ref: 1f4a6c8a4e92addc5624a8b55dd9cf6a05797dcc
parent: fb209003a8b9f1c52b2512391a74004b898e749c
author: James Zern <[email protected]>
date: Fri Sep 25 16:43:04 EDT 2015
vp9/tile_worker_hook: add multiple tile decoding this reduces the number of synchronizations in decode_tiles_mt() and improves overall performance when the number of threads is less than the number of tiles Change-Id: Iaee6082673dc187ffe0e3d91a701d1e470c62924
--- a/vp9/decoder/vp9_decodeframe.c
+++ b/vp9/decoder/vp9_decodeframe.c
@@ -1369,12 +1369,6 @@
cm->log2_tile_rows += vpx_rb_read_bit(rb);
}
-typedef struct TileBuffer {- const uint8_t *data;
- size_t size;
- int col; // only used with multi-threaded decoding
-} TileBuffer;
-
// Reads the next tile returning its size and adjusting '*data' accordingly
// based on 'is_last'.
static void get_tile_buffer(const uint8_t *const data_end,
@@ -1573,31 +1567,56 @@
return vpx_reader_find_end(&tile_data->bit_reader);
}
+// On entry 'tile_data->data_end' points to the end of the input frame, on exit
+// it is updated to reflect the bitreader position of the final tile column if
+// present in the tile buffer group or NULL otherwise.
static int tile_worker_hook(TileWorkerData *const tile_data, void *unused) {- const TileInfo *const tile = &tile_data->xd.tile;
- int mi_row, mi_col;
+ TileInfo *const tile = &tile_data->xd.tile;
+ VP9Decoder *const pbi = tile_data->pbi;
+ const int final_col = (1 << pbi->common.log2_tile_cols) - 1;
+ const uint8_t *volatile bit_reader_end = NULL;
+ volatile int n = tile_data->buf_start;
+ tile_data->error_info.setjmp = 1;
(void)unused;
if (setjmp(tile_data->error_info.jmp)) {tile_data->error_info.setjmp = 0;
tile_data->xd.corrupted = 1;
+ tile_data->data_end = NULL;
return 0;
}
- tile_data->error_info.setjmp = 1;
tile_data->xd.error_info = &tile_data->error_info;
+ tile_data->xd.corrupted = 0;
- for (mi_row = tile->mi_row_start; mi_row < tile->mi_row_end;
- mi_row += MI_BLOCK_SIZE) {- vp9_zero(tile_data->xd.left_context);
- vp9_zero(tile_data->xd.left_seg_context);
- for (mi_col = tile->mi_col_start; mi_col < tile->mi_col_end;
- mi_col += MI_BLOCK_SIZE) {- decode_partition(tile_data->pbi, &tile_data->xd,
- mi_row, mi_col, &tile_data->bit_reader,
- BLOCK_64X64, 4);
+ do {+ int mi_row, mi_col;
+ const TileBuffer *const buf = pbi->tile_buffers + n;
+ vp9_zero(tile_data->dqcoeff);
+ vp9_tile_init(tile, &pbi->common, 0, buf->col);
+ setup_token_decoder(buf->data, tile_data->data_end, buf->size,
+ &tile_data->error_info, &tile_data->bit_reader,
+ pbi->decrypt_cb, pbi->decrypt_state);
+ vp9_init_macroblockd(&pbi->common, &tile_data->xd, tile_data->dqcoeff);
+
+ for (mi_row = tile->mi_row_start; mi_row < tile->mi_row_end;
+ mi_row += MI_BLOCK_SIZE) {+ vp9_zero(tile_data->xd.left_context);
+ vp9_zero(tile_data->xd.left_seg_context);
+ for (mi_col = tile->mi_col_start; mi_col < tile->mi_col_end;
+ mi_col += MI_BLOCK_SIZE) {+ decode_partition(tile_data->pbi, &tile_data->xd,
+ mi_row, mi_col, &tile_data->bit_reader,
+ BLOCK_64X64, 4);
+ }
}
- }
+
+ if (buf->col == final_col) {+ bit_reader_end = vpx_reader_find_end(&tile_data->bit_reader);
+ }
+ } while (!tile_data->xd.corrupted && ++n <= tile_data->buf_end);
+
+ tile_data->data_end = bit_reader_end;
return !tile_data->xd.corrupted;
}
@@ -1617,19 +1636,15 @@
const int aligned_mi_cols = mi_cols_aligned_to_sb(cm->mi_cols);
const int tile_cols = 1 << cm->log2_tile_cols;
const int tile_rows = 1 << cm->log2_tile_rows;
- const int num_workers = VPXMIN(pbi->max_threads & ~1, tile_cols);
- TileBuffer tile_buffers[1][1 << 6];
+ const int num_workers = VPXMIN(pbi->max_threads, tile_cols);
int n;
- int final_worker = -1;
assert(tile_cols <= (1 << 6));
assert(tile_rows == 1);
(void)tile_rows;
- // TODO(jzern): See if we can remove the restriction of passing in max
- // threads to the decoder.
if (pbi->num_tile_workers == 0) {- const int num_threads = pbi->max_threads & ~1;
+ const int num_threads = pbi->max_threads;
int i;
CHECK_MEM_ERROR(cm, pbi->tile_workers,
vpx_malloc(num_threads * sizeof(*pbi->tile_workers)));
@@ -1675,25 +1690,34 @@
vp9_reset_lfm(cm);
// Load tile data into tile_buffers
- get_tile_buffers(pbi, data, data_end, tile_cols, tile_rows, tile_buffers);
+ get_tile_buffers(pbi, data, data_end, tile_cols, tile_rows,
+ &pbi->tile_buffers);
// Sort the buffers based on size in descending order.
