Can extra processing threads help in this case?
in [MFC]
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From: Pete Delgado on 22 Mar 2010 16:53 "Joseph M. Newcomer" <newcomer(a)flounder.com> wrote in message news:9qkfq51noaiib6evaqnkp4jngbnhgr3b67(a)4ax.com... >I have a NUMA machine, and AMD dual-chip dual-core (4-core) system running >WIn32 (Vista), > so if you need some tests run, email the code to me. > > Remember when he wanted his data allocating in CONTIGUOUS PHYSICAL memory? > He is really > clueless about how operating systems work, but won't listen to ANYONE > whose ideas don't > match his preconceived notions about how the world should work to maximize > his > convenience. EVen if what we're trying to do is explain how reality > works. Joe, The amzing thing to me is the incredible amount of patience you have had with Mr. Olcott. You have referenced Richter's book which would explain everything he needs to know in a few short pages and yet he has resisted. I've been reading this thread with a combination of amusement and bewilderment. I guess the old adage that "you can lead a horse to water, but you cannot make him drink" has never been more appropriate. :-) -Pete
From: Pete Delgado on 22 Mar 2010 17:10 "Peter Olcott" <NoSpam(a)OCR4Screen.com> wrote in message news:osWdnaGZ3q06RTrWnZ2dnUVZ_uudnZ2d(a)giganews.com... > > "Joseph M. Newcomer" <newcomer(a)flounder.com> wrote in message > news:ecdfq5lb57qrou47d1ppaupsi6t2guu7nv(a)4ax.com... >> **** >> He has NO CLUE as to what a "memory-mapped file" actually is. This last >> comment indicates > > http://en.wikipedia.org/wiki/Memory-mapped_file > Apparently I do. I think you would be far better served by looking at Windows specific information on memory mapped files such as that which Joe suggested to you some time ago: Richter's Programming Applications for Microsoft Windows 4th. -Pete
From: Joseph M. Newcomer on 22 Mar 2010 17:13 Or, as we used to say when I was University faculty: "You can lead a student to knowledge, but you can't make him think" I got a lot of flack when I gave an examine that required students USE the knowledge I'd given them for the last two weeks, plus the knowledge they would have gained from doing the homework assignment. Because they couldn't do a "memory dump" from my PowerPoint slides, they thought the test "unfair". joe On Mon, 22 Mar 2010 16:53:51 -0400, "Pete Delgado" <Peter.Delgado(a)NoSpam.com> wrote: > >"Joseph M. Newcomer" <newcomer(a)flounder.com> wrote in message >news:9qkfq51noaiib6evaqnkp4jngbnhgr3b67(a)4ax.com... >>I have a NUMA machine, and AMD dual-chip dual-core (4-core) system running >>WIn32 (Vista), >> so if you need some tests run, email the code to me. >> >> Remember when he wanted his data allocating in CONTIGUOUS PHYSICAL memory? >> He is really >> clueless about how operating systems work, but won't listen to ANYONE >> whose ideas don't >> match his preconceived notions about how the world should work to maximize >> his >> convenience. EVen if what we're trying to do is explain how reality >> works. > >Joe, >The amzing thing to me is the incredible amount of patience you have had >with Mr. Olcott. You have referenced Richter's book which would explain >everything he needs to know in a few short pages and yet he has resisted. >I've been reading this thread with a combination of amusement and >bewilderment. I guess the old adage that "you can lead a horse to water, but >you cannot make him drink" has never been more appropriate. :-) > >-Pete > > Joseph M. Newcomer [MVP] email: newcomer(a)flounder.com Web: http://www.flounder.com MVP Tips: http://www.flounder.com/mvp_tips.htm
From: Joseph M. Newcomer on 22 Mar 2010 17:21 No, you are the one stuck in "refute mode". I keep insisting that the ONLY way you can refute what we are saying is by running the actual experiment, and you keep saying, no, you KNOW that it will fail. Without data, you have no way to validly assert this. joe On Mon, 22 Mar 2010 15:25:59 -0500, "Peter Olcott" <NoSpam(a)OCR4Screen.com> wrote: > >"Hector Santos" <sant9442(a)nospam.gmail.com> wrote in message >news:ea3d0gfyKHA.5040(a)TK2MSFTNGP02.phx.gbl... >> Peter Olcott wrote: >> >>> Try and explain exactly how cache can possibly help when >>> there is most often essentially no spatial or temporal >>> locality of reference. >> >> >> Its called WINDOWS Virtual Memory Caching technology. >> >> This is not DOS. You are not dealing directly with the >> CHIP here. > >I know that. I also know the inherent memory access patterns >of my algorithm. > >Joe keeps bringing up how complex the actual underlying >memory access patterns are when one also considers cache. > >I keep brining up that there can be no complex underlying >memory access patterns if because of lack of spatial and >temporal locality of reference cache can mostly not be used. > >I am beginning to think you two guys are stuck in "refute >mode", yet I remain open to the possibility that it may be >me and neither of you. > >> >> You need to stop reading stuff out, finding a new "buzz >> word" thinking you got a "AH HA" and believe it proves >> your erroneous understanding of Windows programming. >> >> -- >> HLS > Joseph M. Newcomer [MVP] email: newcomer(a)flounder.com Web: http://www.flounder.com MVP Tips: http://www.flounder.com/mvp_tips.htm
