<div dir="ltr">Depends on what people want to use the reported speedup for, I suppose. The easy way is to simply report sum(obs_time) / max(correlate_time), like you suggest. That naturally takes into account inefficiencies in allocation across multiple jobs and gives a 'real world' speedup. So if someone splits their jobs in such a way that one job takes much longer, then the speedup reported is representative of the real-world time taken to finish everything. I think this is a good default.<div><br></div><div>That's one extreme. The other extreme is if you assume that as soon as one job finishes someone else takes those resources and starts using them for something else useful, and so you want to report the weighted average speedup of the individual jobs. Each individual job has a speedup of s_i = obs_time_i/correlate_time_i, and then you form the overall speedup by sum(s_i * obs_time_i) / sum(obs_time_i).</div><div><br></div><div>Those two measures are useful for different things, so probably it would be good to report both. But I think for most people the first is more useful.<br><div><br></div><div>Cheers,</div><div>Adam</div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 28 April 2017 at 08:37, Stuart Weston <span dir="ltr"><<a href="mailto:stuart.weston@aut.ac.nz" target="_blank">stuart.weston@aut.ac.nz</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal">The simple one head -> many workers we have speedup factor:<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Speedup = obs_time / corr_time<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">So say 4hrs observing is correlated in ~10.3 hrs, a speedup of 0.388.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Now in the scenario where we split the job between multiple heads, so head_1 does 0-2 hrs and head_2 does 2-4 hrs. How do we want to define the speedup here ?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Each will take slightly different times due to many external factors, but both are started at the same time (within fractions of a second)<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">So head_1 takes 5.1 hrs to correlate 2 hrs of observing, and head_2 takes 5.3 hrs for the other 2 hrs.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">We have correlated the same 4hrs of data but in approx half the elapsed time. So would you be happy for me to define speedup now as:<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Speedup = sum(obs_time_1, obs_time_2) / max(corr_time(head_1,head_2))<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">In this case it would be say 4/5.3 = 0.75. Now this doesn’t work if the split is un-even for the obs_time between the two heads.
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Just looking for a way to define my benchmarks (agreeable to the community) for cloud correlation and using multiple heads and breaking a job up between heads on different hypervisors.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Stuart Weston Bsc (Hons), MPhil (Hons), MInstP</span><span style="color:black"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Mobile: 021 713062</span><span style="color:black"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Skype: stuart.d.weston<br>
Email: <a href="mailto:stuart.weston@aut.ac.nz" target="_blank"><span style="color:blue">stuart.weston@aut.ac.nz</span></a></span><span style="color:black"><u></u><u></u></span></p>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr" style="font-size:12.8000001907349px"><div dir="ltr" style="font-size:12.8px"><div dir="ltr" style="font-size:12.8px"><div dir="ltr" style="font-size:12.8px"><div dir="ltr" style="font-size:12.8px">!=============================================================!<br>Dr. Adam Deller </div><div dir="ltr" style="font-size:12.8px">ARC Future Fellow, Senior Lecturer</div><div style="font-size:12.8px">Centre for Astrophysics & Supercomputing </div><div dir="ltr" style="font-size:12.8px">Swinburne University of Technology <br>John St, Hawthorn VIC 3122 Australia</div><div style="font-size:12.8px">phone: +61 3 9214 5307</div><div style="font-size:12.8px">fax: +61 3 9214 8797</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">office days (usually): Mon-Thu<br>!=============================================================!</div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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