* `Self Time` is a *wall-clock time* spent in the method itself (**includes time waiting/sleeping**). 
* `Self Time (CPU)` is a time *processor time*, so it does **NOT include** time spent **waiting, sleeping**, etc. 
&lt;br&gt;
&lt;br&gt;
* Both columns do NOT include time spent in methods invoked from that method.
* Both `Self Time` and `Self Time (CPU)` in the sampler are *approximation* of actual data. 
* `Self Time [%]` refers to one of the two selected `Self Time [(CPU)]` columns. 

I am trying to show maps in android using API v2.&lt;br&gt;
I want UI some thing like this.But whenever **I try to add button in layout it does not reflect in output**&lt;br&gt;
**I am able to get maps without buttons**.&lt;br&gt;**I need buttons to integrate with map like below** &lt;br&gt;
code for Mylayout.xml:

	&lt;RelativeLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
    xmlns:tools=&quot;http://schemas.android.com/tools&quot;
    android:layout_width=&quot;match_parent&quot;
    android:layout_height=&quot;match_parent&quot;
    tools:context=&quot;.MapActivity&quot; &gt;
	&lt;RelativeLayout
	android:layout_width=&quot;match_parent&quot;
	android:layout_height=&quot;48dp&quot;&gt;
	&lt;LinearLayout 
    android:layout_width=&quot;match_parent&quot;
    android:layout_height=&quot;wrap_content&quot;
    android:orientation=&quot;horizontal&quot;&gt;
    &lt;RadioGroup 
    android:id=&quot;@+id/radio_group_list_selector&quot;
    android:layout_width=&quot;0dp&quot;
    android:layout_height=&quot;match_parent&quot;
    android:layout_gravity=&quot;center_horizontal|center_vertical&quot;
    android:gravity=&quot;center_horizontal&quot;
    android:orientation=&quot;horizontal&quot;
    android:layout_weight=&quot;1&quot;
    
    &gt;
    &lt;RadioButton
    android:id=&quot;@+id/radioPopular&quot;
    android:layout_width=&quot;0dp&quot;
    android:layout_height=&quot;match_parent&quot;
    android:gravity=&quot;center_horizontal|center_vertical&quot;
    android:text=&quot;@string/Popular&quot;
    android:layout_weight=&quot;1&quot;
    android:button=&quot;@null&quot;
    android:background=&quot;@drawable/shape_radiobutton&quot;
    android:layout_marginBottom=&quot;4dp&quot;
    android:layout_marginTop=&quot;4dp&quot;
    android:layout_marginLeft=&quot;4dp&quot;
    android:textColor=&quot;@drawable/textcolor_radiobutton&quot;
    
    /&gt;
    &lt;View
    android:id=&quot;@+id/VerticalLine&quot;
    android:layout_width=&quot;1dip&quot;
    android:layout_height=&quot;wrap_content&quot;
    android:layout_marginBottom=&quot;4dip&quot;
    android:layout_marginTop=&quot;4dip&quot;
    android:background=&quot;#aaa&quot;
     	 		/&gt;
    &lt;RadioButton
    android:id=&quot;@+id/radioAZ&quot;
    android:layout_width=&quot;0dp&quot;
    android:layout_height=&quot;match_parent&quot;
    android:gravity=&quot;center_horizontal|center_vertical&quot;
    android:text=&quot;@string/AZ&quot;
    android:layout_weight=&quot;1&quot;
    android:button=&quot;@null&quot;
    android:background=&quot;@drawable/shape_radiobutton2&quot;
    android:layout_marginBottom=&quot;4dp&quot;
    android:layout_marginTop=&quot;4dp&quot;
    android:textColor=&quot;@drawable/textcolor_radiobutton&quot;
    
