commit 8b3f315e7a85989b200b8678f6d82ae45ad5c810
author Philip Cuadra <philipcuadra@google.com> Thu Apr 20 16:02:48 2017 -0700
committer Philip Cuadra <philipcuadra@google.com> Tue Apr 25 16:15:40 2017 -0700
tree 70bbea385389f87415c38701f3a9a07b6161974f
parent 12d67e3c7a9b8caaf2ec4d74598aca9f35405e84

Make BT HAL audio threads RT

Bluetooth threads that are used in audio have deadline
requirements for glitchless playback.  Those threads need to be
scheduled as RT tasks to ensure that they can meet the deadline even if
there is high system load.  Use schedulerservice to request RT
scheduling.

Bug 37518404
Test:  play Bluetooth audio, check for RT with systrace
Change-Id: I043a97df3d2801922b54dcbf7c700ae11a48c217

bluetooth/1.0/default/Android.bp

diff --git a/bluetooth/1.0/default/Android.bp b/bluetooth/1.0/default/Android.bp
index fec2264..46a4987 100644
--- a/bluetooth/1.0/default/Android.bp
+++ b/bluetooth/1.0/default/Android.bp
@@ -24,6 +24,7 @@
         "vendor_interface.cc",
     ],
     shared_libs: [
+        "android.frameworks.schedulerservice@1.0",
         "android.hardware.bluetooth@1.0",
         "libbase",
         "libcutils",
@@ -48,6 +49,7 @@
     ],
     export_include_dirs: ["."],
     shared_libs: [
+        "android.frameworks.schedulerservice@1.0",
         "liblog",
     ],
 }
@@ -84,9 +86,11 @@
         "test",
     ],
     shared_libs: [
+        "android.frameworks.schedulerservice@1.0",
         "libbase",
         "libhidlbase",
         "liblog",
+        "libutils",
     ],
     static_libs: [
         "android.hardware.bluetooth-async",

bluetooth/1.0/default/Android.mk

diff --git a/bluetooth/1.0/default/Android.mk b/bluetooth/1.0/default/Android.mk
index 38294c7..2dcb067 100644
--- a/bluetooth/1.0/default/Android.mk
+++ b/bluetooth/1.0/default/Android.mk
@@ -35,5 +35,6 @@
   libhidlbase \
   libhidltransport \
   android.hardware.bluetooth@1.0 \
+  android.frameworks.schedulerservice@1.0\
 
 include $(BUILD_EXECUTABLE)

bluetooth/1.0/default/async_fd_watcher.cc

diff --git a/bluetooth/1.0/default/async_fd_watcher.cc b/bluetooth/1.0/default/async_fd_watcher.cc
index 05ac537..ab8d555 100644
--- a/bluetooth/1.0/default/async_fd_watcher.cc
+++ b/bluetooth/1.0/default/async_fd_watcher.cc
@@ -14,6 +14,8 @@
 // limitations under the License.
 //
 
+#define LOG_TAG "android.hardware.bluetooth@1.0-impl"
+
 #include "async_fd_watcher.h"
 
 #include <algorithm>
@@ -22,13 +24,18 @@
 #include <map>
 #include <mutex>
 #include <thread>
+#include <utils/Log.h>
 #include <vector>
 #include "fcntl.h"
 #include "sys/select.h"
 #include "unistd.h"
 
+#include <android/frameworks/schedulerservice/1.0/ISchedulingPolicyService.h>
+
 static const int INVALID_FD = -1;
 
+static const int BT_RT_PRIORITY = 1;
+
 namespace android {
 namespace hardware {
 namespace bluetooth {
@@ -112,6 +119,21 @@
 }
 
 void AsyncFdWatcher::ThreadRoutine() {
+  using ::android::frameworks::schedulerservice::V1_0::ISchedulingPolicyService;
+  using ::android::hardware::Return;
+  sp<ISchedulingPolicyService> manager = ISchedulingPolicyService::getService();
+  if (manager == nullptr) {
+    ALOGE("%s: Couldn't get scheduler manager to set SCHED_FIFO.", __func__);
+  } else {
+    Return<bool> ret = manager->requestPriority(getpid(),
+                                                gettid(),
+                                                BT_RT_PRIORITY);
+    if (!ret.isOk() || !ret) {
+      ALOGE("%s unable to set SCHED_FIFO for pid %d, tid %d", __func__,
+            getpid(), gettid());
+    }
+  }
+
   while (running_) {
     fd_set read_fds;
     FD_ZERO(&read_fds);