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<?php require('start_page.php3'); start_page("about.php3","About OProfile") ?>
<h2>Overview</h2>
<p>
OProfile is a system-wide profiler for Linux x86 systems, capable of profiling
all running code at low overhead. OProfile is released under the GNU GPL.
</p>
<p>
It consists of a kernel module and a daemon for collecting sample data, and several
post-profiling tools for turning data into information.
</p>
<p>
OProfile leverages the hardware performance counters of the CPU to enable profiling
of a wide variety of interesting statistics, which can also be used for basic
time-spent profiling. All code is profiled: interrupt handlers, kernel modules, the kernel,
shared libraries, and applications (the only exception being the oprofile interrupt
handler itself).
</p>
<p>
OProfile is currently in alpha status; however it has proven stable over a large number
of differing configurations. As always, there is no warranty: OProfile may cause data
loss.
</p>
<h2>Features</h2>
<dl>
<dt>Unobtrusive</dt>
<dd>
No special recompilations, wrapper libraries or the like are necessary. Even debug symbols
(<tt>-g</tt> option to <tt>gcc</tt>) are not necessary unless you want to produce annotated source.
<br />
No kernel patch is needed - just insert the module.
</dd>
<dt>System-wide profiling</dt>
<dd>
All code running on the system is profiled, enabling analysis of system performance.
</dd>
<dt>Performance counter support</dt>
<dd>
Enables collection of various low-level data, and assocation with particular sections
of code.
</dd>
<dt>Low overhead</dt>
<dd>
OProfile has a typical overhead of 3-8%, dependent on sampling frequency and workload.
</dd>
<dt>Post-profile analysis</dt>
<dd>
Profile data can be produced on the function-level or instruction-level detail. Source trees
annotated with profile information can be created. A hit list of applications and functions
that take the most time across the whole system can be produced.
</dd>
<dt>System support</dt>
<dd>
OProfile works across a range of x86 CPUs, including the Athlon/Duron range. Full support for
Pentium IV is not yet present. OProfile will work against almost any 2.2 and 2.4 kernel, and
works on both UP and SMP systems.
</dd>
</dl>
<h2>History</h2>
<p>
The early versions of OProfile were developed as part credit for an M.Sc. in Computer Science. The
basic principles of the design were inspired by Compaq's <a href="links.php3">DCPI</a> profiler.
</p>
<?php require('end_page.php3'); end_page("about.php3"); ?>