1 /*
2 * Copyright 2017 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SkTaskGroup2D.h"
9
start()10 void SkTaskGroup2D::start() {
11 fThreadsGroup->batch(fThreadCnt, [this](int threadId){
12 this->work(threadId);
13 });
14 }
15
addColumn()16 void SkTaskGroup2D::addColumn() {
17 SkASSERT(!fIsFinishing); // we're not supposed to add more work after the calling of finish
18 fWidth++;
19 }
20
finish()21 void SkTaskGroup2D::finish() {
22 fIsFinishing.store(true, std::memory_order_relaxed);
23 fThreadsGroup->wait();
24 }
25
work(int threadId)26 void SkSpinningTaskGroup2D::work(int threadId) {
27 int& nextColumn = fRowData[threadId].fNextColumn;
28
29 while (true) {
30 SkASSERT(nextColumn <= fWidth);
31 if (this->isFinishing() && nextColumn >= fWidth) {
32 return;
33 }
34
35 if (nextColumn < fWidth) {
36 fWork(threadId, nextColumn);
37 nextColumn++;
38 }
39 }
40 }
41
SkFlexibleTaskGroup2D(Work2D && w,int h,SkExecutor * x,int t)42 SkFlexibleTaskGroup2D::SkFlexibleTaskGroup2D(Work2D&& w, int h, SkExecutor* x, int t)
43 : SkTaskGroup2D(std::move(w), h, x, t), fRowData(h), fThreadData(t) {
44 for (int i = 0; i < t; ++i) {
45 fThreadData[i].fRowIndex = i;
46 }
47 }
48
49
work(int threadId)50 void SkFlexibleTaskGroup2D::work(int threadId) {
51 int failCnt = 0;
52 int& rowIndex = fThreadData[threadId].fRowIndex;
53
54 // This loop looks for work to do as long as
55 // either 1. isFinishing is false
56 // or 2. isFinishing is true but some rows still have unfinished tasks
57 while (true) {
58 RowData& rowData = fRowData[rowIndex];
59 bool processed = false;
60
61 // The Android roller somehow gets a false-positive compile warning/error about the try-lock
62 // and unlock process. Hence we disable -Wthread-safety-analysis to bypass it.
63 #ifdef __clang__
64 #pragma clang diagnostic push
65 #pragma clang diagnostic ignored "-Wthread-safety-analysis"
66 #endif
67 if (rowData.fMutex.try_lock()) {
68 if (rowData.fNextColumn < fWidth) {
69 fWork(rowIndex, rowData.fNextColumn);
70 rowData.fNextColumn++;
71 processed = true;
72 } else {
73 // isFinishing can never go from true to false. Once it's true, we count how many
74 // times that a row is out of work. If that count reaches fHeight, then we're out of
75 // work for the whole group.
76 failCnt += this->isFinishing();
77 }
78 rowData.fMutex.unlock();
79 }
80 #ifdef __clang__
81 #pragma clang diagnostic pop
82 #endif
83
84 if (!processed) {
85 if (failCnt >= fHeight) {
86 return;
87 }
88 rowIndex = (rowIndex + 1) % fHeight;
89 }
90 }
91 }
92