:
// Note: we take advantage of the fact that fills and strokes
// have compatible layout.
AnnoFill fill = Annotated_Fill_read(ref);
x0 = int(floor(fill.bbox.x * SX));
y0 = int(floor(fill.bbox.y * SY));
x1 = int(ceil(fill.bbox.z * SX));
y1 = int(ceil(fill.bbox.w * SY));
// It probably makes more sense to track x1, to avoid having to redo
// the rounding to tile coords.
my_right_edge = fill.bbox.z;
break;
}
barrier();
// Allocate output segments.
uint element_count = 0;
for (uint i = 0; i < N_SLICE; i++) {
element_count += bitCount(bitmaps[i][gl_LocalInvocationID.x]);
count[i][gl_LocalInvocationID.x] = element_count;
}
// element_count is number of elements covering bin for this invocation.
uint chunk_start = 0;
if (element_count != 0) {
// TODO: aggregate atomic adds (subgroup is probably fastest)
chunk_start = atomicAdd(alloc, element_count * BinInstance_size);
sh_chunk_start[gl_LocalInvocationID.x] = chunk_start;
}
// Note: it might be more efficient for reading to do this in the
// other order (each bin is a contiguous sequence of partitions)
uint out_ix = (my_partition * N_TILE + gl_LocalInvocationID.x) * 2;
bins[out_ix] = element_count;
bins[out_ix + 1] = chunk_start;
// If the last element in this partition is a fill edge, then we need to do a
// look-forward to find the right edge of its corresponding fill. That data is
// recorded in aggregates computed in the element processing pass.
if (gl_LocalInvocationID.x == N_TILE - 1 && tag == Annotated_FillLine) {
uint aggregate_ix = (my_tile + 1) * ELEMENT_BINNING_RATIO;
// This is sequential but the expectation is that the amount of
// look-forward is small (performance may degrade in the case
// of massively complex paths).
do {
my_right_edge = uintBitsToFloat(state[state_right_edge_index(aggregate_ix)]);
aggregate_ix++;
} while (isinf(my_right_edge));
}
// Now propagate right_edge backward, from fill to segment.
for (uint i = 0; i < LG_N_TILE; i++) {
// Note: we could try to cut down on write bandwidth here if the value hasn't
// changed, but not sure it's worth the complexity to track.
sh_right_edge[gl_LocalInvocationID.x] = my_right_edge;
barrier();
if (gl_LocalInvocationID.x + (1 << i) < N_TILE && isinf(my_right_edge)) {
my_right_edge = sh_right_edge[gl_LocalInvocationID.x + (1 << i)];
barrier();
// Use similar strategy as Laine & Karras paper; loop over bbox of bins
// touched by this element
x = x0;
y = y0;
while (y < y1) {
uint bin_ix = y * N_TILE_X + x;
uint out_mask = bitmaps[my_slice][bin_ix];
if ((out_mask & my_mask) != 0) {
uint idx = bitCount(out_mask & (my_mask - 1));
if (my_slice > 0) {
idx += count[my_slice - 1][bin_ix];
}
barrier();
uint out_offset = sh_chunk_start[bin_ix] + idx * BinInstance_size;
BinInstance_write(BinInstanceRef(out_offset), BinInstance(element_ix, my_right_edge));
}
if (crosses_edge) {
x1 = int(ceil(my_right_edge * SX));
}
// At this point, we run an iterator over the coverage area,
// trying to keep divergence low.
// Right now, it's just a bbox, but we'll get finer with
// segments.
x0 = clamp(x0, 0, N_TILE_X);
x1 = clamp(x1, x0, N_TILE_X);
y0 = clamp(y0, 0, N_TILE_Y);
y1 = clamp(y1, y0, N_TILE_Y);
if (x0 == x1) y1 = y0;
int x = x0, y = y0;
uint my_slice = gl_LocalInvocationID.x / 32;
uint my_mask = 1 << (gl_LocalInvocationID.x & 31);
while (y < y1) {
atomicOr(bitmaps[my_slice][y * N_TILE_X + x], my_mask);
x++;
if (x == x1) {
x = x0;
y++;
}
}
barrier();
// Allocate output segments.
uint element_count = 0;
for (uint i = 0; i < N_SLICE; i++) {
element_count += bitCount(bitmaps[i][gl_LocalInvocationID.x]);
count[i][gl_LocalInvocationID.x] = element_count;
}
// element_count is number of elements covering bin for this invocation.
