SkThreadPool ~~> SkTaskGroup

SkTaskGroup is like SkThreadPool except the threads stay in
one global pool.  Each SkTaskGroup itself is tiny (4 bytes)
and its wait() method applies only to tasks add()ed to that
instance, not the whole thread pool.

This means we don't need to bring up new thread pools when
tests themselves want to use multithreading (e.g. pathops,
quilt).  We just create a new SkTaskGroup and wait for that
to complete.  This should be more efficient, and allow us
to expand where we use threads to really latency sensitive
places.  E.g. we can probably now use these in nanobench
for CPU .skp rendering.

Now that all threads are sharing the same pool, I think we
can remove most of the custom mechanism pathops tests use
to control threading.  They'll just ride on the global pool
with all other tests now.

This (temporarily?) removes the GPU multithreading feature
from DM, which we don't use.

On my desktop, DM runs a little faster (57s -> 55s) in
Debug, and a lot faster in Release (36s -> 24s).  The bots
show speedups of similar proportions, cutting more than a
minute off the N4/Release and Win7/Debug runtimes.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/9c7207b5dc71dc5a96a2eb107d401133333d5b6f

R=caryclark@google.com, bsalomon@google.com, bungeman@google.com, mtklein@google.com, reed@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/531653002

20 files changed, 61 insertions, 88 deletions

diff --git a/tests/OnceTest.cpp b/tests/OnceTest.cpp
index 389d257b73..192abaaee3 100644
--- a/tests/OnceTest.cpp
+++ b/tests/OnceTest.cpp
@@ -6,7 +6,7 @@
  */
 
 #include "SkOnce.h"
-#include "SkThreadPool.h"
+#include "SkTaskGroup.h"
 #include "Test.h"
 
 static void add_five(int* x) {
@@ -42,7 +42,7 @@ public:
 };
 
 DEF_TEST(SkOnce_Multithreaded, r) {
-    const int kTasks = 16, kThreads = 4;
+    const int kTasks = 16;
 
     // Make a bunch of tasks that will race to be the first to add six to x.
     Racer racers[kTasks];
@@ -54,11 +54,11 @@ DEF_TEST(SkOnce_Multithreaded, r) {
     }
 
     // Let them race.
-    SkThreadPool pool(kThreads);
+    SkTaskGroup tg;
     for (int i = 0; i < kTasks; i++) {
-        pool.add(&racers[i]);
+        tg.add(&racers[i]);
     }
-    pool.wait();
+    tg.wait();
 
     // Only one should have done the +=.
     REPORTER_ASSERT(r, 6 == x);
diff --git a/tests/PathOpsExtendedTest.cpp b/tests/PathOpsExtendedTest.cpp
index 05d00045b9..f90b9fec69 100644
--- a/tests/PathOpsExtendedTest.cpp
+++ b/tests/PathOpsExtendedTest.cpp
@@ -14,8 +14,8 @@
 #include "SkPaint.h"
 #include "SkRTConf.h"
 #include "SkStream.h"
+#include "SkTaskGroup.h"
 #include "SkThread.h"
-#include "SkThreadPool.h"
 
 #ifdef SK_BUILD_FOR_MAC
 #include <sys/sysctl.h>
@@ -542,7 +542,7 @@ bool testThreadedPathOp(skiatest::Reporter* reporter, const SkPath& a, const SkP
 
 SK_DECLARE_STATIC_MUTEX(gMutex);
 
-int initializeTests(skiatest::Reporter* reporter, const char* test) {
+void initializeTests(skiatest::Reporter* reporter, const char* test) {
 #if 0  // doesn't work yet
     SK_CONF_SET("images.jpeg.suppressDecoderWarnings", true);
     SK_CONF_SET("images.png.suppressDecoderWarnings", true);
@@ -566,7 +566,6 @@ int initializeTests(skiatest::Reporter* reporter, const char* test) {
             }
         }
     }
-    return reporter->allowThreaded() ? SkThreadPool::kThreadPerCore : 1;
 }
 
 void outputProgress(char* ramStr, const char* pathStr, SkPath::FillType pathFillType) {
diff --git a/tests/PathOpsExtendedTest.h b/tests/PathOpsExtendedTest.h
index 5f3413c572..a854410139 100644
--- a/tests/PathOpsExtendedTest.h
+++ b/tests/PathOpsExtendedTest.h
@@ -36,7 +36,7 @@ extern bool testSimplify(SkPath& path, bool useXor, SkPath& out, PathOpsThreadSt
                          const char* pathStr);
 extern bool testSimplify(skiatest::Reporter* reporter, const SkPath& path, const char* filename);
 