    /&gt;
     &lt;View
    android:id=&quot;@+id/VerticalLine&quot;
    android:layout_width=&quot;1dip&quot;
    android:layout_height=&quot;wrap_content&quot;
    android:layout_marginBottom=&quot;4dip&quot;
    android:layout_marginTop=&quot;4dip&quot;
    android:background=&quot;#aaa&quot;
     	 		/&gt;
    &lt;RadioButton
    android:id=&quot;@+id/radioCategory&quot;
    android:layout_width=&quot;0dp&quot;
    android:layout_height=&quot;match_parent&quot;
    android:gravity=&quot;center_horizontal|center_vertical&quot;
    android:text=&quot;@string/Category&quot;
    android:layout_weight=&quot;1&quot;
    android:button=&quot;@null&quot;
    android:background=&quot;@drawable/shape_radiobutton2&quot;
    android:layout_marginBottom=&quot;4dp&quot;
    android:layout_marginTop=&quot;4dp&quot;
    android:textColor=&quot;@drawable/textcolor_radiobutton&quot;
    
    /&gt;
    &lt;View
    android:id=&quot;@+id/VerticalLine&quot;
    android:layout_width=&quot;1dip&quot;
    android:layout_height=&quot;wrap_content&quot;
    android:layout_marginBottom=&quot;4dip&quot;
    android:layout_marginTop=&quot;4dip&quot;
    android:background=&quot;#aaa&quot;
    /&gt;
     
    &lt;RadioButton
    android:id=&quot;@+id/radioNearBy&quot;
    android:layout_width=&quot;0dp&quot;
    android:layout_height=&quot;match_parent&quot;
    android:gravity=&quot;center_horizontal|center_vertical&quot;
    android:text=&quot;@string/NearBy&quot;
    android:layout_weight=&quot;1&quot;
    android:button=&quot;@null&quot;
    android:background=&quot;@drawable/shape_radiobutton3&quot;
    android:layout_marginBottom=&quot;4dp&quot;
    android:layout_marginTop=&quot;4dp&quot;
    android:layout_marginRight=&quot;4dp&quot;
    android:textColor=&quot;@drawable/textcolor_radiobutton&quot;
    /&gt;
    
    &lt;/RadioGroup&gt;
    
    &lt;/LinearLayout&gt;
    &lt;!-- For Horizontal Line--&gt;
    &lt;View
    android:layout_width=&quot;match_parent&quot;
    android:layout_height=&quot;1dip&quot;
    android:layout_marginLeft=&quot;4dip&quot;
    android:layout_marginRight=&quot;4dip&quot;
    android:background=&quot;#aaa&quot;
    android:layout_alignParentBottom=&quot;true&quot;/&gt;
    &lt;/RelativeLayout&gt;
	&lt;fragment xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
    xmlns:map=&quot;http://schemas.android.com/apk/res-auto&quot;
    android:id=&quot;@+id/map&quot;
    android:layout_width=&quot;match_parent&quot;
    android:layout_height=&quot;wrap_content&quot;
    android:layout_weight=&quot;1&quot;
    android:scrollbars=&quot;vertical&quot;  
    class=&quot;com.google.android.gms.maps.SupportMapFragment&quot;/&gt;
	&lt;/RelativeLayout&gt;


![Maps with Button][1]


  [1]: http://i.stack.imgur.com/kkJrT.png

How to add buttons at top of map fragment API v2 layout

I am working on an opengl project. 
I have used some images (2 for x-y scales) and labels (8) to display the scale on the screen. 
My first view is a `tableview` from which I go to `openglView`. But whenever I go back from `openglView` to the `tableView` it gives me this error and app crashes. 

**&quot;This UIView seems to be the delegate of an NSISVariable it doesn&#39;t know anything about. This is an internal UIKit bug.&quot;**

ANY Suggestions?
Is this happening because I am including too many UI elements, other than those images and labels I have used some buttons also. And I am applying `affineTransform` to those images and labels and one button also.


