mirror of
https://github.com/gperftools/gperftools
synced 2024-12-23 15:52:10 +00:00
265 lines
6.6 KiB
HTML
265 lines
6.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<HTML>
|
|
|
|
<HEAD>
|
|
<link rel="stylesheet" href="designstyle.css">
|
|
<title>Google CPU Profiler Binary Data File Format</title>
|
|
</HEAD>
|
|
|
|
<BODY>
|
|
|
|
<h1>Google CPU Profiler Binary Data File Format</h1>
|
|
|
|
<p align=right>
|
|
<i>Last modified
|
|
<script type=text/javascript>
|
|
var lm = new Date(document.lastModified);
|
|
document.write(lm.toDateString());
|
|
</script></i>
|
|
</p>
|
|
|
|
<p>This file documents the binary data file format produced by the
|
|
Google CPU Profiler. For information about using the CPU Profiler,
|
|
see <a href="cpuprofile.html">its user guide</a>.
|
|
|
|
<p>The profiler source code, which generates files using this format, is at
|
|
<code>src/profiler.cc</code></a>.
|
|
|
|
|
|
<h2>CPU Profile Data File Structure</h2>
|
|
|
|
<p>CPU profile data files each consist of four parts, in order:
|
|
|
|
<ul>
|
|
<li> Binary header
|
|
<li> Binary profile records
|
|
<li> Binary trailer
|
|
<li> Text list of mapped objects
|
|
</ul>
|
|
|
|
<p>The binary data is expressed in terms of "slots." These are words
|
|
large enough to hold the program's pointer type, i.e., for 32-bit
|
|
programs they are 4 bytes in size, and for 64-bit programs they are 8
|
|
bytes. They are stored in the profile data file in the native byte
|
|
order (i.e., little-endian for x86 and x86_64).
|
|
|
|
|
|
<h2>Binary Header</h2>
|
|
|
|
<p>The binary header format is show below. Values written by the
|
|
profiler, along with requirements currently enforced by the analysis
|
|
tools, are shown in parentheses.
|
|
|
|
<p>
|
|
<table summary="Header Format"
|
|
frame="box" rules="sides" cellpadding="5" width="50%">
|
|
<tr>
|
|
<th width="30%">slot</th>
|
|
<th width="70%">data</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>0</td>
|
|
<td>header count (0; must be 0)</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>1</td>
|
|
<td>header slots after this one (3; must be >= 3)</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>2</td>
|
|
<td>format version (0; must be 0)</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>3</td>
|
|
<td>sampling period, in microseconds</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>4</td>
|
|
<td>padding (0)</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>The headers currently generated for 32-bit and 64-bit little-endian
|
|
(x86 and x86_64) profiles are shown below, for comparison.
|
|
|
|
<p>
|
|
<table summary="Header Example" frame="box" rules="sides" cellpadding="5">
|
|
<tr>
|
|
<th></th>
|
|
<th>hdr count</th>
|
|
<th>hdr words</th>
|
|
<th>version</th>
|
|
<th>sampling period</th>
|
|
<th>pad</th>
|
|
</tr>
|
|
<tr>
|
|
<td>32-bit or 64-bit (slots)</td>
|
|
<td>0</td>
|
|
<td>3</td>
|
|
<td>0</td>
|
|
<td>10000</td>
|
|
<td>0</td>
|
|
</tr>
|
|
<tr>
|
|
<td>32-bit (4-byte words in file)</td>
|
|
<td><tt>0x00000</tt></td>
|
|
<td><tt>0x00003</tt></td>
|
|
<td><tt>0x00000</tt></td>
|
|
<td><tt>0x02710</tt></td>
|
|
<td><tt>0x00000</tt></td>
|
|
</tr>
|
|
<tr>
|
|
<td>64-bit LE (4-byte words in file)</td>
|
|
<td><tt>0x00000 0x00000</tt></td>
|
|
<td><tt>0x00003 0x00000</tt></td>
|
|
<td><tt>0x00000 0x00000</tt></td>
|
|
<td><tt>0x02710 0x00000</tt></td>
|
|
<td><tt>0x00000 0x00000</tt></td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>The contents are shown in terms of slots, and in terms of 4-byte
|
|
words in the profile data file. The slot contents for 32-bit and
|
|
64-bit headers are identical. For 32-bit profiles, the 4-byte word
|
|
view matches the slot view. For 64-bit profiles, each (8-byte) slot
|
|
is shown as two 4-byte words, ordered as they would appear in the
|
|
file.