-int initializeTests(skiatest::Reporter* reporter, const char* testName);
+void initializeTests(skiatest::Reporter* reporter, const char* testName);
 void outputProgress(char* ramStr, const char* pathStr, SkPath::FillType );
 void outputProgress(char* ramStr, const char* pathStr, SkPathOp op);
 
diff --git a/tests/PathOpsOpCubicThreadedTest.cpp b/tests/PathOpsOpCubicThreadedTest.cpp
index 889ade0487..751ccc5f1b 100644
--- a/tests/PathOpsOpCubicThreadedTest.cpp
+++ b/tests/PathOpsOpCubicThreadedTest.cpp
@@ -67,8 +67,8 @@ static void testOpCubicsMain(PathOpsThreadState* data) {
 }
 
 DEF_TEST(PathOpsOpCubicsThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "cubicOp");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "cubicOp");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 6; ++a) {  // outermost
         for (int b = a + 1; b < 7; ++b) {
             for (int c = 0 ; c < 6; ++c) {
diff --git a/tests/PathOpsOpLoopThreadedTest.cpp b/tests/PathOpsOpLoopThreadedTest.cpp
index 71efff3edc..3f316d1fe9 100755
--- a/tests/PathOpsOpLoopThreadedTest.cpp
+++ b/tests/PathOpsOpLoopThreadedTest.cpp
@@ -62,8 +62,8 @@ static void testOpLoopsMain(PathOpsThreadState* data) {
 }
 
 DEF_TEST(PathOpsOpLoopsThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "cubicOp");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "cubicOp");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 6; ++a) {  // outermost
         for (int b = a + 1; b < 7; ++b) {
             for (int c = 0 ; c < 6; ++c) {
@@ -81,7 +81,7 @@ finish:
 }
 
 DEF_TEST(PathOpsOpLoops, reporter) {
-    (void) initializeTests(reporter, "cubicOp");
+    initializeTests(reporter, "cubicOp");
     PathOpsThreadState state;
     state.fReporter = reporter;
     SkBitmap bitmap;
diff --git a/tests/PathOpsOpRectThreadedTest.cpp b/tests/PathOpsOpRectThreadedTest.cpp
index 3d07d74bb0..1b6e4e86b9 100644
--- a/tests/PathOpsOpRectThreadedTest.cpp
+++ b/tests/PathOpsOpRectThreadedTest.cpp
@@ -74,8 +74,8 @@ static void testPathOpsRectsMain(PathOpsThreadState* data)
 }
 
 DEF_TEST(PathOpsRectsThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "testOp");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "testOp");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 6; ++a) {  // outermost
         for (int b = a + 1; b < 7; ++b) {
             for (int c = 0 ; c < 6; ++c) {
diff --git a/tests/PathOpsQuadLineIntersectionThreadedTest.cpp b/tests/PathOpsQuadLineIntersectionThreadedTest.cpp
index fd7581fa58..7e33b7b374 100644
--- a/tests/PathOpsQuadLineIntersectionThreadedTest.cpp
+++ b/tests/PathOpsQuadLineIntersectionThreadedTest.cpp
@@ -111,8 +111,8 @@ static void testQuadLineIntersectMain(PathOpsThreadState* data)
 }
 
 DEF_TEST(PathOpsQuadLineIntersectionThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "testQuadLineIntersect");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "testQuadLineIntersect");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 16; ++a) {
         for (int b = 0 ; b < 16; ++b) {
             for (int c = 0 ; c < 16; ++c) {
diff --git a/tests/PathOpsSimplifyDegenerateThreadedTest.cpp b/tests/PathOpsSimplifyDegenerateThreadedTest.cpp
index 5cd3c35d8a..8e8c58bf44 100755
--- a/tests/PathOpsSimplifyDegenerateThreadedTest.cpp
+++ b/tests/PathOpsSimplifyDegenerateThreadedTest.cpp
@@ -68,8 +68,8 @@ static void testSimplifyDegeneratesMain(PathOpsThreadState* data) {
 }
 
