Dear Marcin, as for the error bars in the speed-up plot: speedup is a composite measure, i. e. it is computed by division of 2 measured values with uncertainty (sequential and parallel execution times), therefore I compute the relative uncertainty of the speedup as the sum of relative standard deviations for each of the measured values. Finally, absolute uncertainty of the speedup is computed as follows in python code:
std_speedup = ((std_seq/t_seq) + (std_par/t_par)) * speedup Thank you very much for asking about it because this is the part I am not 100% sure about. The above formula is correct when computing an error (uncertainty) of composite value created from combining measurements with measurement errors. So my understanding is that if we accept the standard deviation as a measure of measurement error then the above formula is correct. For the full picture here is the link to function responsible for speedup computation: link <https://github.com/Jakub-Golinowski/opencv_hpx_backend/blob/5a0f6459b48bce63d931ae0089c1695059ac9a1b/python/mandelbrot_benchmark/mandelbrot_benchmark.py#L140> However, now I think that other approach might be to simply compute 3 speedups for 3 experiments separately and then use the standard deviation of these speedups as the value for error bars, what do you think? If there is other convention for capturing uncertainty in the performance benchmark plots, please let me know. Best regards, Jakub Golinowski 2018-07-07 17:12 GMT+01:00 Jakub Golinowski <[email protected]>: > Dear Hartmut, > > I did not look thoroughly into the tbb and openmp implementations and > therefore do not have a satisfying understanding why HPX is slower than tbb > and openmp in my benchmark. > I can look into that and get back to you. > > Also, if you recall any materials or existing benchmarks that may be > useful for me in this matter please let me know. > > Best regards, > > Jakub Golinowski > > 2018-07-07 16:41 GMT+01:00 Hartmut Kaiser <[email protected]>: > >> Jakub, >> >> Thanks for your work on this! >> Do you have an understanding why HPX is slower than tbb and/or openmp yet? >> >> Regards Hartmut >> --------------- >> http://stellar.cct.lsu.edu >> https://github.com/STEllAR-GROUP/hpx >> >> >> > -----Original Message----- >> > From: [email protected] <[email protected]> >> On >> > Behalf Of Jakub Golinowski >> > Sent: Saturday, July 7, 2018 9:57 AM >> > To: [email protected]; [email protected] >> > Subject: [STE||AR Gsoc] GSoC 2nd evaluation summary >> > >> > Hello, >> > >> > in this e-mail I am enclosing the link to the google docs with the short >> > summary of the progress I have made over the period of 2 moths of Google >> > Summer of Code. >> > >> > https://docs.google.com/document/d/1gAMrg9Zt0- >> > s8QqGgZkEoF2CkdpulbYGP40JcJVfPpoc/edit?usp=sharing >> > >> > Best regards, >> > >> > Jakub Golinowski >> >> >> >
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