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| <h1 class="settitle">Stress 1.0.4</h1> |
| <div class="contents"> |
| <h2>Table of Contents</h2> |
| <ul> |
| <li><a name="toc_Top" href="#Top">Stress</a> |
| <li><a name="toc_Overview" href="#Overview">1 Overview of <samp><span class="command">stress</span></samp></a> |
| <li><a name="toc_Invoking-stress" href="#Invoking-stress">2 Invoking stress</a> |
| <li><a name="toc_Examples" href="#Examples">3 Example invocations</a> |
| <li><a name="toc_Copying-This-Manual" href="#Copying-This-Manual">Appendix A Copying This Manual</a> |
| <li><a name="toc_Index" href="#Index">Index</a> |
| </li></ul> |
| </div> |
| |
| |
| |
| <div class="node"> |
| <p><hr> |
| <a name="Top"></a> |
| Next: <a rel="next" accesskey="n" href="#Overview">Overview</a>, |
| Up: <a rel="up" accesskey="u" href="#dir">(dir)</a> |
| |
| </div> |
| |
| <h2 class="unnumbered">Stress</h2> |
| |
| <ul class="menu"> |
| <li><a accesskey="1" href="#Overview">Overview</a>: Overview of <samp><span class="command">stress</span></samp>. |
| <li><a accesskey="2" href="#Invoking-stress">Invoking stress</a>: How to run <samp><span class="command">stress</span></samp>. |
| <li><a accesskey="3" href="#Examples">Examples</a>: Some example invocations. |
| <li><a accesskey="4" href="#Copying-This-Manual">Copying This Manual</a> |
| <li><a accesskey="5" href="#Index">Index</a> |
| </ul> |
| |
| <div class="node"> |
| <p><hr> |
| <a name="Overview"></a> |
| Next: <a rel="next" accesskey="n" href="#Invoking-stress">Invoking stress</a>, |
| Previous: <a rel="previous" accesskey="p" href="#Top">Top</a>, |
| Up: <a rel="up" accesskey="u" href="#Top">Top</a> |
| |
| </div> |
| |
| <h2 class="chapter">1 Overview of <samp><span class="command">stress</span></samp></h2> |
| |
| <p><samp><span class="command">stress</span></samp> is not a benchmark, but is rather a tool designed to put |
| given subsytems under a specified load. Instances in which this is useful |
| include those in which a system administrator wishes to perform tuning |
| activities, a kernel or libc programmer wishes to evaluate denial of service |
| possibilities, etc. |
| |
| <div class="node"> |
| <p><hr> |
| <a name="Invoking-stress"></a> |
| Next: <a rel="next" accesskey="n" href="#Examples">Examples</a>, |
| Previous: <a rel="previous" accesskey="p" href="#Overview">Overview</a>, |
| Up: <a rel="up" accesskey="u" href="#Top">Top</a> |
| |
| </div> |
| |
| <h2 class="chapter">2 Invoking stress</h2> |
| |
| <p><a name="index-stress-1"></a><a name="index-invoking-_0040command_007bstress_007d-2"></a> |
| The format for running the <samp><span class="command">stress</span></samp> program is: |
| |
| <pre class="example"> <samp><span class="command">stress</span></samp> [<var>option</var> [<var>args</var>]] ... |
| </pre> |
| <p><samp><span class="command">stress</span></samp> supports the following options: |
| |
| <dl> |
| <dt>‘<samp><span class="samp">-?</span></samp>’<dt>‘<samp><span class="samp">--help</span></samp>’<dd>Show help information. |
| |
| <dt>‘<samp><span class="samp">--version</span></samp>’<dd>Show version information. |
| |
| <br><dt>‘<samp><span class="samp">-v</span></samp>’<dt>‘<samp><span class="samp">--verbose</span></samp>’<dd>Turn up verbosity. |
| |
| <br><dt>‘<samp><span class="samp">-q</span></samp>’<dt>‘<samp><span class="samp">--quiet</span></samp>’<dd>Turn down verbosity. |
| |
| <br><dt>‘<samp><span class="samp">-n</span></samp>’<dt>‘<samp><span class="samp">--dry-run</span></samp>’<dd>Show what would have been done. |
| |
| <br><dt>‘<samp><span class="samp">-t </span><var>secs</var></samp>’<dt>‘<samp><span class="samp">--timeout </span><var>secs</var></samp>’<dd>Time out after <var>secs</var> seconds. |
| |
| <dt>‘<samp><span class="samp">--backoff </span><var>usecs</var></samp>’<dd>Wait for factor of <var>usecs</var> microseconds before starting work. |
| |
| <br><dt>‘<samp><span class="samp">-c </span><var>forks</var></samp>’<dt>‘<samp><span class="samp">--cpu </span><var>forks</var></samp>’<dd>Spawn <var>forks</var> processes each spinning on ‘<samp><span class="samp">sqrt()</span></samp>’. |
| |
| <br><dt>‘<samp><span class="samp">-i </span><var>forks</var></samp>’<dt>‘<samp><span class="samp">--io </span><var>forks</var></samp>’<dd>Spawn <var>forks</var> processes each spinning on ‘<samp><span class="samp">sync()</span></samp>’. |
| |
