Updates here:
Devices exposing the issue so far (output 160):
Meizu M2 Note; CPU Mediatek MT6753; Android 5.1; Root: NO
Doogee Leo DG280; CPU Mediatek MT6582; Android 4.4.2; Root: NO
============
I have a really weird behavior of a while loop happening on a DooGee Leo LG280.
The output of this loop is 60 on every emulator and phone that I've tested. I can run it 100 times and the result will always be 60.
The code:
public class JavaActivity extends AppCompatActivity {
#Override public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int limitValue = 50;
int result = startWeirdLoop(limitValue);
System.out.println("my weird loop in java " + result);
((TextView)findViewById(R.id.textView)).setText(String.valueOf(result));
}
private int startWeirdLoop(int limitValue) {
int index = 0;
while (index <= limitValue) {
index += 20;
}
return index;
}
}
If you run the same code on the devices listed above, the output is 160.
To let it output the right value (60) there are some things I tried so far:
just add an empty print statement in the loop
hardcode the limitValue in the while by replacing it with 50.
replace Integer to int in the parameter limitValue
flip the condition in the while: while (limitValue >= index)
add 0 to limitValue: while (index <= limitValue + 0)
It really doesn't make sense to me! Why a System.out.println("") should magically fix the result of a while loop? Why hardcoding the parameter should fix it as well? And most importantly, why is this happening only on this device?
It seems that any instruction added into the loop makes the loop work as expected. And this scares me.
Could it be related to the CPU (MediaTek MT6582 ARM Cortex-A7)? To the system version? I don't know but this really pisses me off, because it's happening only on this device and I'm scared it could be on others. I repeat, on emulators and Huawey, LG, Samsung devices works fine.
My only doubt here is somehow related to combination CPU <-> Android Runtime ART. If you have this model of phone or another phone with MT6582, please try to run this code.
Screenshots:
Instrumented test run on the DooGee device (to avoid any layout related issues)
Related
I upgraded my Samsung Galaxy S4 from latest KitKat to Lollipop (5.0.1) yesterday and my IR remote control app that I have used for months stopped working.
Since I was using a late copy of KitKat ConsumerIrManager, the transmit( ) function was sending the number of pulses using the code below. It worked very nicely.
private void irSend(int freqHz, int[] pulseTrainInMicroS) {
int [] pulseCounts = new int [pulseTrainInMicroS.length];
for (int i=0; i<pulseTrainInMicroS.length; i++) {
long iValue = pulseTrainInMicroS[i] * freqHz / 1000000;
pulseCounts[i] = (int) iValue;
}
m_IRService.transmit(freqHz, pulseCounts);
}
when it stopped working yesterday, I began looking closely at it.
I noticed that the transmitted waveform is not having any relationship with the requested pulse train. even the code below doesn't work correctly! there is
private void TestSend() {
int [] pulseCounts = {100, 100, 100};
m_IRService.transmit(38000, pulseCounts);
}
the resulting waveforms had many problems and so are entirely useless.
the waveforms were entirely wrong
the frequency was wrong and the pulse spacing was not regular
they were not repeatable
looking at the demodulated waveform:
if my 100, 100, 100 were correctly rendered, I should have seen two pulses 2.6ms (before 4.4.3(?) 100 us) long. instead I received (see attached) "[demodulated] not repeatable 1.BMP" and "[demodulated] not repeatable 2.BMP". note that the waveform isn't 2 pulses...in fact, it's not even repeatable.
as for the captures below, the signal goes low when the IR is detected.
we should have seen two pulses going low for 2.6 ms and 2.6 ms between them (see green line below).
I had also tried shorter pulses using 50, 50, 50 and have observed that the first pulse isn't correct either (see below).
looking at the modulated waveform:
the frequency was not correct; instead, it was about 18kHz and irregular.
I'm quite experienced with this and have formal education in electronics.
It seems to me there's a bug in ConsumerIrManager.transmit( )...
curiously, the "WatchOn" application that comes with the phone still works.
thank you for any insights you can give.
Test equipment:
Tektronix TDS-2014B, 100 MHz, used in peak-detect mode.
As #IvanTellez says, a change was made in Android in respect to this functionality. Strangely, when I had it outputting simple IR signals (for troubleshooting purposes), the function behaves as shown above (erratically, wrong carrier frequency, etc). When I eventually returned to normal types of IR signals, it worked correctly.