From: Joseph M. Newcomer on 22 Mar 2010 17:24
See below... On Mon, 22 Mar 2010 15:47:46 -0500, "Peter Olcott" <NoSpam(a)OCR4Screen.com> wrote: > >"Joseph M. Newcomer" <newcomer(a)flounder.com> wrote in >message news:rnjfq5ls8fpma0kvrc6odhuvqfignso8m5(a)4ax.com... >> See below... >> On Mon, 22 Mar 2010 14:40:57 -0500, "Peter Olcott" >> <NoSpam(a)OCR4Screen.com> wrote: >> >> >>> >>>Try and explain exactly how cache can possibly help when >>>there is most often essentially no spatial or temporal >>>locality of reference. >>> >> **** >> While caches work well with locality of reference, that is >> just a heuristic for predicting >> cache effects. Locality of reference is not the point; >> maximizing cache hits is the >> point. And this can happen, particularly on a shared L3 >> cache, based solely on the cache >> replacement algorithm. We use locality of reference as >> the "easy" approach to determining >> the likelikhood of cache hits, because it is easy to >> analyze in applications that process >> regular data like matrices and arrays. But it is not the >> theoretical optimum approach. If >> you took the time to understand how caches work this would >> be obvious to you. >> >> Try to explain why you believe this when you have run no >> experiments that have any >> meaning. The difference is that I am saying YOU HAVE NO >> DATA, and you are saying I KNOW >> WHAT IS GOING TO HAPPEN, I DON'T NEED NO STINKIN' FACTS. >> I don't believe you really know > >I do have data, and present this data many times and you two >simply blow it off. >Two processes take 2.75 times as long as one process. What >could this mean besides resource contention? *** An what does a two-process measure tell you about multithreading? NOTHING! You have a flawed experiment that is generalizing from the wrong premises. OF COURSE two huge processes are going to have resource contention! And are these running on a single core or multicore machine? But multiple threads have signficant lower resource conention, and you ignore this fact and think your two-process model is the absolute authoritative experiment. I'd never trust data like this, and if I were a product manager I'd send you back to get real data. You are your own product manager, and should recognize (give how much we've told you) and you should send yourself back to get valid data. joe > >You tell me all about pages faults, yet the process monitor >reports zero page faults, and you continue to claim that its >all about page faults, and virtual memory. Pages faults >indicate victual memory usage right? A lack of page faults >indicates a lack of virtual memory usage right? > >> what is going to happen, you are just guessing. I know >> what I would do: as an egineer >> (there's that nasty word again) I'd go out at GET the >> facts. Then, I could say "But I >> have run this experiment, and it substantiates my theory" >> and that would be useful >> knowledge. But you just blindly claim you "know" what is >> going to happen. I'` `m supposed >> to take this seriously from someone who dosen't even >> understand why a Memory Mapped File >> is going to give superior performance? Given your >> demonstrated lack of understanding of >> operating systems, why should I believe ANY assertion you >> make, unless you have the data >> to back it up? Hell, I wouldn't believe MY OWN theories >> about performance without data, >> and 15 years of performance measurement have convinced me >> of one absolute fact: "Ask a >> programmer when the performance bottleneck is in their >> code, and you will get a wrong >> answer". That rule NEVER failed me in 15 years of real >> performance measurement of real >> programs on real machines, and I believe it today. Botom >> line: only actual performance >> data proves anything. Theories about where performance is >> going are universally wrong >> unless supported by actual measurements. You have a >> p-baked theory, for p considerably >> less than 0.5 (p==0.5 is half-baked), and you refuse to >> see test your theory. Not a >> robust approach to building systems. You may be >> absolutely correct, but you cannot PROVE >> it without data. >> joe >> **** >> >>>>> >>>> Joseph M. Newcomer [MVP] >>>> email: newcomer(a)flounder.com >>>> Web: http://www.flounder.com >>>> MVP Tips: http://www.flounder.com/mvp_tips.htm >>> >> Joseph M. Newcomer [MVP] >> email: newcomer(a)flounder.com >> Web: http://www.flounder.com >> MVP Tips: http://www.flounder.com/mvp_tips.htm > Joseph M. Newcomer [MVP] email: newcomer(a)flounder.com Web: http://www.flounder.com MVP Tips: http://www.flounder.com/mvp_tips.htm |