- qsort(tile_buffers[0], tile_cols, sizeof(tile_buffers[0][0]),
+ qsort(pbi->tile_buffers, tile_cols, sizeof(pbi->tile_buffers[0]),
compare_tile_buffers);
- // Rearrange the tile buffers such that per-tile group the largest, and
- // presumably the most difficult, tile will be decoded in the main thread.
- // This should help minimize the number of instances where the main thread is
- // waiting for a worker to complete.
- {- int group_start = 0;
- while (group_start < tile_cols) {- const TileBuffer largest = tile_buffers[0][group_start];
- const int group_end = VPXMIN(group_start + num_workers, tile_cols) - 1;
- memmove(tile_buffers[0] + group_start, tile_buffers[0] + group_start + 1,
- (group_end - group_start) * sizeof(tile_buffers[0][0]));
- tile_buffers[0][group_end] = largest;
- group_start = group_end + 1;
+ if (num_workers == tile_cols) {+ // Rearrange the tile buffers such that the largest, and
+ // presumably the most difficult, tile will be decoded in the main thread.
+ // This should help minimize the number of instances where the main thread
+ // is waiting for a worker to complete.
+ const TileBuffer largest = pbi->tile_buffers[0];
+ memmove(pbi->tile_buffers, pbi->tile_buffers + 1,
+ (tile_cols - 1) * sizeof(pbi->tile_buffers[0]));
+ pbi->tile_buffers[tile_cols - 1] = largest;
+ } else {+ int start = 0, end = tile_cols - 2;
+ TileBuffer tmp;
+
+ // Interleave the tiles to distribute the load between threads, assuming a
+ // larger tile implies it is more difficult to decode.
+ while (start < end) {+ tmp = pbi->tile_buffers[start];
+ pbi->tile_buffers[start] = pbi->tile_buffers[end];
+ pbi->tile_buffers[end] = tmp;
+ start += 2;
+ end -= 2;
}
}
@@ -1708,50 +1732,40 @@
}
}
- n = 0;
- while (n < tile_cols) {- int i;
- for (i = 0; i < num_workers && n < tile_cols; ++i) {- VPxWorker *const worker = &pbi->tile_workers[i];
+ {+ const int base = tile_cols / num_workers;
+ const int remain = tile_cols % num_workers;
+ int buf_start = 0;
+
+ for (n = 0; n < num_workers; ++n) {+ const int count = base + (remain + n) / num_workers;
+ VPxWorker *const worker = &pbi->tile_workers[n];
TileWorkerData *const tile_data = (TileWorkerData*)worker->data1;
- TileBuffer *const buf = &tile_buffers[0][n];
- tile_data->xd.corrupted = 0;
- vp9_zero(tile_data->dqcoeff);
- vp9_tile_init(&tile_data->xd.tile, cm, 0, buf->col);
- setup_token_decoder(buf->data, data_end, buf->size, &cm->error,
- &tile_data->bit_reader, pbi->decrypt_cb,
- pbi->decrypt_state);
- vp9_init_macroblockd(cm, &tile_data->xd, tile_data->dqcoeff);
+ tile_data->buf_start = buf_start;
+ tile_data->buf_end = buf_start + count - 1;
+ tile_data->data_end = data_end;
+ buf_start += count;
worker->had_error = 0;
- if (i == num_workers - 1 || n == tile_cols - 1) {+ if (n == num_workers - 1) {+ assert(tile_data->buf_end == tile_cols - 1);
winterface->execute(worker);
} else {winterface->launch(worker);
}
-
- if (buf->col == tile_cols - 1) {- final_worker = i;
- }
-
- ++n;
}
- for (; i > 0; --i) {- VPxWorker *const worker = &pbi->tile_workers[i - 1];
+ for (; n > 0; --n) {+ VPxWorker *const worker = &pbi->tile_workers[n - 1];
+ TileWorkerData *const tile_data = (TileWorkerData*)worker->data1;
// TODO(jzern): The tile may have specific error data associated with
// its vpx_internal_error_info which could be propagated to the main info
// in cm. Additionally once the threads have been synced and an error is
// detected, there's no point in continuing to decode tiles.
pbi->mb.corrupted |= !winterface->sync(worker);
+ if (!bit_reader_end) bit_reader_end = tile_data->data_end;
}
- if (final_worker > -1) {- TileWorkerData *const tile_data =
- (TileWorkerData*)pbi->tile_workers[final_worker].data1;
- bit_reader_end = vpx_reader_find_end(&tile_data->bit_reader);
- final_worker = -1;
- }
}
// Accumulate thread frame counts.
@@ -1764,6 +1778,7 @@
}
}
+ assert(bit_reader_end || pbi->mb.corrupted);
return bit_reader_end;
}
--- a/vp9/decoder/vp9_decoder.h
+++ b/vp9/decoder/vp9_decoder.h
@@ -36,8 +36,16 @@
DECLARE_ALIGNED(16, tran_low_t, dqcoeff[32 * 32]);
} TileData;
+typedef struct TileBuffer {+ const uint8_t *data;
+ size_t size;
+ int col; // only used with multi-threaded decoding
+} TileBuffer;
+
typedef struct TileWorkerData {struct VP9Decoder *pbi;
+ const uint8_t *data_end;
+ int buf_start, buf_end; // pbi->tile_buffers to decode, inclusive
vpx_reader bit_reader;
FRAME_COUNTS counts;
DECLARE_ALIGNED(16, MACROBLOCKD, xd);
@@ -65,6 +73,7 @@
VPxWorker lf_worker;
VPxWorker *tile_workers;
TileWorkerData *tile_worker_data;
+ TileBuffer tile_buffers[64];
int num_tile_workers;
TileData *tile_data;