I am trying to set the Performance Monitor User Mode Enable register on all cpus on a Nexus 4 running a mako kernel.
Right now I am setting the registers in a loadable module:
void enable_registers(void* info)
{
unsigned int set = 1;
/* enable user-mode access to the performance counter*/
asm volatile ("mcr p15, 0, %0, c9, c14, 0\n\t" : : "r" (set));
}
int init_module(void)
{
online = num_online_cpus();
possible = num_possible_cpus();
present = num_present_cpus();
printk (KERN_INFO "Online Cpus=%d\nPossible Cpus=%d\nPresent Cpus=%d\n", online, possible, present);
on_each_cpu(enable_registers , NULL, 1);
return 0;
}
The problem is that on_each_cpu only runs the function on Online cpus and as shown by the printk statment:
Online Cpus=1
Possible Cpus=4
Present Cpus=4
Only one of the four is online when I call on_each_cpu. So my question is, how do I force a cpu to be online, or how can force a certain cpu to execute code?
Thanks
You don't need to run the code on every cpu right now. What you need to do is arrange so that when the offline cpus come back online, your code is able to execute and enable the access to the PMU.
One way to achieve that would be with a cpu hotplug notifier.
My app targets version 2.2 and seems to run fine on the 3 devices I've tested it on (version 2.2 and 2.3)
However, I just ran it on a Google Nexus 10 tablet and the splash screen works OK and takes a touch input to start the next activity (a menu system based off of SurfaceView using multiple threads) and although it displays / animates OK, none of the buttons are working - I'm not really sure where to begin, am I wrong in assuming apps written for older Android API's are not compatible with newer releases of the OS? Surely newer versions are backwardly compatible?
Thanks all!!
Edit: If I repeatedly hit the start button, Logcat is showing this:
So not sure why this is doing this on JB but OK on devices running older OS's - thank you all.
Edit 2:
Code for 'button' release (after 'button' press):
if (event.getAction()==MotionEvent.ACTION_UP){
Intent StartNewGame = new Intent((Activity) getContext(), StartGame.class);
getContext().startActivity(StartGame);
// Oddly, if I put a System.exit(0); here, game activity starts and everything is fine - obviously this is only for testing and needs to be removed.
return true;}
}
public int nextInt(int n) {
if (n > 0) {
if ((n & -n) == n) {
return (int) ((n * (long) next(31)) >> 31);
}
int bits, val;
do {
bits = next(31);
val = bits % n;
} while (bits - val + (n - 1) < 0);
return val;
}
throw new IllegalArgumentException();
}
That is the code from the source for 4.1 so it looks like you are some how passing a 0 to the function , is there any way this could happen in your code?
So i overclocked my phone to 1.664ghz and I know there are apps that test your phone's CPU performance and stressers but I would like to make my own someway. What is the best way to really make your CPU work? I was thinking just making a for loop do 1 million iterations of doing some time-consuming math...but that did not work becuase my phone did it in a few milliseconds i think...i tried trillions of iterations...the app froze but my task manager did not show the cpu even being used by the app. Usually stress test apps show up as red and say cpu:85% ram: 10mb ...So how can i really make my processor seriously think?
To compile a regex string:
Pattern p1 = Pattern.compile("a*b"); // a simple regex
// slightly more complex regex: an attempt at validating email addresses
Pattern p2 = Pattern.compile("[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*#(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+(?:[A-Z]{2}|com|org|net|edu|gov|mil|biz|info|mobi|name|aero|asia|jobs|museum)\b");
You need to launch these in background threads:
class RegexThread extends Thread {
RegexThread() {
// Create a new, second thread
super("Regex Thread");
start(); // Start the thread
}
// This is the entry point for the second thread.
public void run() {
while(true) {
Pattern p = Pattern.compile("[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*#(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+(?:[A-Z]{2}|com|org|net|edu|gov|mil|biz|info|mobi|name|aero|asia|jobs|museum)\b");
}
}
}
class CPUStresser {
public static void main(String args[]) {
static int NUM_THREADS = 10, RUNNING_TIME = 120; // run 10 threads for 120s
for(int i = 0; i < NUM_THREADS; ++i) {
new RegexThread(); // create a new thread
}
Thread.sleep(1000 * RUNNING_TIME);
}
}
(above code appropriated from here)
See how that goes.