**Exact error is:**

    2013-01-31 12:20:18.743 EMtouch[50496:12203] *** Terminating app due to uncaught exception &#39;NSInternalInconsistencyException&#39;, reason: &#39;{ Rows:
    	UILayoutContainerView:0x9835660.Height == 480 + 1*0x7e53030.marker + 1*0x7e546c0.marker
    	UILayoutContainerView:0x9835660.Width == 320 + 1*0x7e52f90.marker + 1*0x7e54330.marker
    	UILayoutContainerView:0x9835660.minX == 0 + 1*0x7e52ca0.marker + -0.5*0x7e52f90.marker
    	UILayoutContainerView:0x9835660.minY == 0 + 1*0x7e52fd0.marker + -0.5*0x7e53030.marker
    	UINavigationTransitionView:0x9837ea0.Height == 480 + 1*0x7e51bf0.marker + 1*0x7e53030.marker + 1*0x7e546c0.marker
    	UINavigationTransitionView:0x9837ea0.Width == 320 + 1*0x7e519c0.marker + 1*0x7e52f90.marker + 1*0x7e54330.marker
    	UINavigationTransitionView:0x9837ea0.minX == 0 + 1*0x7e51940.marker + -0.5*0x7e519c0.marker
    	UINavigationTransitionView:0x9837ea0.minY == 0 + 1*0x7e51b80.marker + -0.5*0x7e51bf0.marker
    	UIWindow:0x7e1aea0.Height == 480 + 1*0x7e546c0.marker
    	UIWindow:0x7e1aea0.Width == 320 + 1*0x7e54330.marker
    	UIWindow:0x7e1aea0.minX == 0 + -0.5*0x7e54330.marker + 1*0x7e54410.marker
    	UIWindow:0x7e1aea0.minY == 0 + 1*0x7e542d0.marker + -0.5*0x7e546c0.marker
    	objective == &lt;250:-0.000579834&gt; + &lt;250:-9.72015e-08&gt;*UILabel:0x7b44bf0.Width + &lt;250:9.72015e-08&gt;*UILabel:0x7b45100.Width
    
      Constraints:
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e51940 h=-&amp;- v=-&amp;- UINavigationTransitionView:0x9837ea0.midX == UILayoutContainerView:0x9835660.midX&gt;		Marker:0x7e51940.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e519c0 h=-&amp;- v=-&amp;- UINavigationTransitionView:0x9837ea0.width == UILayoutContainerView:0x9835660.width&gt;		Marker:0x7e519c0.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e51b80 h=-&amp;- v=-&amp;- UINavigationTransitionView:0x9837ea0.midY == UILayoutContainerView:0x9835660.midY&gt;		Marker:0x7e51b80.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e51bf0 h=-&amp;- v=-&amp;- UINavigationTransitionView:0x9837ea0.height == UILayoutContainerView:0x9835660.height&gt;		Marker:0x7e51bf0.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e52ca0 h=-&amp;- v=-&amp;- UILayoutContainerView:0x9835660.midX == UIWindow:0x7e1aea0.midX&gt;		Marker:0x7e52ca0.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e52f90 h=-&amp;- v=-&amp;- UILayoutContainerView:0x9835660.width == UIWindow:0x7e1aea0.width&gt;		Marker:0x7e52f90.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e52fd0 h=-&amp;- v=-&amp;- UILayoutContainerView:0x9835660.midY == UIWindow:0x7e1aea0.midY&gt;		Marker:0x7e52fd0.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e53030 h=-&amp;- v=-&amp;- UILayoutContainerView:0x9835660.height == UIWindow:0x7e1aea0.height&gt;		Marker:0x7e53030.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e54330 h=--- v=--- H:[UIWindow:0x7e1aea0(320)]&gt;		Marker:0x7e54330.marker
    	&lt;NSAutoresizingMaskLayoutConstraint:0x7e546c0 h=--- v=--- V:[UIWindow:0x7e1aea0(480)]&gt;		Marker:0x7e546c0.marker
    	&lt;_UIWindowAnchoringConstraint:0x7e542d0 h=--- v=--- UIWindow:0x7e1aea0.midY == + 240&gt;		Marker:0x7e542d0.marker
    	&lt;_UIWindowAnchoringConstraint:0x7e54410 h=--- v=--- UIWindow:0x7e1aea0.midX == + 160&gt;		Marker:0x7e54410.marker
    }: internal error.  Cannot find an outgoing row head for incoming head UILabel:0x7b44bf0.Width, which should never happen.&#39;
    *** First throw call stack:
    (0x1fb1012 0x19f4e7e 0x1fb0deb 0x1599609 0x159c64f 0x159c753 0xe7e8f9 0x982b24 0x982783 0xbba3fe 0xbba698 0x97a3b6 0x97a554 0x28f7d8 0x1c2b014 0x1c1b7d5 0x1f57af5 0x1f56f44 0x1f56e1b 0x34d37e3 0x34d3668 0x93c65c 0xc56d 0x2b35 0x1)
    libc++abi.dylib: terminate called throwing an exception