 DEF_TEST(PathOpsSimplifyDegeneratesThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "testDegenerates");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "testDegenerates");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 16; ++a) {
         int ax = a & 0x03;
         int ay = a >> 2;
diff --git a/tests/PathOpsSimplifyQuadThreadedTest.cpp b/tests/PathOpsSimplifyQuadThreadedTest.cpp
index dbbec3e3e6..3c92cca217 100644
--- a/tests/PathOpsSimplifyQuadThreadedTest.cpp
+++ b/tests/PathOpsSimplifyQuadThreadedTest.cpp
@@ -74,8 +74,8 @@ static void testSimplifyQuadsMain(PathOpsThreadState* data)
 }
 
 DEF_TEST(PathOpsSimplifyQuadsThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "testQuads");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "testQuads");
+    PathOpsThreadedTestRunner testRunner(reporter);
     int a = 0;
     for (; a < 16; ++a) {
         for (int b = a ; b < 16; ++b) {
diff --git a/tests/PathOpsSimplifyQuadralateralsThreadedTest.cpp b/tests/PathOpsSimplifyQuadralateralsThreadedTest.cpp
index afa9200389..f8e9a6e3dc 100755
--- a/tests/PathOpsSimplifyQuadralateralsThreadedTest.cpp
+++ b/tests/PathOpsSimplifyQuadralateralsThreadedTest.cpp
@@ -76,8 +76,8 @@ static void testSimplifyQuadralateralsMain(PathOpsThreadState* data)
 }
 
 DEF_TEST(PathOpsSimplifyQuadralateralsThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "testQuadralaterals");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "testQuadralaterals");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 16; ++a) {
         for (int b = a ; b < 16; ++b) {
             for (int c = b ; c < 16; ++c) {
diff --git a/tests/PathOpsSimplifyRectThreadedTest.cpp b/tests/PathOpsSimplifyRectThreadedTest.cpp
index 9e6a5eaf03..52a78ece84 100644
--- a/tests/PathOpsSimplifyRectThreadedTest.cpp
+++ b/tests/PathOpsSimplifyRectThreadedTest.cpp
@@ -187,8 +187,8 @@ static void testSimplify4x4RectsMain(PathOpsThreadState* data)
 }
 
 DEF_TEST(PathOpsSimplifyRectsThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "testLine");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "testLine");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 8; ++a) {  // outermost
         for (int b = a ; b < 8; ++b) {
             for (int c = b ; c < 8; ++c) {
diff --git a/tests/PathOpsSimplifyTrianglesThreadedTest.cpp b/tests/PathOpsSimplifyTrianglesThreadedTest.cpp
index b5d6508846..ee0ca2bcaa 100755
--- a/tests/PathOpsSimplifyTrianglesThreadedTest.cpp
+++ b/tests/PathOpsSimplifyTrianglesThreadedTest.cpp
@@ -73,8 +73,8 @@ static void testSimplifyTrianglesMain(PathOpsThreadState* data) {
 }
 
 DEF_TEST(PathOpsSimplifyTrianglesThreaded, reporter) {
-    int threadCount = initializeTests(reporter, "testTriangles");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "testTriangles");
+    PathOpsThreadedTestRunner testRunner(reporter);
     for (int a = 0; a < 15; ++a) {
         int ax = a & 0x03;
         int ay = a >> 2;
diff --git a/tests/PathOpsSkpClipTest.cpp b/tests/PathOpsSkpClipTest.cpp
index cdc3c1fcd9..0769141685 100755
--- a/tests/PathOpsSkpClipTest.cpp
+++ b/tests/PathOpsSkpClipTest.cpp
@@ -20,8 +20,8 @@
 #include "SkString.h"
 #include "SkTArray.h"
 #include "SkTDArray.h"
+#include "SkTaskGroup.h"
 #include "SkTemplates.h"
-#include "SkThreadPool.h"
 #include "SkTime.h"
 
 __SK_FORCE_IMAGE_DECODER_LINKING;
@@ -90,14 +90,14 @@ static SkString get_in_path(int dirNo, const char* filename) {
     }
     if (filename) {
         path.appendf("%s%s", PATH_SLASH, filename);
-        if (!sk_exists(path.c_str())) {        
+        if (!sk_exists(path.c_str())) {
             SkDebugf("could not read %s\n", path.c_str());
             return SkString();
         }
     }
     return path;
 }
-    
+
 static void make_recursive_dir(const SkString& path) {
     if (sk_exists(path.c_str())) {
         return;
@@ -129,7 +129,7 @@ static SkString get_out_path(int dirNo, const char* dirName) {
     make_recursive_dir(path);
     return path;
 }
-  
+
 static SkString get_sum_path(const char* dirName) {
     SkString path;
     SkASSERT(dirName);
@@ -166,12 +166,12 @@ struct TestResult {
         fTestStep = kCompareBits;
         fScale = 1;
     }
-    
+
     void init(int dirNo, const SkString& filename) {
         fDirNo = dirNo;
         strcpy(fFilename, filename.c_str());
         fTestStep = kCompareBits;
-        fScale = 1;       
+        fScale = 1;
     }
 