I would suggest a slightly different test, it is not a simple mathematical algorithms and functions. There are plenty of odd-looking tests whose results always contains all reviews. You launch the application, it works for a while, and then gives you the result in standard scores. The more points more (or less), it is considered that the device better. But that the comparison results mean in real life, is not always clear. And not all.
Regard to mathematics, the first thing that comes to mind is a massive amount of counting decimal places and the task to count the number "pi"
OK. No problem, we will do it:
Here's a test number one - "The Number Pi" - how long it takes your phone to calculate the ten million digits of Pi (3.14) (if someone said this phrase a hundred years ago, exactly would be immediately went to a psychiatric hospital)
When you feel that the phone is slow. You turn / twist interface. But how to measure it - it is unclear.
Angry Birds run on different devices at different times - perhaps test "Angry Birds"
We think further - get a couple more tests, "heavy book" and "a large page."
algorithm of calculation:
Test "of Pi"
Take the Speed Pi.
Count ten million marks by using a slow algorithm "Abraham Sharp Series. Repeat measurements several times, take the average.
Test "Angry Birds"
Take the very first Angry Birds (not required, but these versions are not the most optimized)
Measure the time from launch to the first sounds of music. Exit. Immediately run over and over again. Repeat several times and take the average.
Test "Large Page"
Measure the load time of heavy site pages. You can do it with your favorite browser :)
You can use This link (sorry for the Cyrillic)
This page is maintained by using "computers browser" along with pictures. Total turns out 6.5 Mb and 99 files (I'm still on this page in its stored version of a small sound file)
All 99 files upload to the phone. Turn off Wi-Fi and mobile Internet (this is important!)
Page opens with your browser. Click the "back" button. And now click "Forward" and measure the time the page is fully loaded. And so a few times. Back-forward, backward-forward. As usual, we take the average.
All results are given in seconds.
During testing all devices that support microSD cards, was one and the same card-Transcend 16 Gb, class 10. And all data on it.
Well, the actual results of the tests for some devices TEST RESULT
https://play.google.com/store/apps/details?id=xcom.saplin.xOPS - the app crunches numbers (integer and float) on multiple threads (2x number of cores) and builds performance and CPU temperature graphs.
https://github.com/maxim-saplin/xOPS-Console/blob/master/Saplin.xOPS/Compute.cs - that's the core of the app
I developed an auto-call application. The app reads a text file that includes a phone number list and calls for a few second, ends the call and then repeats.
My problem is that the app does not send calls after 10~16 hours. I don't know the reason exactly, but I guess that the problem is the CPU usage. My app's CPU usage is almost 50%! How do I reduce CPU usage?
Here is part of source code:
if(r_count.compareTo("0")!=0) {
while(index < repeat_count) {
count = 1;
time_count = 2;
while(count < map.length) {
performDial(); //start call
reject(); //end call
finishActivity(1);
TimeDelay("60"); // wait for 60sec
count = count + 2;
time_count = time_count + 2;
onBackPressed(); // press back button for calling next number
showCallLog();
finishActivity(0);
}
index++;
}
This is the TimeDelay() method source:
public void TimeDelay(String delayTime) {
saveTime = System.currentTimeMillis()/1000;
currentTime = 0;
dTime = Integer.parseInt(delayTime);
while(currentTime - saveTime < dTime) {
currentTime = System.currentTimeMillis()/1000;
}
}
TimeDelay() repeats in the while loop for a few times.
The reason it's using 50% of your CPU is that Android apparently won't let it use 100% of the CPU, which a loop like the one in your TimeDelay() ordinarily would. (Or else you have two CPUs and it is in fact using 100% of one CPU.) What you're doing is called a busy wait and it should be obvious why continually checking a condition will use lots of CPU. So don't do that. Use Thread.sleep() instead. Your app will then use no CPU at all during the wait.
Also, for God's sake, why are you passing a string and then parseInting it, rather than just passing an Integer in the first place? :-)
If your method take a long time to finish , especially the while loop. You should put Thread.sleep(50) inside your loop. This makes you processor be able to handle other processes.
Your CPU will be reduced. Not sure but you should try.
Hope you get good result.