Puneet, I am familiar with Amdahl’s Law, but I am not familiar with Amdahl IO and cannot find anything with Google. Do you have a reference for this, explaining how it’s computed and what it’s supposed to mean? It is hard to see how the Amdahl’s Law - that speed up from parallelism is limited by the serial portion of a program - has any relationship to the I/O 500 benchmarks, which are concerned with a series of specific and separate benchmarks. The various benchmark numbers are not part of a single parallel program, and so do not have the sort of relationship where Amdahl’s Law is relevant. Regards, Patrick ------------------------------------------------------------------------ *From:* IO-500 <io-500-bounces(a)vi4io.org&gt; on behalf of Puneet Bakshi via IO-500 <io-500(a)vi4io.org&gt; *Sent:* Friday, August 9, 2019 11:11:47 PM *To:* io-500(a)vi4io.org <io-500(a)vi4io.org&gt; *Subject:* [IO-500] Why "Amdahl IO no" is not part of IO500 metric? Dear Sir/Madam, I am Puneet from India and is a student in Indian Institute of Technology Guwahati. I read about IO500 and (Amdahl) Balanced Systems (such as GrayWulf). But, after doing some math, I found some of the top IO500 systems have very low Amdahl IO number. Why IO500 does not include (and publish) Amdahl IO number as one of its metric? Looks like I am missing something but I do not know what. Please help me understand this paradox. This question just came out as an academic curiosity and not to endorse or refute any system. Please help me understand more. Regards, Puneet _______________________________________________ IO-500 mailing list IO-500(a)vi4io.org https://www.vi4io.org/mailman/listinfo/io-500 _______________________________________________ IO-500 mailing list IO-500(a)vi4io.org https://www.vi4io.org/mailman/listinfo/io-500

Adrian, Ah, OK. I'm familiar with the balanced system concept in general, but I wasn't familiar with the specific formalisms (particularly Amdahl's set of rules) described in that slide deck. Thanks! And, yes, I would say I agree with you here - IO500 is specifically an IO subsystem benchmark, not intended to evaluate any other aspect of the system. It could be *combined* with other data, but collecting that other data is outside the intended scope. I'd say this is because how to do that general compute benchmarking is a hugely complex and contentious issue, and also because IO500 is useful specifically because it's bounded in its scope. - Patrick ________________________________ From: JACKSON Adrian <a.jackson(a)epcc.ed.ac.uk&gt; Sent: Saturday, August 10, 2019 11:53:16 AM To: Patrick Farrell <pfarrell(a)whamcloud.com&gt;; Puneet Bakshi <b.puneet(a)iitg.ac.in&gt; Cc: io-500(a)vi4io.org <io-500(a)vi4io.org&gt; Subject: Re: [IO-500] Why "Amdahl IO no" is not part of IO500 metric? Hi Patrick, This is a reasonable intro to the balanced system concept: https://www-conf.slac.stanford.edu/xldb10/docs/xldb4_thu1040_AlexSzalay.pdf I think the answer really is that the IO500 is specifically an I/O metric/benchmark, it's not designed to be a whole system thing. Not to say there isn't merit in collecting whole system data like this, i.e. something like a combined top500/hpcg/streams/io500, it's just not what the io500 was designed for. cheers adrianj On 10/08/2019 17:37, Patrick Farrell via IO-500 wrote: > Puneet, > > I am familiar with Amdahl’s Law, but I am not familiar with Amdahl IO > and cannot find anything with Google. Do you have a reference for this, > explaining how it’s computed and what it’s supposed to mean? It is hard > to see how the Amdahl’s Law - that speed up from parallelism is limited > by the serial portion of a program - has any relationship to the I/O 500 > benchmarks, which are concerned with a series of specific and separate > benchmarks. The various benchmark numbers are not part of a single > parallel program, and so do not have the sort of relationship where > Amdahl’s Law is relevant. > > Regards, > Patrick > ------------------------------------------------------------------------ > *From:* IO-500 <io-500-bounces(a)vi4io.org&gt; on behalf of Puneet Bakshi via > IO-500 <io-500(a)vi4io.org&gt; > *Sent:* Friday, August 9, 2019 11:11:47 PM > *To:* io-500(a)vi4io.org <io-500(a)vi4io.org&gt; > *Subject:* [IO-500] Why "Amdahl IO no" is not part of IO500 metric? > > Dear Sir/Madam, > > I am Puneet from India and is a student in Indian Institute of > Technology Guwahati. > > I read about IO500 and (Amdahl) Balanced Systems (such as GrayWulf). > But, after doing some math, I found some of the top IO500 systems have > very low Amdahl IO number. Why IO500 does not include (and publish) > Amdahl IO number as one of its metric? Looks like I am missing something > but I do not know what. Please help me understand this paradox. This > question just came out as an academic curiosity and not to endorse or > refute any system. Please help me understand more. > > Regards, > Puneet > _______________________________________________ > IO-500 mailing list > IO-500(a)vi4io.org > https://www.vi4io.org/mailman/listinfo/io-500 > > _______________________________________________ > IO-500 mailing list > IO-500(a)vi4io.org > https://www.vi4io.org/mailman/listinfo/io-500 > -- Tel: +44 131 6506470 skype: remoteadrianj The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. _______________________________________________ IO-500 mailing list IO-500(a)vi4io.org https://www.vi4io.org/mailman/listinfo/io-500