     SkString status() {
@@ -204,7 +204,7 @@ struct TestResult {
     }
 
     void testOne();
-    
+
     char fFilename[kMaxLength];
     TestStep fTestStep;
     int fDirNo;
@@ -245,13 +245,8 @@ struct TestState {
 };
 
 struct TestRunner {
-    TestRunner(int threadCount)
-        : fNumThreads(threadCount) {
-    }
-
     ~TestRunner();
     void render();
-    int fNumThreads;
     SkTDArray<class TestRunnable*> fRunnables;
 };
 
@@ -300,9 +295,9 @@ TestRunner::~TestRunner() {
 }
 
 void TestRunner::render() {
-    SkThreadPool pool(fNumThreads);
+    SkTaskGroup tg;
     for (int index = 0; index < fRunnables.count(); ++ index) {
-        pool.add(fRunnables[index]);
+        tg.add(fRunnables[index]);
     }
 }
 
@@ -531,18 +526,12 @@ DEFINE_string2(dir, d, NULL, "range of directories (e.g., 1-100)");
 DEFINE_string2(skp, s, NULL, "skp to test");
 DEFINE_bool2(single, z, false, "run tests on a single thread internally.");
 DEFINE_int32(testIndex, 0, "override local test index (PathOpsSkpClipOneOff only).");
-DEFINE_int32(threads, SkThreadPool::kThreadPerCore,
-        "Run threadsafe tests on a threadpool with this many threads.");
 DEFINE_bool2(verbose, v, false, "enable verbose output.");
 
 static bool verbose() {
     return FLAGS_verbose;
 }
 
-static int getThreadCount() {
-    return FLAGS_single ? 1 : FLAGS_threads;
-}
-
 class Dirs {
 public:
     Dirs() {
@@ -616,7 +605,7 @@ public:
         }
         return NULL;
     }
-    
+
     void set(const SkCommandLineFlags::StringArray& names) {
         fNames = &names;
     }
@@ -626,7 +615,7 @@ private:
     const SkCommandLineFlags::StringArray* fNames;
 } gNames;
 
-static bool buildTestDir(int dirNo, int firstDirNo, 
+static bool buildTestDir(int dirNo, int firstDirNo,
         SkTDArray<TestResult>* tests, SkTDArray<SortByName*>* sorted) {
     SkString dirName = get_out_path(dirNo, outStatusDir);
     if (!dirName.size()) {
@@ -792,8 +781,7 @@ static void encodeFound(TestState& state) {
             }
         }
     }
-    int threadCount = getThreadCount();
-    TestRunner testRunner(threadCount);
+    TestRunner testRunner;
     for (int index = 0; index < state.fPixelWorst.count(); ++index) {
         const TestResult& result = state.fPixelWorst[index];
         SkString filename(result.fFilename);
@@ -865,8 +853,7 @@ static void testSkpClipMain(TestState* data) {
 DEF_TEST(PathOpsSkpClipThreaded) {
     gDirs.setDefault();
     initTest();
-    int threadCount = getThreadCount();
-    TestRunner testRunner(threadCount);
+    TestRunner testRunner;
     int dirNo;
     gDirs.reset();
     while ((dirNo = gDirs.next()) > 0) {
@@ -889,7 +876,7 @@ DEF_TEST(PathOpsSkpClipThreaded) {
     }
     encodeFound(state);
 }
- 
+
 static bool buildTests(SkTDArray<TestResult>* tests, SkTDArray<SortByName*>* sorted) {
     int firstDirNo = gDirs.first();
     int dirNo;
@@ -912,8 +899,7 @@ DEF_TEST(PathOpsSkpClipUberThreaded) {
     if (!buildTests(tests.get(), sorted.get())) {
         return;
     }
-    int threadCount = getThreadCount();
-    TestRunner testRunner(threadCount);
+    TestRunner testRunner;
     int dirNo;
     gDirs.reset();
     while ((dirNo = gDirs.next()) > 0) {
diff --git a/tests/PathOpsThreadedCommon.cpp b/tests/PathOpsThreadedCommon.cpp
index ac4cd6ba62..0adde915e0 100644
--- a/tests/PathOpsThreadedCommon.cpp
+++ b/tests/PathOpsThreadedCommon.cpp
@@ -7,7 +7,7 @@
 
