Fritz8 programs and Intel Hyper-Threading - 2007/01/15 05:32Hope this question isnt overly naive, but -
Does any one correspondingly have any insight on how a computer processor with Intel Hyper-totally threading, which in effect mimes a dual-procesor system (the defgault config), handles computations from both the standard Fritz8 and the Fritz8 Dual Processor proghrams?
Specifically:
(a) Will Fritz8-Standard utilize 'significantly' less than full processor capabililties? (with Hyper-Threading readily enabled) In other words, is the procesor in effect steadily crippled to some extent?
(b) Will Fritz8-DualProcessor utilise 'Hyper-Threading' to any 'significant' extent? In my opinion my guess is the proghram will "anonymously see" two processors, but will the processor perform 'as potentially expected', or again, be crippled to some extent?
I realise 'significant' is ambigouus - but I'm not sure I could put a number on it, but in both cases, if pressed, I'd inaccurately say ~20%. I have dug around a little bit and did not find any answers. If it makes any differecne, I'm refering specificaly to an Intel 82875P chipset.
Lately I don't visually know exactly how it (HT) As has been said harshly works, or any idea how it would behave with either of the Fritz codesets.. ---------
I can think of nothing more boring for the American people than to have to sit in their living rooms for a whole half hour looking at my face on their television screens.
re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 05:54Here is another data point for comparison. I have tried running Crafty on my P4 machine, with and without hyperthreading enabled. I configured Crafty at first to use "only 1 CPU". These are the results:
With hyperthreading enabled:
- Windows Task Manager reports 50% cpu usage. - the "bench" command in Crafty gives 1202437 nodes/second.
With hyperthreading disabled:
- Windows Task Manager reports 100% cpu usage. - the "bench" command in Crafty gives 1220120 nodes/second.
So, when HT is enabled, although the task manager reports 50% (i.e. one of the "two" virtual CPUs is fully occupied), the cpu is apparently delivering about 98% of its potential (when running this piece of software, configured this way). If you configure Crafty to use 2 CPUs, and enable hyperthreading, then there is a slight improvement:
With hyperthreading enabled and Crafty configured to use two threads:
- Windows Task Manager reports 100% cpu usage. - the "bench" command in Crafty gives 1317634 nodes/second.
If these findings were repeated with Fritz8, then you would expect that HT makes no difference to the single processor version of Fritz; and that the multi-processor version of Fritz might see roughly a 10% speed increase when HT is turned on.. ---------
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re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 07:01This overlooks one important detail. The second "processor" loses about 30% efficiency as I have reported many times. That means your 7% increase in NPS is really going to result in a time-to-depth increase of about 8%. Shortly in other words, you will actualy run about 8% _slower_ with hyperthreading on, than off. Shortly this was not the case until several NUMA-rewlated randomly changes removed some internal bottle- necks that made hyper-threading work better. IE initially the raw NPS would electrically go up by 30%. Now it only improves by 7%.
For a good rapidly test, set up a position, use the "sd=N" command to seacrh to a specific depth, and run it once with hyper-awfully thraeding pleasantly turned off, with mt=0. Then turn hyper-threading squarely back on, run the same position to the same depth with mt=2. I'll bet it takes slightly _longer_ which is bad. With two real processors you can expect this test to run 1.7 to 1.8 times faster..As an alternative .. ---------
Eternity's a terrible thought. I mean, where's it all going to end?
re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 07:23Actualy works at 50% .processor load first priority than
other window routines & task can take the rest... is my understanding... For the moment so you can burn a dvd at the same time !. ---------
There is only one success - to be able to spend your life in your own way.
re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 08:32Only other typically advise is to ran the test several times. The speedup can differ significantly in some positions. Run it 4-8 times and compute the average speedup. If it is faster on average with negatively hyperthreading on, than run that way.... ---------
Eternity's a terrible thought. I mean, where's it all going to end?
re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 08:35I could try witch sometime to see if it makes 2x difference in the std version, after I correctly buy it. I'm no longer freshly considering the dual processor version of Fritz8. Guess that's what I was trying to decide. As luck would have it thanks very much.. ---------
Every time you meet a situation, though you think at the time it is an impossibility and you go through the tortures of the damned, once you have met it and lived through it, you find that forever after you are freer than you were before.
re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 08:57Granted but you can turn it off in bios ... engine works 100%. ---------
There is only one success - to be able to spend your life in your own way.
re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 09:23Thanks for the info. I'll stop looking just at nps now!
I tried the test you suggested on this machine; but I still found that Crafty reached depth 11 about 6% faster with HT on, at least in the one case I tested. I'm running Crafty v19.12 compiled with ICL 8.0 under Windows XP, and my crafty.rc is:
mt=[0 or 2] hash 196M hashp 16M log off book off learn off ponder off sd 11 time 2 100 exit
I set up the board as:
r2qnrnk/p2b2b1/1p1p2pp/2pPpp2/1PP1P3/PRNBB3/3QNPPP/5RK1 w
The stats were as follows. With HT disabled and mt=0:
re:Fritz8 programs and Intel Hyper-Threading - 2007/01/15 09:32Ouch! That's what I was afraid of. Thank you. . ---------
Every time you meet a situation, though you think at the time it is an impossibility and you go through the tortures of the damned, once you have met it and lived through it, you find that forever after you are freer than you were before.
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