memorygraph

MATLAB/octave unix tool to record true MATLAB/octave memory and CPU usage vs time

Alex Barnett 1/30/18

One point of this tool is to be able to extract reliable true peak RAM usage by a MATLAB/ocatve code, without the need to continuously human-read (h)top.

Installation

Place the code memorygraph.m somewhere in your MATLAB/octave path.

Usage

From MATLAB/octave, to start a graph (starts recording to a temp file in current directory):

memorygraph('start');

This samples every 1 sec. If you want more often use, eg

opts.dt = 0.1; memorygraph('start',opts);

This, or smaller dt, may cause top to slow down the CPU.

To read off graph recorded so far (this may be done multiple times):

[bytes est_times cpu_times cpu_usages] = memorygraph('get');

This gives outputs:

bytes : total RAM used by MATLAB/octave, in bytes
est_times : estimated clock time in secs since graph started
cpu_times : MATLAB/octave CPU time used (counting all threads) reported by top
cpu_usages : current percentage CPU usage by MATLAB/octave at each time

To clean up (sadly, this currently also kills all instances of top the user has!):

memorygraph('done');

Without args: does a self-test, produces the graph shown above.

Notes:

• Linux/unix only. Tested in MATLAB and octave.
• Very crude: assumes only one MATLAB instance per user, and no other instances of top running by user. Hard-coded temp-file. Etc.
• If only a few secs have elapsed, the memory graph can come back empty. This is because of caching of the pipe to the temp file.
• Max run time is baked in at 1e4 secs (about 3 hrs).
• The 'top' display config must be standard (no changes to /etc/toprc nor ~/.toprc).

Issues:

• How do we get actual time without estimating?
• How get PID of the spawned process to kill it and only it?

Please contribute fixes for the above issues.