[Beowulf] stace_analyzer.pl can't work.

Joe Landman landman at scalableinformatics.com
Tue Sep 16 08:13:10 EDT 2008


A quick patchy-patchy for 310



--- strace_analyzer.pl	2008-09-16 07:57:34.000000000 -0400
+++ strace_analyzer_new.pl	2008-09-16 08:01:45.000000000 -0400
@@ -307,7 +307,7 @@
            $junk =~ s/[^0-9]//g;

            # Keep track of total number bytes read
-          $ReadBytesTotal += $junk;
+          $ReadBytesTotal += $junk if ($junk != -1);

            # Clean up write unit
            ($junk1, $junk2)=split(/\,/,$cmd_unit);


There may be other error return codes which are negative, so if you want 
to filter those as well, use "(if $junk < 0)" rather than the above.

As for the rest of the code structure, writing this parser isn't all 
that hard, and for those with smaller memories but bigger disks (and a 
desired to analyze large straces), we could use the DBIx::SimplePerl 
module.  Jeff is already putting his arrays together as hashes, and that 
module makes it real easy to dump a hash data structure directly into a 
database, say a SQLite3 database.  Which, curiously, could make a bit of 
the code easier to deal with/write/debug.

The issue you have to worry about in dealing with huge streams of data, 
is running out of ram.  This happens.  Many "common" techniques fail 
when data gets very large (compared to something like ram).  We had to 
solve a large upload/download problem for a customer who decided to use 
a web server for multi gigabyte file upload/download form in an 
application.  The common solution was to pull everything in to ram and 
massage it from there.  This failed rather quickly.

I don't personally have large amounts of "free" time, but I could likely 
help out a bit with this.  Jeff, do you want me to create something on 
our mercurial server for this?  Or do you have it in SVN/CVS somewhere?

Joe


-- 
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
web  : http://www.scalableinformatics.com
        http://jackrabbit.scalableinformatics.com
phone: +1 734 786 8423 x121
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cell : +1 734 612 4615
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