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Aurum
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Re: For Current Volunteers: Advance Information on Our Newest Project

That's to be expected.
Not by over 2x it's not.
Even if you set BOINC to half the possible threads with HT on you will observe faster processing, at least I do on my machine with W10.
I tried that but halfing the number of WUs speeds them up by not even close to 2x.
Nothing needed to be hyperthreaded.
Huh???
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Re: For Current Volunteers: Advance Information on Our Newest Project

Well, it's close to 2x faster on my W10, with HT on and half the threads, or differently running in close to half the time, but if you want to split hairs. Maybe your Linux needs tuning.

"That's to be expected", see Jim's last sentence of the expanded explanation ;o)
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Aurum
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Re: For Current Volunteers: Advance Information on Our Newest Project

Look forward to seeing your data.
This old article explains the issues that can adversely impact multithreaded processing. https://software.intel.com/content/www/us/en/...ms.html?wapkw=smart+cache
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[Edit 1 times, last edit by Aurum420 at Aug 23, 2020 2:38:25 PM]
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Aurum
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Re: For Current Volunteers: Advance Information on Our Newest Project

arp1 23.19
arp1 22.76
arp1 22.73
arp1 22.53
arp1 22.50
arp1 22.46
arp1 22.42
arp1 22.39
arp1 22.36
arp1 22.35
arp1 22.33
arp1 22.29
arp1 22.10
arp1 22.00
arp1 21.95
arp1 21.83
arp1 21.65
arp1 19.81
arp1 10.10
arp1 10.09
arp1 10.03
arp1 9.96
arp1 9.76
arp1 9.40
Average with HT = 22.20 hours
Average sans HT = 9.89 hours
i9-9960X with one CPU for the GPU & running only ARP WUs.
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Sgt.Joe
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Re: For Current Volunteers: Advance Information on Our Newest Project

Based on those figures you are getting more work done with HT off than on. Without a deeper dive into the ins and outs of the how the ARP units are processed, I would not know why this happens. And, I am not qualified to do the deeper dive.
Cheers
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Jim1348
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Re: For Current Volunteers: Advance Information on Our Newest Project

Well, it's close to 2x faster on my W10, with HT on and half the threads, or differently running in close to half the time, but if you want to split hairs. Maybe your Linux needs tuning.

"That's to be expected", see Jim's last sentence of the expanded explanation ;o)

You miss the point. You are running too many work units at once with HT on. That isn't a problem with HT. It is exceeding the available cache.
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Aurum
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Re: For Current Volunteers: Advance Information on Our Newest Project

Based on those figures you are getting more work done with HT off than on.

Average with HT = 22.20 hours
Average sans HT = 9.89 hours
Throughput:
24 hr/day x 31 CPUs/computer ÷ 22.20 CPU-hr/WU = 33.5 WU/computer-day
24 hr/day x 15 CPUs/computer ÷ 9.89 CPU-hr/WU = 36.4 WU/computer-day
That's 9% more work done each day with HT disabled. I thought it was common wisdom that running with hyperthreading leads to 15% more throughput.
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Aurum
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Re: For Current Volunteers: Advance Information on Our Newest Project

You are running too many work units at once with HT on.
That should not be possible unless it's improperly coded for multithreading and use of the cache. The only two BOINC projects I know of with that problem are MIP & ARP. MIP uses Rosetta but the Baker Lab at UW has upgraded Rosetta and solved this problem with their WUs. MIP can cure this when they chose to upgrade Rosetta. I'm suggesting that ARP programmers need to debug their code to make it efficient.
That isn't a problem with HT. It is exceeding the available cache.
The CPU is designed with 3 levels of cache to enable hyperthreading. The program needs to make use of the hardware properly.
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[Edit 1 times, last edit by Aurum420 at Aug 24, 2020 7:14:35 PM]
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Jim1348
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Re: For Current Volunteers: Advance Information on Our Newest Project

You are running too many work units at once with HT on.
That should not be possible unless it's improperly coded for multithreading and use of the cache. The only two BOINC projects I know of with that problem are MIP & ARP.

CPDN has the problem with some of their work units. Anything that uses a lot of cache can be a problem. You can say that they shouldn't have the problem if you want to. But that is irrelevant to the point of understanding how HT works.

PS - Insofar as I know the OS decides what goes in what cache. All the programmer can do is limit the amount of writes to memory. Some programs are better at that than others. Maybe there are other tricks. But in the end, all the crunchers can do is check to see if we are getting a slowdown with multiple work units. The cure is to limit the number (as with an app_config.xml), not turn off HT.
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[Edit 1 times, last edit by Jim1348 at Aug 24, 2020 9:35:11 PM]
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Aurum
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Re: For Current Volunteers: Advance Information on Our Newest Project

Is it possible with arp1 to become a Lone Ranger??? I've yet to make the cut:
Minimum Quorum: 2 & Replication: 2
I wonder if IBM staff will ever answer my question. I've yet to see a Quorum One yet and my Results Status has 180 ARP Pending Validation, 195 Valid & 375 In Progress. I surmise the answer is no there will never be Quorum One status for ARP but it would be nice to understand why.
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[Edit 1 times, last edit by Aurum420 at Aug 30, 2020 2:13:20 PM]
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