|
|
|
|
<p>The profiling tools examine the contents of the file and use the
|
|
expected locations and values of the header words field to detect
|
|
whether the file is 32-bit or 64-bit.
|
|
|
|
|
|
<h2>Binary Profile Records</h2>
|
|
|
|
<p>The binary profile record format is shown below.
|
|
|
|
<p>
|
|
<table summary="Profile Record Format"
|
|
frame="box" rules="sides" cellpadding="5" width="50%">
|
|
<tr>
|
|
<th width="30%">slot</th>
|
|
<th width="70%">data</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>0</td>
|
|
<td>sample count, must be >= 1</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>1</td>
|
|
<td>number of call chain PCs (num_pcs), must be >= 1</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>2 .. (num_pcs + 1)</td>
|
|
<td>call chain PCs, most-recently-called function first.
|
|
</tr>
|
|
</table>
|
|
|
|
<p>The total length of a given record is 2 + num_pcs.
|
|
|
|
<p>Note that multiple profile records can be emitted by the profiler
|
|
having an identical call chain. In that case, analysis tools should
|
|
sum the counts of all records having identical call chains.
|
|
|
|
<p><b>Note:</b> Some profile analysis tools terminate if they see
|
|
<em>any</em> profile record with a call chain with its first entry
|
|
having the address 0. (This is similar to the binary trailer.)
|
|
|
|
<h3>Example</h3>
|
|
|
|
This example shows the slots contained in a sample profile record.
|
|
|
|
<p>
|
|
<table summary="Profile Record Example"
|
|
frame="box" rules="sides" cellpadding="5">
|
|
<tr>
|
|
<td>5</td>
|
|
<td>3</td>
|
|
<td>0xa0000</td>
|
|
<td>0xc0000</td>
|
|
<td>0xe0000</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>In this example, 5 ticks were received at PC 0xa0000, whose
|
|
function had been called by the function containing 0xc0000, which had
|
|
been called from the function containing 0xe0000.
|
|
|
|
|
|
<h2>Binary Trailer</h2>
|
|
|
|
<p>The binary trailer consists of three slots of data with fixed
|
|
values, shown below.
|
|
|
|
<p>
|
|
<table summary="Trailer Format"
|
|
frame="box" rules="sides" cellpadding="5" width="50%">
|
|
<tr>
|
|
<th width="30%">slot</th>
|
|
<th width="70%">value</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>0</td>
|
|
<td>0</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>1</td>
|
|
<td>1</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>2</td>
|
|
<td>0</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>Note that this is the same data that would contained in a profile
|
|
record with sample count = 0, num_pcs = 1, and a one-element call
|
|
chain containing the address 0.
|
|
|
|
|
|
<h2>Text List of Mapped Objects</h2>
|
|
|
|
<p>The binary data in the file is followed immediately by a list of
|
|
mapped objects. This list consists of lines of text separated by
|
|
newline characters.
|
|
|
|
<p>Each line is one of the following types:
|
|
|
|
<ul>
|
|
<li>Build specifier, starting with "<tt>build=</tt>". For example:
|
|
<pre> build=/path/to/binary</pre>
|
|
Leading spaces on the line are ignored.
|
|
|
|
<li>Mapping line from ProcMapsIterator::FormatLine. For example:
|
|
<pre> 40000000-40015000 r-xp 00000000 03:01 12845071 /lib/ld-2.3.2.so</pre>
|
|
The first address must start at the beginning of the line.
|
|
</ul>
|
|
|
|
<p>Unrecognized lines should be ignored by analysis tools.
|
|
|
|
<p>When processing the paths see in mapping lines, occurrences of
|
|
<tt>$build</tt> followed by a non-word character (i.e., characters
|
|
other than underscore or alphanumeric characters), should be replaced
|
|
by the path given on the last build specifier line.
|
|
|
|
<hr>
|
|
<address>Chris Demetriou<br>
|
|
<!-- Created: Mon Aug 27 12:18:26 PDT 2007 -->
|
|
<!-- hhmts start -->
|
|
Last modified: Mon Aug 27 12:18:26 PDT 2007 (cgd)
|
|
<!-- hhmts end -->
|
|
</address>
|
|
</BODY>
|
|
</HTML>
|