&quot;This UIView seems to be the delegate of an NSISVariable it doesn&#39;t know anything about. This is an internal UIKit bug&quot; Error

I&#39;ve been searching all over for a consistent and clear explanation of what &#39;self time&#39; actually refers to in the VisualVM context and how does it differ to &#39;self time (cpu)&#39;. Also does &#39;self time [%]&#39; refer to self time or self time cpu. 

There doesn&#39;t appear to be much documentation on this or at least I haven&#39;t found it. So any thoughts/input will be appreciated.

VisualVM and Self Time

<p>I've been searching all over for a consistent and clear explanation of what 'self time' actually refers to in the VisualVM context and how does it differ to 'self time (cpu)'. Also does 'self time [%]' refer to self time or self time cpu.</p>
<p>There doesn't appear to be much documentation on this or at least I haven't found it. So any thoughts/input will be appreciated.</p>


Currently I have this :

    @Scheduled(fixedRate=5000)
    public void getSchedule(){
       System.out.println(&quot;in scheduled job&quot;);
    }

I could change this to use a reference to a property

    @Scheduled(fixedRateString=&quot;${myRate}&quot;)
    public void getSchedule(){
       System.out.println(&quot;in scheduled job&quot;);
    }

However I need to use a value obtained programmatically so the schedule can be changed without redeploying the app. What is the best way? I realize using annotations may not be possible... 

Scheduling a job with Spring programmatically (with fixedRate set dynamically)

I am trying to use the `org.springframework.orm.jdo.TransactionAwarePersistenceManagerFactoryProxy` in my Spring project, but I am not sure how to use it or whether it&#39;s exactly what I am looking for. I realize it can help make my DAOs work with a plain JDO `PersistenceManagerFactory`. Another question is: what happens if the proxy doesn&#39;t get made properly? Can I still use it to access my factory to create a transaction aware persistence manager? If the object managed by the factory is a singleton, does this change things? Why not just access the PersistenceManagerFactory directly? Perhaps `PersistenceManagerFactoryUtils.getPersistenceManager` would be more suited to my needs? Can `getObject` return null?

Unsure if I understand TransactionAwarePersistenceManagerFactoryProxy

Recently I started exploring Java 8 and I can&#39;t quite understand the concept of &quot;functional interface&quot; that is essential to Java&#39;s implementation of lambda expressions. There is a [pretty comprehensive guide][1] to lambda functions in Java, but I got stuck on [the chapter that gives definition to the concept of functional interfaces][2]. The definition reads:

&gt; More precisely, a functional interface is defined as any interface that has exactly one abstract method.

