[concurrency-interest] tools for parallel performance debugging

Danny Dig dig at illinois.edu
Mon Aug 29 14:57:43 EDT 2011


Thanks Nathan. These tools are all good suggestions. I am curious what
other tools do people on this mailing list use for parallel
programming in Java.

best,
Danny


On Thu, Aug 25, 2011 at 11:01 AM, Nathan Reynolds
<nathan.reynolds at oracle.com> wrote:
> For identifying threading correctness issues, I recommend using Java Path
> Finder (http://babelfish.arc.nasa.gov/trac/jpf).  It executes every possible
> thread scheduling combination.  It does so by trying one thread scheduling
> combination and then back tracking (i.e. revert the state of the program) to
> simulate other combinations.  If there is a data race or deadlock, it will
> find it and report it.  It doesn't just tell you that a data race or
> deadlock exists but the steps that got to that state.  Because of the number
> of combinations, it is best to run it on a small piece of the overall
> program.
>
> As for synchronization contention, there are several tools available.
> Looking through a dump of call stacks and seeing where the most threads are
> blocked works for cases where the lock is dropping the throughput by 10% or
> more.  The call stacks are easy to obtain but can be time consuming to sift
> through.  JRockit's Mission Control can tell you exactly which locks are
> most contended and give you the call stacks of where that lock is used.  I
> am pretty sure most of the profilers can tell you which locks are most
> contended, but since JRockit's Mission Control is free for me I haven't
> looked at the profilers for a while.  I thought that JConsole or some tool
> in the JDK could tell you the most contended lock... but I am really not
> sure of that.
>
> As for false sharing, this is something that only the processor can tell
> you.  For Intel, I *think* VTune can tell you about false sharing.  I know
> that VTune can deal with Java optimized code.
>
> Nathan Reynolds | Consulting Member of Technical Staff | 602.333.9091
> Oracle PSR Engineering | Server Technology
> On 8/24/2011 8:07 PM, Danny Dig wrote:
>
> This community has been providing some great library features for
> taming parallelism in Java.
>
> When it comes to tools for parallel performance debugging, it looks to
> me that Java is trailing behind C++/Intel's ParallelStudio, or
> C#/Microsoft's Visual Studio. When working with Java programs, what
> are the tools that you recommend for:
> - identifying threading correctness issues (e.g., data-races, deadlocks),
> - identifying performance issues (load imbalance, synchronization
> contention, false sharing)
>
> best,
> Danny
>
>



-- 
Danny Dig
Visiting Research Assistant Professor at UIUC

http://netfiles.uiuc.edu/dig/www

Motto: "Success is not for the chosen few but for the few who choose"



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