Mercurial > hg > batch-feature-extraction-tool
diff Lib/fftw-3.2.1/doc/html/.svn/text-base/Cell-Caveats.html.svn-base @ 15:585caf503ef5 tip
Tidy up for ROLI
| author | Geogaddi\David <d.m.ronan@qmul.ac.uk> |
|---|---|
| date | Tue, 17 May 2016 18:50:19 +0100 |
| parents | 636c989477e7 |
| children |
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--- a/Lib/fftw-3.2.1/doc/html/.svn/text-base/Cell-Caveats.html.svn-base Wed May 04 11:02:59 2016 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,92 +0,0 @@ -<html lang="en"> -<head> -<title>Cell Caveats - FFTW 3.2.1</title> -<meta http-equiv="Content-Type" content="text/html"> -<meta name="description" content="FFTW 3.2.1"> -<meta name="generator" content="makeinfo 4.8"> -<link title="Top" rel="start" href="index.html#Top"> -<link rel="up" href="FFTW-on-the-Cell-Processor.html#FFTW-on-the-Cell-Processor" title="FFTW on the Cell Processor"> -<link rel="prev" href="Cell-Installation.html#Cell-Installation" title="Cell Installation"> -<link rel="next" href="FFTW-Accuracy-on-Cell.html#FFTW-Accuracy-on-Cell" title="FFTW Accuracy on Cell"> -<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> -<!-- -This manual is for FFTW -(version 3.2.1, 5 February 2009). - -Copyright (C) 2003 Matteo Frigo. - -Copyright (C) 2003 Massachusetts Institute of Technology. - - Permission is granted to make and distribute verbatim copies of - this manual provided the copyright notice and this permission - notice are preserved on all copies. - - Permission is granted to copy and distribute modified versions of - this manual under the conditions for verbatim copying, provided - that the entire resulting derived work is distributed under the - terms of a permission notice identical to this one. - - Permission is granted to copy and distribute translations of this - manual into another language, under the above conditions for - modified versions, except that this permission notice may be - stated in a translation approved by the Free Software Foundation. - --> -<meta http-equiv="Content-Style-Type" content="text/css"> -<style type="text/css"><!-- - pre.display { font-family:inherit } - pre.format { font-family:inherit } - pre.smalldisplay { font-family:inherit; font-size:smaller } - pre.smallformat { font-family:inherit; font-size:smaller } - pre.smallexample { font-size:smaller } - pre.smalllisp { font-size:smaller } - span.sc { font-variant:small-caps } - span.roman { font-family:serif; font-weight:normal; } - span.sansserif { font-family:sans-serif; font-weight:normal; } ---></style> -</head> -<body> -<div class="node"> -<p> -<a name="Cell-Caveats"></a> -Next: <a rel="next" accesskey="n" href="FFTW-Accuracy-on-Cell.html#FFTW-Accuracy-on-Cell">FFTW Accuracy on Cell</a>, -Previous: <a rel="previous" accesskey="p" href="Cell-Installation.html#Cell-Installation">Cell Installation</a>, -Up: <a rel="up" accesskey="u" href="FFTW-on-the-Cell-Processor.html#FFTW-on-the-Cell-Processor">FFTW on the Cell Processor</a> -<hr> -</div> - -<h3 class="section">6.2 Cell Caveats</h3> - - <ul> -<li>The FFTW benchmark program allocates memory using malloc() or -equivalent library calls, reflecting the common usage of the FFTW -library. However, you can sometimes improve performance significantly -by allocating memory in system-specific large TLB pages. E.g., we -have seen 39 GFLOPS/s for a 256 × 256 × 256 problem using -large pages, whereas the speed is about 25 GFLOPS/s with normal pages. -YMMV. - - <li>FFTW hoards all available SPEs for itself. You can optionally -choose a different number of SPEs by calling the undocumented -function <code>fftw_cell_set_nspe(n)</code>, where <code>n</code> is the number of desired -SPEs. Expect this interface to go away once we figure out how to -make FFTW play nicely with other Cell software. - - <p>In particular, if you try to link both the single and double precision -of FFTW in the same program (which you can do), they will both try -to grab all SPEs and the second one will hang. - - <li>The SPEs demand that data be stored in contiguous arrays aligned at -16-byte boundaries. If you instruct FFTW to operate on -noncontiguous or nonaligned data, the SPEs will not be used, -resulting in slow execution. See <a href="Data-Alignment.html#Data-Alignment">Data Alignment</a>. - - <li>The <code>FFTW_ESTIMATE</code> mode may produce seriously suboptimal plans, and -it becomes particularly confused if you enable both the SPEs and -Altivec. If you care about performance, please use <code>FFTW_MEASURE</code> -or <code>FFTW_PATIENT</code> until we figure out a more reliable performance model. - -</ul> - -<!-- --> -</body></html> -