New Statistical Algorithms for the Analysis of Mass - FU Berlin, FB MI ...
New Statistical Algorithms for the Analysis of Mass - FU Berlin, FB MI ...
New Statistical Algorithms for the Analysis of Mass - FU Berlin, FB MI ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
6.2. CASE STUDIES 159<br />
The peak picking algorithm changed slightly opposed to <strong>the</strong> original version<br />
on a single core CPU and is now as follows:<br />
1. Load a 1D spectrum into main memory (about 670KB in 54.000 x/y<br />
data points)<br />
2. Split spectrum into pieces <strong>of</strong> size min(256KB,<br />
spectrum size[KB]<br />
#SP Us )<br />
3. Until pieces are available: Send pieces to SPEs to find peaks<br />
4. Wait <strong>for</strong> all SPEs to finish<br />
5. Merge results<br />
Results<br />
The results are shown in Table 6.2.4.<br />
Machine Test # SPEs Time [ms] per spectrum<br />
Intel # w/o fitting 1 8200<br />
Intel # w/ fitting 1 13300<br />
PS3 w/o fitting 6 115<br />
PS3 w/ fitting 1 2250<br />
PS3 w/ fitting 6 750<br />
QS20 w/ fitting 1 2100<br />
QS20 w/ fitting 6 730<br />
QS20 w/ fitting 12 410<br />
QS20 w/ fitting 16 350<br />
Table 6.2.1: This shows <strong>the</strong> PS3 per<strong>for</strong>mance tests. # : Standard desktop single-core<br />
PC at 3.2GHz<br />
6.2.5 Integrating <strong>of</strong> Non-Grid Applications on <strong>the</strong> Example <strong>of</strong><br />
Matlab Scripts and Linux Binaries<br />
Background<br />
As explained in <strong>the</strong> previous chapter, writing QAD Grid applications is not<br />
a very complex task but still, some modifications must be made to standard<br />
code. Thanks to <strong>the</strong> QAD Grid worker concept, <strong>the</strong>re are ways to circumvent<br />
even this requirement as we will show below <strong>for</strong> algorithms existing as Matlab<br />
script and <strong>for</strong> binaries where <strong>the</strong> source code obviously cannot be modified.<br />
Besides <strong>the</strong> obvious advantages distributed computation <strong>of</strong>fers, e.g. Load balancing,<br />
ano<strong>the</strong>r very interesting point is service availability. That means, if we<br />
have many Matlab scripts providing <strong>the</strong> same service running on n different<br />
nodes in <strong>the</strong> network (and assume a stable QAD Grid server) <strong>the</strong>n failure <strong>of</strong><br />
up to n − 1 nodes still does not harm <strong>the</strong> availability <strong>of</strong> this service, since<br />
<strong>the</strong> QAD Grid server will distribute incoming jobs to <strong>the</strong> remaining running<br />
nodes.