Reenable multiple syncthreads

Prior, enabling multiple syncthreads caused a stream of
eglClientWaitSync errors. SyncThread::initSyncContext was only telling a
single worker thread to SYNC_THREAD_INIT. Other workers weren't
initializing their EGL contexts, so on those threads invoking
FenceSync::wait would fail in the GT_CTX_V2_RET of GLESv30Imp.cpp's
internal_glClientWaitSync because of a lack of thread context, returning
GL_WAIT_FAILED (without setting the last error!).

As a minimal workaround, this change dispatches a command for each
worker in the pool, which works because the underlying job-assignment
strategy for worker thread commands is round-robin.

Additionally, amends the abnormal exit error log with eglGetError().

Bug: 186146855
Test: Verify no more nonstop abnormal exit errors.
Change-Id: I2c8772b20551a863a262bc6ebc12028a959808fe

2 files changed, 12 insertions, 6 deletions

diff --git a/base/ThreadPool.h b/base/ThreadPool.h
index ceacd10e..f21a628d 100644
--- a/base/ThreadPool.h
+++ b/base/ThreadPool.h
@@ -121,6 +121,7 @@ public:
 
     void enqueue(Item&& item) {
         // Iterate over the worker threads until we find a one that's running.
+        // TODO(b/187082169, warty): We rely on this round-robin strategy in SyncThread
         for (;;) {
             int currentIndex =
                     mNextWorkerIndex.fetch_add(1, std::memory_order_relaxed);
diff --git a/stream-servers/SyncThread.cpp b/stream-servers/SyncThread.cpp
index 1b3e0e74..f0744294 100644
--- a/stream-servers/SyncThread.cpp
+++ b/stream-servers/SyncThread.cpp
@@ -66,7 +66,7 @@ static GlobalSyncThread* sGlobalSyncThread() {
 
 static const uint32_t kTimelineInterval = 1;
 static const uint64_t kDefaultTimeoutNsecs = 5ULL * 1000ULL * 1000ULL * 1000ULL;
-static const uint64_t kNumWorkerThreads = 1u;
+static const uint64_t kNumWorkerThreads = 4u;
 
 SyncThread::SyncThread()
     : android::base::Thread(android::base::ThreadFlags::MaskSignals, 512 * 1024),
@@ -132,9 +132,13 @@ void SyncThread::cleanup() {
 
 void SyncThread::initSyncContext() {
     DPRINT("enter");
-    SyncThreadCmd to_send;
-    to_send.opCode = SYNC_THREAD_INIT;
-    sendAndWaitForResult(to_send);
+    // TODO(b/187082169, warty): The thread pool's command-assignment strategy
+    // is round-robin, so as a hack, create one command for each worker.
+    for (int i = 0; i < mWorkerThreadPool.numWorkers(); i++) {
+        SyncThreadCmd to_send;
+        to_send.opCode = SYNC_THREAD_INIT;
+        sendAndWaitForResult(to_send);
+    }
     DPRINT("exit");
 }
 
@@ -313,8 +317,9 @@ void SyncThread::doSyncBlockedWaitNoTimeline(SyncThreadCmd* cmd) {
            wait_result);
 
     if (wait_result != EGL_CONDITION_SATISFIED_KHR) {
-        fprintf(stderr, "error: eglClientWaitSync abnormal exit 0x%x %p\n",
-                wait_result, cmd->fenceSync);
+        EGLint error = s_egl.eglGetError();
+        fprintf(stderr, "error: eglClientWaitSync abnormal exit 0x%x %p %#x\n",
+                wait_result, cmd->fenceSync, error);
     }
 }