uint chunk_start = 0;
if (element_count != 0) {
// TODO: aggregate atomic adds (subgroup is probably fastest)
chunk_start = atomicAdd(alloc, element_count * BinInstance_size);
sh_chunk_start[gl_LocalInvocationID.x] = chunk_start;
}
uint out_ix = (my_tile * N_TILE + gl_LocalInvocationID.x) * 2;
bins[out_ix] = element_count;
bins[out_ix + 1] = chunk_start;
barrier();
// Use similar strategy as Laine & Karras paper; loop over bbox of bins
// touched by this element
x = x0;
y = y0;
while (y < y1) {
uint bin_ix = y * N_TILE_X + x;
uint out_mask = bitmaps[my_slice][bin_ix];
if ((out_mask & my_mask) != 0) {
uint idx = bitCount(out_mask & (my_mask - 1));
if (my_slice > 0) {
idx += count[my_slice - 1][bin_ix];
}
uint out_offset = sh_chunk_start[bin_ix] + idx * BinInstance_size;
BinInstance_write(BinInstanceRef(out_offset), BinInstance(element_ix, my_right_edge));
}
x++;
if (x == x1) {
x = x0;
y++;
}
x++;
if (x == x1) {
x = x0;
y++;
}
}
}

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@ -16,6 +16,7 @@ layout(set = 0, binding = 1) buffer BinsBuf {
};
layout(set = 0, binding = 2) buffer AllocBuf {
uint n_elements;
uint alloc;
};
@ -31,15 +32,6 @@ layout(set = 0, binding = 3) buffer PtclBuf {
shared uint sh_elements[N_RINGBUF];
shared float sh_right_edge[N_RINGBUF];
shared uint sh_chunk[N_WG];
shared uint sh_chunk_next[N_WG];
shared uint sh_chunk_n[N_WG];
shared uint sh_min_buf;
// Some of these are kept in shared memory to ease register
// pressure, but it could go either way.
shared uint sh_first_el[N_WG];
shared uint sh_selected_n;
shared uint sh_elements_ref;
shared uint sh_bitmaps[N_SLICE][N_TILE];
shared uint sh_backdrop[N_SLICE][N_TILE];
@ -96,14 +88,16 @@ void main() {
// Could use either linear or 2d layouts for both dispatch and
// invocations within the workgroup. We'll use variables to abstract.
uint bin_ix = N_TILE_X * gl_WorkGroupID.y + gl_WorkGroupID.x;
uint partition_ix = 0;
uint my_n_elements = n_elements;
// Top left coordinates of this bin.
vec2 xy0 = vec2(N_TILE_X * TILE_WIDTH_PX * gl_WorkGroupID.x, N_TILE_Y * TILE_HEIGHT_PX * gl_WorkGroupID.y);
uint th_ix = gl_LocalInvocationID.x;
uint tile_x = N_TILE_X * gl_WorkGroupID.x + gl_LocalInvocationID.x % N_TILE_X;
uint tile_y = N_TILE_Y * gl_WorkGroupID.y + gl_LocalInvocationID.x / N_TILE_X;
uint tile_ix = tile_y * WIDTH_IN_TILES + tile_x;
CmdRef cmd_ref = CmdRef(tile_ix * PTCL_INITIAL_ALLOC);
uint this_tile_ix = tile_y * WIDTH_IN_TILES + tile_x;
CmdRef cmd_ref = CmdRef(this_tile_ix * PTCL_INITIAL_ALLOC);
uint cmd_limit = cmd_ref.offset + PTCL_INITIAL_ALLOC - 2 * Cmd_size;
// Allocation and management of segment output
@ -115,16 +109,6 @@ void main() {
uint wr_ix = 0;
uint rd_ix = 0;
uint first_el;
if (th_ix < N_WG) {
uint start_chunk = (bin_ix * N_WG + th_ix) * BIN_INITIAL_ALLOC;
sh_chunk[th_ix] = start_chunk;
BinChunk chunk = BinChunk_read(BinChunkRef(start_chunk));
sh_chunk_n[th_ix] = chunk.n;
sh_chunk_next[th_ix] = chunk.next.offset;
sh_first_el[th_ix] = chunk.n > 0 ?