Dear Sir(s), Thanks for taking time to provide your comments. Now I understand more. Is it possible that I get to see the discussions happening in this forum or can I be the member of this forum? Regards, Puneet ------------------------------------------------------------------------ *From:* Julian Kunkel <juliankunkel(a)googlemail.com&gt; *Sent:* Sunday, August 11, 2019 12:08:20 AM *To:* Patrick Farrell <pfarrell(a)whamcloud.com&gt; *Cc:* JACKSON Adrian <a.jackson(a)epcc.ed.ac.uk&gt;; Puneet Bakshi <b.puneet(a)iitg.ac.in&gt;; io-500(a)vi4io.org <io-500(a)vi4io.org&gt; *Subject:* Re: [IO-500] Why "Amdahl IO no" is not part of IO500 metric? Hi Puneet, basically, the CDCL collects quite a lot of data for data centers: https://www.vi4io.org/hpsl/start This can be very comprehensive, such as for NERSC: https://www.vi4io.org/hpsl/2019/usa/nersc/start Allowing to do such kind of derived analysis that you mention. The IO-500 supports that people provide an URL to the CDCL. The CDCL will be extended for the IO-500 field, so far the main blocker was that only few people provide the full list of features to CDCL, hence, linking didn't brink too much benefit. If more people would provide the CDCL data, that would accelerate the integration. Best, Julian On Sat, Aug 10, 2019 at 6:10 PM Patrick Farrell via IO-500 <io-500(a)vi4io.org&gt; wrote: > > Adrian, > > > Ah, OK.  I'm familiar with the balanced system concept in general, but I wasn't familiar with the specific formalisms (particularly Amdahl's set of rules) described in that slide deck.  Thanks! > > > And, yes, I would say I agree with you here - IO500 is specifically an IO subsystem benchmark, not intended to evaluate any other aspect of the system.  It could be *combined* with other data, but collecting that other data is outside the intended scope.  I'd say this is because how to do that general compute benchmarking is a hugely complex and contentious issue, and also because IO500 is useful specifically because it's bounded in its scope. > > > - Patrick > > ________________________________ > From: JACKSON Adrian <a.jackson(a)epcc.ed.ac.uk&gt; > Sent: Saturday, August 10, 2019 11:53:16 AM > To: Patrick Farrell <pfarrell(a)whamcloud.com&gt;; Puneet Bakshi <b.puneet(a)iitg.ac.in&gt; > Cc: io-500(a)vi4io.org <io-500(a)vi4io.org&gt; > Subject: Re: [IO-500] Why "Amdahl IO no" is not part of IO500 metric? > > Hi Patrick, > > This is a reasonable intro to the balanced system concept: > > https://www-conf.slac.stanford.edu/xldb10/docs/xldb4_thu1040_AlexSzalay.pdf > > I think the answer really is that the IO500 is specifically an I/O > metric/benchmark, it's not designed to be a whole system thing. > > Not to say there isn't merit in collecting whole system data like this, > i.e. something like a combined top500/hpcg/streams/io500, it's just not > what the io500 was designed for. > > cheers > > adrianj > > On 10/08/2019 17:37, Patrick Farrell via IO-500 wrote: > > Puneet, > > > > I am familiar with Amdahl’s Law, but I am not familiar with Amdahl IO > > and cannot find anything with Google.  Do you have a reference for this, > > explaining how it’s computed and what it’s supposed to mean?  It is hard > > to see how the Amdahl’s Law - that speed up from parallelism is limited > > by the serial portion of a program - has any relationship to the I/O 500 > > benchmarks, which are concerned with a series of specific and separate > > benchmarks.  The various benchmark numbers are not part of a single > > parallel program, and so do not have the sort of relationship where > > Amdahl’s Law is relevant. > > > > Regards, > > Patrick > > ------------------------------------------------------------------------ > > *From:* IO-500 <io-500-bounces(a)vi4io.org&gt; on behalf of Puneet Bakshi via > > IO-500 <io-500(a)vi4io.org&gt; > > *Sent:* Friday, August 9, 2019 11:11:47 PM > > *To:* io-500(a)vi4io.org <io-500(a)vi4io.org&gt; > > *Subject:* [IO-500] Why "Amdahl IO no" is not part of IO500 metric? > > > > Dear Sir/Madam, > > > > I am Puneet from India and is a student in Indian Institute of > > Technology Guwahati. > > > > I read about IO500 and (Amdahl) Balanced Systems (such as GrayWulf). > > But, after doing some math, I found some of the top IO500 systems have > > very low Amdahl IO number. Why IO500 does not include (and publish) > > Amdahl IO number as one of its metric? Looks like I am missing something > > but I do not know what. Please help me understand this paradox. This > > question just came out as an academic curiosity and not to endorse or > > refute any system. Please help me understand more. > > > > Regards, > > Puneet > > _______________________________________________ > > IO-500 mailing list > > IO-500(a)vi4io.org > > https://www.vi4io.org/mailman/listinfo/io-500 > > > > _______________________________________________ > > IO-500 mailing list > > IO-500(a)vi4io.org > > https://www.vi4io.org/mailman/listinfo/io-500 > > > > -- > Tel: +44 131 6506470 skype: remoteadrianj > The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. > _______________________________________________ > IO-500 mailing list > IO-500(a)vi4io.org > https://www.vi4io.org/mailman/listinfo/io-500 -- Dr. Julian Kunkel Lecturer, Department of Computer Science +44 (0) 118 378 8218 http://www.cs.reading.ac.uk/ https://hps.vi4io.org/ PGP Fingerprint: 1468 1A86 A908 D77E B40F 45D6 2B15 73A5 9D39 A28E _______________________________________________ IO-500 mailing list IO-500(a)vi4io.org https://www.vi4io.org/mailman/listinfo/io-500