Charm++ parallel programming system

[Eric Bohm <ebohm AT illinois.edu>]

Hello Roberto,

The former problem can usually be redressed by increasing the amount of log data which is held in memory before writing to disk.

Add +logsize 2000000
to the command line for your program execution, or a larger number if that is insufficient.  If that is not sufficient there are several slightly more intrusive schemes for collecting less data described in the manual, which we can discuss as necessary.

The second problem is similar in that you are trying to load more than the Java VM will handle in at least one of the threads.   You can address this by loading less data (fewer timelines, or a shorter time span).  If your machine has an unusually large amount of memory, it is possible to access it by passing very large values to  the -Xmx and -Xss command line flag which controls maximum VM memory and maximum thread stack size respectively.  The large gaps were probably due to the flush to disk events that you were warned about when the traces were made.

On 10/03/2013 07:24 PM, Roberto de Quadros Gomes wrote:

Hi people,

I am using Projections to analyse the ampi programs. However, sometimes when i use a large number of data, I received the messages like that:
*************************************************************
Warning: Projections log flushed to disk 24 times on 4 cores: 0 1 2 3 .
Warning: The performance data is likely invalid, unless the flushes have been explicitly synchronized by your program.
*************************************************************

First question...How can i avoid this warning?

Then, when I try open the timeline with Projections, it spend a long time and the terminal pops up a message as follow:
--------------------------------------------------
Exception in thread "Thread-1" java.lang.OutOfMemoryError: GC overhead limit exceeded
        at projections.analysis.LogEntry.<init>(LogEntry.java:49)
        at projections.analysis.LogLoader.createtimeline(LogLoader.java:1197)
        at projections.Tools.Timeline.Data.getData(Data.java:867)
        at projections.Tools.Timeline.TimelineRunnableFileReader.run(TimelineRunnableFileReader.java:15)
        at java.lang.Thread.run(Thread.java:724)
 -----------------------------------------------------

I don't have sure if there are correlation between the symptoms, but after it completes the reading,  the timeline is shown and many gaps are present. 

I am using
Projections version: 7.0

Thanks

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