An then he proceeds to examples, one of which is `Comparator` interface:

&gt;     public interface Comparator&lt;T&gt; {
&gt;         int compare(T o1, T o2);
&gt;         boolean equals(Object obj);
&gt;     } 

I was able to test that I can use a lambda function in place of Comparator argument and it works(i.e. `Collections.sort(list, (a, b) -&gt; a-b)`). 

But in the Comparator interface both `compare` and `equals` methods are abstract, which means it has **two abstract methods**. So how can this be working, if the definition requires an interface to have **exactly one abstract method**? What am I missing here?


  [1]: http://www.lambdafaq.org/
  [2]: http://www.lambdafaq.org/what-is-a-functional-interface/

Precise definition of &quot;functional interface&quot; in Java 8

When upgrading from Surefire 2.6 to Surefire 2.13, I get a `TypeNotPresentExceptionProxy` when running my unit tests.

    java.lang.ArrayStoreException: sun.reflect.annotation.TypeNotPresentExceptionProxy
        at sun.reflect.annotation.AnnotationParser.parseClassArray(AnnotationParser.java:653)
        at sun.reflect.annotation.AnnotationParser.parseArray(AnnotationParser.java:460)
        at sun.reflect.annotation.AnnotationParser.parseMemberValue(AnnotationParser.java:286)
        at sun.reflect.annotation.AnnotationParser.parseAnnotation(AnnotationParser.java:222)
        at sun.reflect.annotation.AnnotationParser.parseAnnotations2(AnnotationParser.java:69)
        at sun.reflect.annotation.AnnotationParser.parseAnnotations(AnnotationParser.java:52)
        at java.lang.Class.initAnnotationsIfNecessary(Class.java:3070)
        at java.lang.Class.getAnnotation(Class.java:3029)
        at org.apache.maven.surefire.common.junit4.JUnit4TestChecker.isValidJUnit4Test(JUnit4TestChecker.java:64)

In `JUnit4TestChecker`, line 64 looks like this:

&lt;!-- language: lang-java --&gt;

    Annotation runWithAnnotation = testClass.getAnnotation( runWith );
    
So Surefire inspects the `@RunWith` annotation to make sure its type is valid. Our tests use Spring, so `@RunWith` looks like this in our test classes:

&lt;!-- language: lang-java --&gt;

    @RunWith(SpringJUnit4ClassRunner.class)

It seems like Surefire isn&#39;t finding the `SpringJUnit4ClassRunner` class. I&#39;m not sure why since under Surefire 2.6, the tests run fine.

Any ideas?

TypeNotPresentExceptionProxy

Can somebody explain this to me please :

    Intent intent = new Intent(Context, AlarmReceiver.class);

I never understood and I seriously think I never will if somebody doesn&#39;t try to explain this to me in depth. This whole context thing is so confusing to me. Sometimes it works like this :

		

    Intent intent = new Intent(getBaseContext(), AlarmReceiver.class);

Sometimes it wont work like that but it accepts only :

		Intent intent = new Intent(context, AlarmReceiver.class);

Sometimes its :

    Intent intent = new Intent(this, AlarmReceiver.class);

etc. etc. and many other.

I understand basics of context but how many are there? And why does eclipse throw me an error once and another time its fine? Why do we need to declare context sometimes? :

    Context context;

I&#39;m unable to find the right context for all situations how do I know what is the right one in every situation?

Android Intent Context Confusing

I asked Google to give me the meaning of the `gcc` option `-fomit-frame-pointer`, which redirects me to the below statement.


&gt; **-fomit-frame-pointer**
&gt;
&gt;  Don&#39;t keep the frame pointer in a register for functions that don&#39;t need one. This avoids the instructions to save, set up and restore frame pointers; it also makes an extra register available in many functions. It also makes debugging impossible on some machines.

As per my knowledge of each function, an activation record will be created in the stack of the process memory to keep all local variables and some more information. I hope this frame pointer means the address of the activation record of a function. 