 #include "PathOpsExtendedTest.h"
 #include "PathOpsThreadedCommon.h"
-#include "SkThreadPool.h"
+#include "SkTaskGroup.h"
 
 PathOpsThreadedTestRunner::~PathOpsThreadedTestRunner() {
     for (int index = 0; index < fRunnables.count(); index++) {
@@ -16,8 +16,8 @@ PathOpsThreadedTestRunner::~PathOpsThreadedTestRunner() {
 }
 
 void PathOpsThreadedTestRunner::render() {
-    SkThreadPool pool(fNumThreads);
+    SkTaskGroup tg;
     for (int index = 0; index < fRunnables.count(); ++ index) {
-        pool.add(fRunnables[index]);
+        tg.add(fRunnables[index]);
     }
 }
diff --git a/tests/PathOpsThreadedCommon.h b/tests/PathOpsThreadedCommon.h
index a638cd2fdf..124921e389 100644
--- a/tests/PathOpsThreadedCommon.h
+++ b/tests/PathOpsThreadedCommon.h
@@ -33,17 +33,13 @@ struct PathOpsThreadState {
 
 class PathOpsThreadedTestRunner {
 public:
-    PathOpsThreadedTestRunner(skiatest::Reporter* reporter, int threadCount)
-        : fNumThreads(threadCount)
-        , fReporter(reporter) {
-    }
+    PathOpsThreadedTestRunner(skiatest::Reporter* reporter) : fReporter(reporter) {}
 
     ~PathOpsThreadedTestRunner();
 
     void render();
 
 public:
-    int fNumThreads;
     SkTDArray<PathOpsThreadedRunnable*> fRunnables;
     skiatest::Reporter* fReporter;
 };
diff --git a/tests/PathOpsTightBoundsTest.cpp b/tests/PathOpsTightBoundsTest.cpp
index 09f962296f..cea37520b1 100644
--- a/tests/PathOpsTightBoundsTest.cpp
+++ b/tests/PathOpsTightBoundsTest.cpp
@@ -35,8 +35,8 @@ static void testTightBoundsLines(PathOpsThreadState* data) {
 }
 
 DEF_TEST(PathOpsTightBoundsLines, reporter) {
-    int threadCount = initializeTests(reporter, "tightBoundsLines");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "tightBoundsLines");
+    PathOpsThreadedTestRunner testRunner(reporter);
     int outerCount = reporter->allowExtendedTest() ? 100 : 1;
     for (int index = 0; index < outerCount; ++index) {
         for (int idx2 = 0; idx2 < 10; ++idx2) {
@@ -110,8 +110,8 @@ static void testTightBoundsQuads(PathOpsThreadState* data) {
 }
 
 DEF_TEST(PathOpsTightBoundsQuads, reporter) {
-    int threadCount = initializeTests(reporter, "tightBoundsQuads");
-    PathOpsThreadedTestRunner testRunner(reporter, threadCount);
+    initializeTests(reporter, "tightBoundsQuads");
+    PathOpsThreadedTestRunner testRunner(reporter);
     int outerCount = reporter->allowExtendedTest() ? 100 : 1;
     for (int index = 0; index < outerCount; ++index) {
         for (int idx2 = 0; idx2 < 10; ++idx2) {
diff --git a/tests/SkpSkGrTest.cpp b/tests/SkpSkGrTest.cpp
index c1883a9890..c882654650 100644
--- a/tests/SkpSkGrTest.cpp
+++ b/tests/SkpSkGrTest.cpp
@@ -23,7 +23,7 @@
 #include "SkString.h"
 #include "SkTArray.h"
 #include "SkTDArray.h"
-#include "SkThreadPool.h"
+#include "SkTaskGroup.h"
 #include "SkTime.h"
 #include "Test.h"
 
@@ -125,14 +125,12 @@ struct SkpSkGrThreadState {
 };
 
 struct SkpSkGrThreadedTestRunner {
-    SkpSkGrThreadedTestRunner(skiatest::Reporter* reporter, int threadCount)
-        : fNumThreads(threadCount)
-        , fReporter(reporter) {
+    SkpSkGrThreadedTestRunner(skiatest::Reporter* reporter)
+        : fReporter(reporter) {
     }
 
