valgrind-cputil

cputil - a valgrind tool for estimating CPU utilization

Copyright (C) 2016-2017 -- Matthew R. Wette.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included with the distribution as COPYING.DOC.

The cputil program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

Introduction

This valgrind tool provides approximate cycle counts for user-defined regions of code. It works on a per-thread basis. The following program, when executed under cputil/valgrind will report the estimated number of clock cycles required to execute foo(). The default processor model is a PowerPC750, but can be changed with a user-loadable table.

#include <stdio.h>
#include "cputil.h"
int main() {
  long cycles;
  CU_REGTHR();                /* register the current thread */
  for (i = 0; i < 5; i++) {
    CU_CLRCTR();              /* clear the cycle counter */
    foo(i);
    cycles += CU_GETCTR();    /* read the cycle counter */
    bar(i);
  }
  printf("clk-cycles=%d\n", cycles)
}

Installation

This works with valgrind-3.11.0. Goal will be to work w/ >3.0.

To install:

1. Download and unpack valgring-3.11.0

2. Clone or otherwise install this cputil distribution in a directory called cputil under valgrind-3.11.0

3. in the subdirectory cputil, execute patch1:

   $ pwd
   .../valgring-3.11.0/cputil
   $ ./patch1
   

4a. In the valgrind top directory run configure, make and install:

   $ ./configure --prefix=/usr/local
   $ make 
   $ make install

4b. Optionally, if you want a minimal distribution, do this:

   $ ./configure --prefix=/usr/local
   $ mkdir -p /var/tmp/bindist
   $ make DESTDIR=/var/tmp/bindist pkglibdir=/usr/local/lib/cputil
   $ make DESTDIR=/var/tmp/bindist pkglibdir=/usr/local/lib/cputil install
   $ sh cputil/mindist /var/tmp/bindist /usr/local/lib/cputil

dumping the op-count tables

To dump the internal tables execute

   $ valgrind --tool=cputil --dump-op-tables=dump.cut true

There is no way to dump the op-tables w/o specifing a program to so we use use /bin/true.

loading user-defined op-count tables

A dumped op table can be edited for clock counts and used for another run:

   $ valgrind --tool=cputil --load-op-tables=dump.cut my_program

Threads

Support for multi-threaded code has been added.

Demo

Look in cputil/tests/demo1.c