In this case, what are the type of functions, for which it doesn&#39;t need to keep the frame pointer in a register? If I get this information, I will try to design the new function based on that (if possible) because if the frame pointer is not kept in registers, some instructions will be omitted in binary. This will really improve the performance noticeably in an application where there are many functions.

Trying to understand gcc option -fomit-frame-pointer

[OpenMP 4.0][1] introduces a new construct called &quot;omp simd&quot;. What is the benefit of using this construct over the old &quot;parallel for&quot;? When would each be a better choice over the other?

EDIT:
Here is an interesting [paper][2] related to the SIMD directive.


  [1]: http://www.openmp.org/mp-documents/OpenMP4.0RC1_final.pdf
  [2]: http://link.springer.com/content/pdf/10.1007/978-3-642-30961-8_5.pdf

Parallel for vs omp simd: when to use each?

I&#39;m currently starting on an animation project. In the project I&#39;ll have more than 40000 `div`s and animate them iteratively. If any of `div`s are in passive state (i.e. it&#39;s not animating at least for 2 seconds), I won&#39;t display them to increase animation performance.

The question is: which css property is the most suitable for this?
    
    .passive1{
       display:none
    }
    
    .passive2{
        visibility:hidden;
    }

    .passive3{
        opacity:0;
    }

And how can I measure rendering performance like fps, gpu usage?

visibility:hidden vs display:none vs opacity:0

Often in my inner loops I need to index an array in a &quot;wrap-around&quot; way, so that (for example) if the array size is 100 and my code asks for element -2, it should be given element 98. In many high level languages such as Python, one can do this simply with `my_array[index % array_size]`, but for some reason C&#39;s integer arithmetic (usually) rounds toward zero instead of consistently rounding down, and consequently its modulo operator returns a negative result when given a negative first argument.

Often I know that `index` will not be less than `-array_size`, and in these cases I just do `my_array[(index + array_size) % array_size]`. However, sometimes this can&#39;t be guaranteed, and for those cases I would like to know the fastest way to implement an always-positive modulo function. There are several &quot;clever&quot; ways to do it without branching, such as

    inline int positive_modulo(int i, int n) {
        return (n + (i % n)) % n;
    }

or 

    inline int positive_modulo(int i, int n) {
        return (i % n) + (n * (i &lt; 0));
    }

Of course I can profile these to find out which is the fastest on my system, but I can&#39;t help worrying that I might have missed a better one, or that what&#39;s fast on my machine might be slow on a different one.

So is there a standard way to do this, or some clever trick that I&#39;ve missed that&#39;s likely to be the fastest possible way?

Also, I know it&#39;s probably wishful thinking, but if there&#39;s a way of doing this that can be auto-vectorised, that would be amazing.


Fastest way to get a positive modulo in C/C++

In my PHP application I need to **read multiple lines starting from the end of 
many files** (mostly logs). Sometimes I need only the last one, sometimes I need 
tens or hundreds. Basically, I want something as flexible as the Unix `tail`
command.

There are questions here about how to get the single last line from a file (but
I need *N* lines), and different solutions were given. I&#39;m not sure about which 
one is the best and which performs better.

What is the best way to read last lines (i.e. &quot;tail&quot;) from a file using PHP?

I played with Visual Studio builtin profiling tools and now every time I check out any file this section automatically adds to my solution file:

    GlobalSection(Performance) = preSolution
        HasPerformanceSessions = true
    EndGlobalSection

I totally removed all profiling reports, then removed local copy of all source control files from this solution and update to latest. This section still in *.sln file after any checkout.

Other teammates who haven&#39;t used prfiler doesn&#39;t have this problem.
Has anyone any ideas?

How to force Visual Studio not to add GlobalSection(Performance) section?

