Re: Re: Re: Re: Question for using ASM to log the method invocation trace.

Tomcat used to (might still) kill shutdown hooks if they took too long. Emma was 
one such user of shutdown hooks that suffered badly as it didn't get time to 
write out its coverage data before the thread was killed. I had to use Grobo 
with continuous writing instead to get complete coverage picture.

So you don't want to spend a long time in the shutdown hook, but a couple of 
seconds of work is not unreasonable. Any more than a few seconds and you might 
want another mechanism (continuous writing with a small buffer that is cleared 
by the shutdown hook).

PK



________________________________
From: Scott Vachalek <[email protected]>
To: Sai Zhang <[email protected]>
Cc: Paul Keeble <[email protected]>; Zhongxian Gu <[email protected]>; [email protected]
Sent: Thu, 22 July, 2010 23:09:11
Subject: [asm] Re: Re: Re: Question for using ASM to log the method invocation 
trace.

You can put anything into a shutdown hook but it's not really designed for doing 
much more than closing resources etc.  I imagine if you take too long, you risk 
having things like the garbage collector go away before you are done.  It's also 
not a very user-friendly model, to suddenly start doing a lot of work when the 
user is trying to quit the application.


On Thu, Jul 22, 2010 at 1:14 PM, Sai Zhang <[email protected]> wrote:

Hi all:
>
>Setting up a shutdown hook for "cleaning" the instrumentation tasks seems to be 
>a good practice. However, I am
>wondering could I insert "any" code to the code block of the shutdown hook ?
>
>that is:
>
>
>
>Runtime.getRuntime().addShutdownHook(new Thread() {
>  public  void run() {
>     
>       //Could i insert arbitrary code here as normal Java programs?    
>      //Could I do some sophisticated post-execution program analysis tasks here 
>without producing a trace file? 
>
>
>}});
>
>
>It seems that the shutdown hook may have some "side-effect". I have a fairly 
>complex procedure m() which
>throws no exception when calling directly from main. However, it behaves 
>strangely when putting into the hook code block.
>
>I am just guessing is there any special side-effects here?
>
>thanks. Any comments are highly appreciated.
>
>-
>Sai
>
>
>
>
>On Wed, Jun 30, 2010 at 3:13 AM, Paul Keeble <[email protected]> wrote:
>
>Say you have a class:
>>class Tracer {
>>public static void trace(String )
>>
>>
>>public static void close()
>>}
>>
>>
>>Then you can happily insert the calls to Tracer.trace for the instrumenting. You 
>>can also right at the beginning of the program (before you instrument anything 
>>and when you set-up the FileWriter to begin with) set-up a shutdown hook using 
>>something like:
>>
>>
>>Runtime.getRuntime().addShutdownHook(new Thread() {
>>  public void run() {
>>    Tracer.close();
>>}});
>>
>>
>>Its not a concern of the tracing to get the file stream closed, it is for the 
>>shutdown of the program.
>>
>>
>>PK
>>
>>
>>
________________________________
 From: Zhongxian Gu <[email protected]>
>>To: [email protected]
>>Sent: Wed, 30 June, 2010 5:10:33
>>Subject: [asm] Question for using ASM to log the method invocation trace.
>>
>>
>>Hi all,
>>
>>I wish to use ASM to instrument the code and during the run, record the method 
>>invocation trace. I use AdviceAdapter to do that. To enhance the performance,
>>I use BufferedWriter to print info to the log file. The problem is that I don't 
>>know how to instrument the code to close the BufferedWriter. I must call it 
>>until all the 
>>
>>methods called which is only known at run-time. Without calling close method 
>>will cause information missing in the buffer. 
>>
>>
>>I wonder if some of you have also experienced this condition and could you give 
>>me some hints. Thanks
>>
>>Best
>>
>>Zhongxian
>>
>>-- 
>>Zhongxian Gu
>>http://wwwcsif.cs.ucdavis.edu/~gu/
>>Ph.D. Student in Computer Science, UC Davis
>>2249 Kemper Hall 
>>
>>
>>
>>
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>
>
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