Android: Replace the java based tick timer implemented with a not as bloated and more accurate linux hrtimer based one. Further reduces idle cpu usage (0% on my phone but still 1-2% on a Samsung Galaxy S).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28784 a1c6a512-1295-4272-9138-f99709370657

android/src/org/rockbox/RockboxTimer.java

@@ -1,76 +0,0 @@
-/***************************************************************************
- *             __________               __   ___.
- *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
- *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
- *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
- *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
- *                     \/            \/     \/    \/            \/
- * $Id$
- *
- * Copyright (C) 2010 Thomas Martitz
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- ****************************************************************************/
-
-package org.rockbox;
-
-import java.util.Timer;
-import java.util.TimerTask;
-
-import android.content.Context;
-import android.util.Log;
-
-public class RockboxTimer extends Timer 
-{    
-    private class RockboxTimerTask extends TimerTask {
-        private RockboxTimer timer;
-        public RockboxTimerTask(RockboxTimer parent) 
-        {
-            super();
-            timer = parent;
-        }
-
-        @Override
-        public void run() 
-        {
-            timerTask();
-            synchronized(timer) { 
-                timer.notify(); 
-            }
-        }
-    }
-    
-    public RockboxTimer(Context c, long period_inverval_in_ms)
-    {
-        super("tick timer");
-        schedule(new RockboxTimerTask(this), 0, period_inverval_in_ms);
-    }
-
-    @SuppressWarnings("unused")
-    private void LOG(CharSequence text)
-    {
-        Log.d("Rockbox", (String) text);    
-    }
-
-
-    /* methods called from native, keep them simple */    
-    public void java_wait_for_interrupt()
-    {
-        synchronized(this) 
-        {
-            try {
-                this.wait();
-            } catch (InterruptedException e) {
-                /* Not an error: wakeup and return */
-            }
-        }
-    }
-    public native void timerTask();
-}

firmware/target/hosted/android/kernel-android.c

@@ -20,73 +20,83 @@
  ****************************************************************************/
 
 
-#include <jni.h>
+#include <time.h>
+#include <signal.h>
+#include <errno.h>
+#include <unistd.h>
+#include <semaphore.h>
 #include "config.h"
 #include "system.h"
 #include "button.h"
 #include "audio.h"
+#include "panic.h"
 
-extern JNIEnv *env_ptr;
 
-extern jobject RockboxService_instance;
+static sem_t wfi_sem;
-
-static jclass  RockboxTimer_class;
-static jobject RockboxTimer_instance;
-static jmethodID java_wait_for_interrupt;
-static bool    initialized = false;
 /*
- * This is called from the separate Timer java thread. I have not added any
+ * call tick tasks and wake the scheduler up */
- * interrupt simulation to it (like the sdl counterpart does),
+void timer_signal(int sig)
- * I think this is probably not needed, unless code calls disable_interrupt()
- * in order to be protected from tick tasks, but I can't remember a place right
- * now.
- *
- * No synchronisation mechanism either. This could possibly be problematic,
- * but we'll see :)
- */
-JNIEXPORT void JNICALL
-Java_org_rockbox_RockboxTimer_timerTask(JNIEnv *env, jobject this)
 {
-    (void)env;
+    (void)sig;
-    (void)this;
     call_tick_tasks();
+    interrupt();
 }
 
-void tick_start(unsigned int interval_in_ms)
+/*
-{
+ * wait on the sem which the signal handler posts to save cpu time (aka sleep)
-    JNIEnv e = *env_ptr;
+ *
-    /* first, create a new Timer instance */
+ * other mechanisms could use them as well */
-    RockboxTimer_class  = e->FindClass(env_ptr, "org/rockbox/RockboxTimer");
-    jmethodID constructor = e->GetMethodID(env_ptr,
-                                           RockboxTimer_class,
-                                           "<init>",
-                                           "(Landroid/content/Context;J)V");
-    /* the constructor will do the tick_start */
-    RockboxTimer_instance = e->NewObject(env_ptr,
-                                         RockboxTimer_class,
-                                         constructor,
-                                         RockboxService_instance,
-                                         (jlong)interval_in_ms);
-
-    /* get our wfi func also */
-    java_wait_for_interrupt = e->GetMethodID(env_ptr,
-                                             RockboxTimer_class,
-                                             "java_wait_for_interrupt",
-                                             "()V");
-    /* it's now safe to call java_wait_for_interrupt */
-    initialized = true;
-}
-
 void wait_for_interrupt(void)
 {
-    if (LIKELY(initialized))
+    sem_wait(&wfi_sem);
+}
+
+void interrupt(void)
 {
-        (*env_ptr)->CallVoidMethod(env_ptr,
+    int s;
-                                   RockboxTimer_instance,
+    /* unless idling, we usually have more interrupt() than wait_for_interrupt()
-                                   java_wait_for_interrupt);
+     * don't post unecessarily because wait_for_interrupt() would need to
+     * decrement for each wasted sem_post(), instead of sleeping directly */
+    sem_getvalue(&wfi_sem, &s);
+    if (s <= 0)
+        sem_post(&wfi_sem);
 }
+
+/*
+ * setup a hrtimer to send a signal to our process every tick */
+void tick_start(unsigned int interval_in_ms)
+{
+    int ret = 0;
+    sigset_t proc_set;
+    timer_t timerid;
+    struct itimerspec ts;
+    sigevent_t sigev = {
+        .sigev_notify = SIGEV_SIGNAL,
+        .sigev_signo  = SIGUSR2,
+    };
+
+    ts.it_value.tv_sec = ts.it_interval.tv_sec = 0;
+    ts.it_value.tv_nsec = ts.it_interval.tv_nsec = interval_in_ms*1000*1000;
+
+    /* add the signal handler */
+    signal(SIGUSR2, timer_signal);
+
+    /* add the timer */
+    ret |= timer_create(CLOCK_REALTIME, &sigev, &timerid);
+    ret |= timer_settime(timerid, 0, &ts, NULL);
+
+    /* unblock SIGUSR2 so the handler can run */
+    ret |= sigprocmask(0, NULL, &proc_set);
+    ret |= sigdelset(&proc_set, SIGUSR2);
+    ret |= sigprocmask(SIG_SETMASK, &proc_set, NULL);
+
+    ret |= sem_init(&wfi_sem, 0, 0);
+
+    if (ret != 0)
+        panicf("%s(): %s\n", __func__, strerror(errno));
 }
 
+
 bool timer_register(int reg_prio, void (*unregister_callback)(void),
                     long cycles, void (*timer_callback)(void))
 {

firmware/target/hosted/android/system-target.h

@@ -27,6 +27,8 @@
 #define restore_irq(level) (void)level
 
 void power_off(void);
+void wait_for_interrupt(void);
+void interrupt(void);
 
 #endif /* __SYSTEM_TARGET_H__ */
 

firmware/target/hosted/android/thread-android-arm.c

@@ -23,6 +23,7 @@
  ****************************************************************************/
 
 #include <jni.h>
+#include <system.h>
 /*---------------------------------------------------------------------------
  * Start the thread running and terminate it if it returns
  *---------------------------------------------------------------------------
@@ -89,7 +90,6 @@ static inline void load_context(const void* addr)
  * wait_for_interrupt is implemented in kernel-android.c
  **/
 
-extern void wait_for_interrupt(void);
 static inline void core_sleep(void)
 {
     wait_for_interrupt();