| author | Matti Laitinen <matti.t.laitinen@nokia.com> |
| Thu, 11 Feb 2010 15:32:31 +0200 | |
| changeset 2 | b9ab3b238396 |
| child 5 | 844b047e260d |
| permissions | -rw-r--r-- |
|
2
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
1 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
2 |
|
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
3 |
<html> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
4 |
<head> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
5 |
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
6 |
<title>Dynamic Memory Characteristics</title> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
7 |
<link href="../../../book.css" rel="stylesheet" type="text/css"> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
8 |
</head> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
9 |
|
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
10 |
<body> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
11 |
<h3>Dynamic Memory Characteristics</h3> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
12 |
<p> Symbian programming guidelines instruct that memory should be handled as a scarce resource. Basically, memory should be allocated on demand and freed as soon as possible. Based on gathered empirical data, a typical characteristic of a dynamic memory implementation pattern in an Symbian application is the following:</p> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
13 |
<ol> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
14 |
<li>Allocate memory</li> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
15 |
<li>Reset contents of memory</li> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
16 |
<li>Do something</li> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
17 |
<li>Free the allocated memory</li> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
18 |
</ol> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
19 |
<p>If the sequential functional trace shows the above pattern and it occurs frequently in the application, try to determine why it happens. Determine whether allocation and free operations for objects of the same type and size could be replaced with a simple cache.</p> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
20 |
<p>If an application uses dynamic memory extensively, it is beneficial to know statistics of utilized block sizes. Very small block sizes used frequently are potential performance bottlenecks.</p> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
21 |
<div id="footer">Copyright © 2009 Nokia Corporation and/or its subsidiary(-ies). All rights reserved. <br>License: <a href="http://www.eclipse.org/legal/epl-v10.html">http://www.eclipse.org/legal/epl-v10.html</a></div> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
22 |
</body> |
|
b9ab3b238396
Initial version of Performance Investigator under EPL
Matti Laitinen <matti.t.laitinen@nokia.com>
parents:
diff
changeset
|
23 |
</html> |