Dr. Dobb's is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.


Channels ▼
RSS

Parallel

Performance Portable C++


STL versus Naked Pointers

I initially ran the benchmarks for this article using STL vectors to store data, but was curious how the STL performance compared to using naked pointers. Listing Five (available online) uses the restrict keyword with pointers in place of STL vectors.

In Figures 5, 6, and 7, I plot the ratio of the Pointer time to the STL time for the Triangle, Quadrilateral, and Brick benchmarks, respectively (a value less than 1 means the naked pointers are faster). The Quadrilateral benchmark results show that the pathscale 3.0 compiler on the Opteron ran 32 percent faster on average when using restricted pointers instead of the STL. On the other hand, the g++ compiler ran slightly faster on every benchmark configuration when using the STL. I had to omit the XlC compiler from this comparison because of overly aggressive optimizations that occurred when using pointers.

Figure 5: Point class/Triangle class.

Figure 6: Point class/Quadrilateral class.

Figure 7: Point class/Brick class.


Related Reading


More Insights






Currently we allow the following HTML tags in comments:

Single tags

These tags can be used alone and don't need an ending tag.

<br> Defines a single line break

<hr> Defines a horizontal line

Matching tags

These require an ending tag - e.g. <i>italic text</i>

<a> Defines an anchor

<b> Defines bold text

<big> Defines big text

<blockquote> Defines a long quotation

<caption> Defines a table caption

<cite> Defines a citation

<code> Defines computer code text

<em> Defines emphasized text

<fieldset> Defines a border around elements in a form

<h1> This is heading 1

<h2> This is heading 2

<h3> This is heading 3

<h4> This is heading 4

<h5> This is heading 5

<h6> This is heading 6

<i> Defines italic text

<p> Defines a paragraph

<pre> Defines preformatted text

<q> Defines a short quotation

<samp> Defines sample computer code text

<small> Defines small text

<span> Defines a section in a document

<s> Defines strikethrough text

<strike> Defines strikethrough text

<strong> Defines strong text

<sub> Defines subscripted text

<sup> Defines superscripted text

<u> Defines underlined text

Dr. Dobb's encourages readers to engage in spirited, healthy debate, including taking us to task. However, Dr. Dobb's moderates all comments posted to our site, and reserves the right to modify or remove any content that it determines to be derogatory, offensive, inflammatory, vulgar, irrelevant/off-topic, racist or obvious marketing or spam. Dr. Dobb's further reserves the right to disable the profile of any commenter participating in said activities.

 
Disqus Tips To upload an avatar photo, first complete your Disqus profile. | View the list of supported HTML tags you can use to style comments. | Please read our commenting policy.