[Pkg-gridengine-devel] Bug#698286: incorrect value for "max vmem" is reported

[Alois Schloegl]

Package: gridengine*

Version: 6.2u5-1


When a job has finished, the "max vmem" value as it was actually used is
reported to the user.
Unfortunately, the reported value is never larger than 4G also the
application has clearly used more than 4G of Memory.
I've been testing this with Octave as well as mathematica.

Based on some preliminary tests, it seems that the reported value is the
(real value module 2^32). Thus, if more then 4G of vmem are used, the
reported maxvmem value is meaningless.

attached are:

- an Octave sample script, allocating 600M of random double precision
numbers resulting in 4.8GB memory need.
- the script for submission to the grid engine
    qsub memtest03.m

The e.mail report contains this:
Job 4709696 (MEMTEST02) Complete
 User             = schloegl
 Queue            = main.q at nick13.ista.local
 Host             = nick13.ista.local
 Start Time       = 01/16/2013 11:19:11
 End Time         = 01/16/2013 11:19:36
 User Time        = 00:00:23
 System Time      = 00:00:02
 Wallclock Time   = 00:00:25
 CPU              = 00:00:25
 Max vmem         = 710.246M
 Exit Status      = 0


The correct value of "Max vmem" should be 4.47GB or more. But its close
to mod(8*6e8,2^32)=505032704 (this is plausible when we assume 200MB
overhead by Octave).


maxvmem is an important variable of optimizing the use of a cluster.
Users can control how much memory is is required, which is then used by
the grid engine for scheduleing. For this reason, its important that a
meaningful value for maxvmem is reported. Therefore I suggest a severity
level "important".


Severity: important


Alois






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