I have a dataframe of the following form (for example)

    shopper_num,is_martian,number_of_items,count_pineapples,birth_country,tranpsortation_method
    1,FALSE,0,0,MX,
    2,FALSE,1,0,MX,
    3,FALSE,0,0,MX,
    4,FALSE,22,0,MX,
    5,FALSE,0,0,MX,
    6,FALSE,0,0,MX,
    7,FALSE,5,0,MX,
    8,FALSE,0,0,MX,
    9,FALSE,4,0,MX,
    10,FALSE,2,0,MX,
    11,FALSE,0,0,MX,
    12,FALSE,13,0,MX,
    13,FALSE,0,0,CA,
    14,FALSE,0,0,US,

How can I use Pandas to calculate summary statistics of each column (column data types are variable, some columns have no information 

And then return the a dataframe of the form:

    columnname, max, min, median,

    is_martian, NA, NA, FALSE

So on and so on


Calculate summary statistics of columns in dataframe

I want to find out how much time a certain function takes in my C++ program to execute on **Linux**. Afterwards, I want to make a speed comparison . I saw several time function but ended up with this from boost. Chrono:

    process_user_cpu_clock, captures user-CPU time spent by the current process

Now, I am not clear if I use the above function, will I get the only time which CPU spent on that function? 

Secondly, I could not find any example of using the above function. Can any one please help me how to use the above function?


P.S: Right now , I am using `std::chrono::system_clock::now()` to get time in seconds but this gives me different results due to different CPU load every time.

Measuring execution time of a function in C++

Recently switch to android studio from eclipse. How to check app heap and memory allocation in android studio? In Eclipse we have MAT is there anything in the studio to check heap dump, hprof file?

How to analyze memory using android studio

I am profiling the db queries in MongoDB. I followed [this][1] link. I am trying to delete all data from the collection system.profile so I can start benchmarking different queries again. I tried the following code but it gives an error

**CONSOLE SYNTAX**

    &gt; db.system.profile.remove({})

**ERROR**

    cannot delete from system namespace


  [1]: http://docs.mongodb.org/manual/reference/database-profiler/

How do I delete all data from that collection? If that&#39;s not possible, how can I start profiling from the beginning?

How to delete system.profile collection from a MongoDB?

I&#39;m confused on how many flops per cycle per core can be done with Sandy-Bridge and Haswell.
As I understand it with SSE it should be 4 flops per cycle per core for SSE and 8 flops per cycle per core for AVX/AVX2.  

This seems to be verified here,
https://stackoverflow.com/questions/8389648/how-to-achieve-4-flops-per-cycle
,and here,
https://stackoverflow.com/questions/12027922/sandy-bridge-cpu-specification.

However the link below seems to indicate that Sandy-bridge can do 16 flops per cycle per core and Haswell 32 flops per cycle per core
http://www.extremetech.com/computing/136219-intels-haswell-is-an-unprecedented-threat-to-nvidia-amd.

Can someone explain this to me?

Edit:
I understand now why I was confused.  I thought the term FLOP only referred  to single floating point (SP).  I see now that the test at https://stackoverflow.com/questions/8389648/how-to-achieve-4-flops-per-cycle are actually on double floating point (DP) so they achieve 4 DP FLOPs/cycle for SSE and 8 DP FLOPs/cycle for AVX.  It would be interesting to redo these test on SP.

FLOPS per cycle for sandy-bridge and haswell SSE2/AVX/AVX2

I mean: how can I measure time my CPU spent on function execution and wall clock time it takes to run my function? (Im interested in Linux/Windows and both x86 and x86_64). See what I want to do (Im using C++ here but I would prefer C solution):

    int startcputime, endcputime, wcts, wcte;
    
    startcputime = cputime();
    function(args);
    endcputime = cputime();
    
    std::cout &lt;&lt; &quot;it took &quot; &lt;&lt; endcputime - startcputime &lt;&lt; &quot; s of CPU to execute this\n&quot;;
    
    wcts = wallclocktime();
    function(args);
    wcte = wallclocktime();
    
    std::cout &lt;&lt; &quot;it took &quot; &lt;&lt; wcte - wcts &lt;&lt; &quot; s of real time to execute this\n&quot;;

**Another important question: is this type of time measuring architecture independent or not?**

How can I measure CPU time and wall clock time on both Linux/Windows?