BinInstance_read(BinInstanceRef(start_chunk + BinChunk_size)).element_ix : ~0;
}
if (th_ix < N_SLICE) {
sh_bd_sign[th_ix] = 0;
}
@ -138,47 +122,11 @@ void main() {
sh_is_segment[th_ix] = 0;
}
while (wr_ix - rd_ix <= N_TILE) {
// Choose segment with least element.
uint my_min;
if (th_ix < N_WG) {
if (th_ix == 0) {
sh_selected_n = 0;
sh_min_buf = ~0;
}
}
barrier();
// Tempting to do this with subgroups, but atomic should be good enough.
if (th_ix < N_WG) {
my_min = sh_first_el[th_ix];
atomicMin(sh_min_buf, my_min);
}
barrier();
if (th_ix < N_WG) {
if (my_min == sh_min_buf && my_min != ~0) {
sh_elements_ref = sh_chunk[th_ix] + BinChunk_size;
uint selected_n = sh_chunk_n[th_ix];
sh_selected_n = selected_n;
uint next_chunk = sh_chunk_next[th_ix];
if (next_chunk == 0) {
sh_first_el[th_ix] = ~0;
} else {
sh_chunk[th_ix] = next_chunk;
BinChunk chunk = BinChunk_read(BinChunkRef(next_chunk));
sh_chunk_n[th_ix] = chunk.n;
sh_chunk_next[th_ix] = chunk.next.offset;
sh_first_el[th_ix] = BinInstance_read(
BinInstanceRef(next_chunk + BinChunk_size)).element_ix;
}
}
}
barrier();
uint chunk_n = sh_selected_n;
if (chunk_n == 0) {
// All chunks consumed
break;
}
BinInstanceRef inst_ref = BinInstanceRef(sh_elements_ref);
while (wr_ix - rd_ix <= N_TILE && partition_ix * N_TILE < my_n_elements) {
uint in_ix = (partition_ix * N_TILE + bin_ix) * 2;
uint chunk_n = bins[in_ix];
uint elements_ref = bins[in_ix + 1];
BinInstanceRef inst_ref = BinInstanceRef(elements_ref);
if (th_ix < chunk_n) {
BinInstance inst = BinInstance_read(BinInstance_index(inst_ref, th_ix));
uint wr_el_ix = (wr_ix + th_ix) % N_RINGBUF;
@ -186,6 +134,7 @@ void main() {
sh_right_edge[wr_el_ix] = inst.right_edge;
}
wr_ix += chunk_n;
partition_ix++;
}
barrier();

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@ -160,7 +160,7 @@ impl<D: Device> Renderer<D> {
let state_buf = device.create_buffer(1 * 1024 * 1024, dev)?;
let anno_buf = device.create_buffer(64 * 1024 * 1024, dev)?;
let bin_buf = device.create_buffer(64 * 1024 * 1024, host)?;
let bin_buf = device.create_buffer(64 * 1024 * 1024, dev)?;
let ptcl_buf = device.create_buffer(48 * 1024 * 1024, dev)?;
let image_dev = device.create_image2d(WIDTH as u32, HEIGHT as u32, dev)?;
@ -192,12 +192,13 @@ impl<D: Device> Renderer<D> {
&[],
)?;
let coarse_alloc_buf_host = device.create_buffer(4, host)?;
let coarse_alloc_buf_dev = device.create_buffer(4, dev)?;
let coarse_alloc_buf_host = device.create_buffer(8, host)?;
let coarse_alloc_buf_dev = device.create_buffer(8, dev)?;
let coarse_alloc_start = WIDTH_IN_TILES * HEIGHT_IN_TILES * PTCL_INITIAL_ALLOC;
device
.write_buffer(&coarse_alloc_buf_host, &[
n_elements as u32,
coarse_alloc_start as u32,
])
?;
@ -264,26 +265,22 @@ impl<D: Device> Renderer<D> {
cmd_buf.dispatch(
&self.bin_pipeline,
&self.bin_ds,
(N_WG, 1, 1),
(((self.n_elements + 255) / 256) as u32, 1, 1),
);
cmd_buf.write_timestamp(&query_pool, 2);
cmd_buf.memory_barrier();
/*
cmd_buf.dispatch(
&self.coarse_pipeline,
&self.coarse_ds,
(WIDTH as u32 / 256, HEIGHT as u32 / 256, 1),
);
*/
cmd_buf.write_timestamp(&query_pool, 3);
cmd_buf.memory_barrier();
/*
cmd_buf.dispatch(
&self.k4_pipeline,
&self.k4_ds,
((WIDTH / TILE_W) as u32, (HEIGHT / TILE_H) as u32, 1),
);
*/
cmd_buf.write_timestamp(&query_pool, 4);
cmd_buf.memory_barrier();
cmd_buf.image_barrier(&self.image_dev, ImageLayout::General, ImageLayout::BlitSrc);