| <br><dt>‘<samp><span class="samp">-m </span><var>forks</var></samp>’<dt>‘<samp><span class="samp">--vm </span><var>forks</var></samp>’<dd>Spawn <var>forks</var> processes each spinning on ‘<samp><span class="samp">malloc()</span></samp>’. |
| |
| <dt>‘<samp><span class="samp">--vm-bytes </span><var>bytes</var></samp>’<dd>Allocate <var>bytes</var> number of bytes. The default is 1. |
| |
| <dt>‘<samp><span class="samp">--vm-hang</span></samp>’<dd>Instruct each vm hog process to go to sleep after allocating memory. This |
| contrasts with their normal behavior, which is to free the memory and |
| reallocate <em>ad infinitum</em>. This is useful for simulating low memory |
| conditions on a machine. For example, the following command allocates 256M of |
| RAM and holds it until killed. |
| |
| <pre class="example"> % stress --vm 2 --vm-bytes 128M --vm-hang |
| </pre> |
| <br><dt>‘<samp><span class="samp">-d </span><var>forks</var></samp>’<dt>‘<samp><span class="samp">--hdd </span><var>forks</var></samp>’<dd>Spawn <var>forks</var> processes each spinning on ‘<samp><span class="samp">write()</span></samp>’. |
| |
| <dt>‘<samp><span class="samp">--hdd-bytes </span><var>bytes</var></samp>’<dd>Write <var>bytes</var> number of bytes. The default is 1GB. |
| |
| <dt>‘<samp><span class="samp">--hdd-noclean</span></samp>’<dd>Do not unlink file(s) to which random ASCII data is written. |
| |
| </dl> |
| |
| <p>Note: Suffixes may be s,m,h,d,y (time) or k,m,g (size). |
| |
| <div class="node"> |
| <p><hr> |
| <a name="Examples"></a> |
| Next: <a rel="next" accesskey="n" href="#Copying-This-Manual">Copying This Manual</a>, |
| Previous: <a rel="previous" accesskey="p" href="#Invoking-stress">Invoking stress</a>, |
| Up: <a rel="up" accesskey="u" href="#Top">Top</a> |
| |
| </div> |
| |
| <h2 class="chapter">3 Example invocations</h2> |
| |
| <p>The simple case is that you just want to bring the system load average up to |
| an arbitrary value. The following forks 13 processes, each of which spins |
| in a tight loop calculating the sqrt() of a random number acquired with |
| rand(). |
| |
| <p>% ‘<samp><span class="samp">stress -c 13</span></samp>’ |
| |
| <p>Long options are supported, as well as is making the output less verbose. |
| The following forks 1024 processes, and only reports error messages if any. |
| |
| <p>% ‘<samp><span class="samp">stress --quiet --cpu 1k</span></samp>’ |
| |
| <p>To see how your system performs when it is I/O bound, use the -i switch. |
| The following forks 4 processes, each of which spins in a tight loop calling |
| sync(), which is a system call that flushes memory buffers to disk. |
| |
| <p>% ‘<samp><span class="samp">stress -i 4</span></samp>’ |
| |
| <p>Multiple hogs may be combined on the same command line. The following does |
| everything the preceding examples did in one command, but also turns up the |
| verbosity level as well as showing how to cause the command to |
| self-terminate after 1 minute. |
| |
| <p>% ‘<samp><span class="samp">stress -c 13 -i 4 --verbose --timeout 1m</span></samp>’ |
| |
| <p>You can write a file of arbitrary length to disk. The file is created with |
| mkstemp() in the current directory, the default is to unlink it, but |
| unlinking can be overridden with the –hdd-noclean flag. |
| |
| <p>% ‘<samp><span class="samp">stress -d 1 --hdd-noclean --hdd-bytes 13</span></samp>’ |
| |
| <p>Large file support is enabled. |
| |
| <p>% ‘<samp><span class="samp">stress -d 1 --hdd-noclean --hdd-bytes 3G</span></samp>’ |
| |
| <div class="node"> |
| <p><hr> |
| <a name="Copying-This-Manual"></a> |
| Next: <a rel="next" accesskey="n" href="#Index">Index</a>, |
| Previous: <a rel="previous" accesskey="p" href="#Examples">Examples</a>, |
| Up: <a rel="up" accesskey="u" href="#Top">Top</a> |
| |
| </div> |
| |
| <h2 class="appendix">Appendix A Copying This Manual</h2> |
| |
| <p>You may copy this manual under the terms of the GNU General Public License. |
| |
| <div class="node"> |
| <p><hr> |
| <a name="Index"></a> |
| Previous: <a rel="previous" accesskey="p" href="#Copying-This-Manual">Copying This Manual</a>, |
| Up: <a rel="up" accesskey="u" href="#Top">Top</a> |
| |
| </div> |
| |
| <h2 class="unnumbered">Index</h2> |
| |
| <ul class="index-cp" compact> |
| <li><a href="#index-invoking-_0040command_007bstress_007d-2">invoking <samp><span class="command">stress</span></samp></a>: <a href="#Invoking-stress">Invoking stress</a></li> |
| <li><a href="#index-stress-1"><code>stress</code></a>: <a href="#Invoking-stress">Invoking stress</a></li> |
| </ul></body></html> |
| |