From the 11th Chapter(*Performance and Scalability*) and the section named *Context Switching* of the [JCIP book][1]:

&gt; When a new thread is switched in, the data it needs is unlikely to be
&gt; in the local processor cache, so a context-switch causes a flurry of
&gt; cache misses, and thus threads run a little more slowly when they are
&gt; first scheduled.

 1. Can someone explain in an easy to understand way the concept of *cache miss* and its probable opposite (*cache hit*)?
 2. Why context-switching would cause a lot of cache miss?

[1]:http://jcip.net.s3-website-us-east-1.amazonaws.com/

What is a cache hit and a cache miss? Why would context-switching cause cache miss?

What is the difference between a core and a processor?

I&#39;ve already looked for it on Google, but I only get definitions for multi-core and multi-processor, which is not what I am looking for.


Difference between core and processor

The first time I ran Genymotion virtual device, it had worked. But when I tried running it today, I got this error message

![enter image description here][1]


  [1]: http://i.stack.imgur.com/s3lYt.png

What may have changed from the last time I used it? Will be grateful for any solutions that I can get. Thanks.

My Device Info:
Dell XPS L502X
Sandy Bridge motherboard
Intel Core i5-2410M @2.30 GHz
Windows 7 Professional 64-bit

Unable to start Genymotion virtual device, incompatible CPU

Other than the more &#39;advanced&#39; GUI from Java mission control, how are they different?

At first glance they seem to offer very similar functionality (Interpreting JMX data and Memory/CPU profiling).

However, as they are both shipped with the JDK (I&#39;m using JDK 1.7.0_51 SE) I&#39;m assuming there are significant differences, otherwise they would be combined into a single solution. Especially as this increases the size of the JDK significantly.

Is Java Mission Control ultimately going to replace JVisualVM in the future?

What are the differences between JVisualVM and Java Mission Control?

If I try to profile application, (which is prepared under Eclipse, but running from command line) with the help of VisualVM, I get the following error message

![enter image description here][1]

Simultaneously, the project folder is fouled with newly created class files. Although they are already existing in `target/classes`.

The project structure is Maven&#39;s, i.e. there is a foder `target/classes` in current directory and I us the following command to run the application

    java -Xmx16g -cp target/classes tests.Runner01

How to fix?

**UPDATE** 

The same occurs with conventional java project too.

Below it the picture of populated class files, which located where they should not 

![enter image description here][2]




  [1]: http://i.stack.imgur.com/GPhyQ.png
  [2]: http://i.stack.imgur.com/zuetp.png

Redefinition failed with error 62 while trying to profile an application

Can someone please explain me the difference between `Sleeping`, `Wait`, `Park`, and `Monitor` thread states in VisualVM.

![enter image description here][1]

This is what I have found:

`Running`: thread is still running. &lt;br /&gt;
`Sleeping`: thread is sleeping (method yield() was called on the thread object)&lt;br /&gt;
`Wait`: thread was blocked by a mutex or a barrier, and is waiting for another thread to release the lock&lt;br /&gt;
`Park`: parked threads are suspended until they are given a permit. Unparking a thread is usually done by calling method unpark() on the thread object&lt;br /&gt;
`Monitor`: threads are waiting on a condition to become true to resume execution

What I am unable to understand is the state Park, what actually suspends the thread? How do I detect in the code what has made the thread suspend its execution?

Can someone please guide me in this regard.

Thanks.


  [1]: http://i.stack.imgur.com/4WYvV.png

Content Type	Original Author	Original Content on Stackoverflow
Question	AndyF	View Question on Stackoverflow
Solution 1 - Java	Tomas Hurka	View Answer on Stackoverflow

VisualVM and Self Time

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