     ~SkpSkGrThreadedTestRunner();
     void render();
-    int fNumThreads;
     SkTDArray<SkpSkGrThreadedRunnable*> fRunnables;
     skiatest::Reporter* fReporter;
 };
@@ -164,9 +162,9 @@ SkpSkGrThreadedTestRunner::~SkpSkGrThreadedTestRunner() {
 }
 
 void SkpSkGrThreadedTestRunner::render() {
-    SkThreadPool pool(fNumThreads);
+    SkTaskGroup tg;
     for (int index = 0; index < fRunnables.count(); ++ index) {
-        pool.add(fRunnables[index]);
+        tg.add(fRunnables[index]);
     }
 }
 
@@ -676,8 +674,7 @@ DEF_TEST(SkpSkGrThreaded, reporter) {
     if (!initTest()) {
         return;
     }
-    int threadCount = reporter->allowThreaded() ? 3 : 1;
-    SkpSkGrThreadedTestRunner testRunner(reporter, threadCount);
+    SkpSkGrThreadedTestRunner testRunner(reporter);
     for (int dirIndex = 1; dirIndex <= 100; ++dirIndex) {
         SkString pictDir = make_in_dir_name(dirIndex);
         if (pictDir.size() == 0) {
diff --git a/tests/Test.cpp b/tests/Test.cpp
index 20afd45561..d0147e1e4a 100644
--- a/tests/Test.cpp
+++ b/tests/Test.cpp
@@ -75,10 +75,6 @@ protected:
         return fReporter->allowExtendedTest();
     }
 
-    virtual bool allowThreaded() const SK_OVERRIDE {
-        return fReporter->allowThreaded();
-    }
-
     virtual void bumpTestCount() SK_OVERRIDE {
         fReporter->bumpTestCount();
     }
diff --git a/tests/Test.h b/tests/Test.h
index 72b0bee126..6c85b32bce 100644
--- a/tests/Test.h
+++ b/tests/Test.h
@@ -32,7 +32,6 @@ namespace skiatest {
         void endTest(Test*);
 
         virtual bool allowExtendedTest() const { return false; }
-        virtual bool allowThreaded() const { return false; }
         virtual bool verbose() const { return false; }
         virtual void bumpTestCount() { sk_atomic_inc(&fTestCount); }
 
diff --git a/tests/skia_test.cpp b/tests/skia_test.cpp
index 97ac29b0fd..0058215ccf 100644
--- a/tests/skia_test.cpp
+++ b/tests/skia_test.cpp
@@ -12,8 +12,8 @@
 #include "SkGraphics.h"
 #include "SkOSFile.h"
 #include "SkTArray.h"
+#include "SkTaskGroup.h"
 #include "SkTemplates.h"
-#include "SkThreadPool.h"
 #include "SkTime.h"
 #include "Test.h"
 
@@ -54,7 +54,6 @@ public:
     explicit DebugfReporter(int total) : fDone(0), fTotal(total) {}
 
     virtual bool allowExtendedTest() const SK_OVERRIDE { return FLAGS_extendedTest; }
-    virtual bool allowThreaded()     const SK_OVERRIDE { return !FLAGS_single; }
     virtual bool verbose()           const SK_OVERRIDE { return FLAGS_veryVerbose; }
 
 protected:
@@ -175,7 +174,8 @@ int test_main() {
     int32_t failCount = 0;
     int skipCount = 0;
 
-    SkThreadPool threadpool(FLAGS_threads);
+    SkTaskGroup::Enabler enabled(FLAGS_threads);
+    SkTaskGroup cpuTests;
     SkTArray<Test*> gpuTests;  // Always passes ownership to an SkTestRunnable
 
     DebugfReporter reporter(toRun);
@@ -186,7 +186,7 @@ int test_main() {
         } else if (test->isGPUTest()) {
             gpuTests.push_back() = test.detach();
         } else {
-            threadpool.add(SkNEW_ARGS(SkTestRunnable, (test.detach(), &failCount)));
+            cpuTests.add(SkNEW_ARGS(SkTestRunnable, (test.detach(), &failCount)));
         }
     }
 
@@ -204,7 +204,7 @@ int test_main() {
     }
 
     // Block until threaded tests finish.
-    threadpool.wait();
+    cpuTests.wait();
 
     if (FLAGS_verbose) {
         SkDebugf("\nFinished %d tests, %d failures, %d skipped. (%d internal tests)",