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Message boards : Number crunching : Multithreading?

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Miklos M.
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Joined: 14 Apr 12
Posts: 320
ID: 138455
Credit: 6,344,825,257
RAC: 8,991,047
Discovered 1 mega prime321 LLR Amethyst: Earned 1,000,000 credits (1,761,944)Cullen LLR Gold: Earned 500,000 credits (800,070)ESP LLR Amethyst: Earned 1,000,000 credits (1,357,780)PPS LLR Turquoise: Earned 5,000,000 credits (5,363,728)PSP LLR Silver: Earned 100,000 credits (113,391)SoB LLR Gold: Earned 500,000 credits (651,117)SR5 LLR Amethyst: Earned 1,000,000 credits (1,373,362)SGS LLR Amethyst: Earned 1,000,000 credits (1,258,223)TRP LLR Amethyst: Earned 1,000,000 credits (1,834,433)Woodall LLR Gold: Earned 500,000 credits (624,562)321 Sieve Jade: Earned 10,000,000 credits (13,484,557)Cullen/Woodall Sieve (suspended) Ruby: Earned 2,000,000 credits (4,036,945)Generalized Cullen/Woodall Sieve (suspended) Emerald: Earned 50,000,000 credits (83,631,931)PPS Sieve Double Turquoise: Earned 5,000,000,000 credits (6,072,175,558)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Sapphire: Earned 20,000,000 credits (46,622,519)TRP Sieve (suspended) Sapphire: Earned 20,000,000 credits (32,704,392)AP 26/27 Sapphire: Earned 20,000,000 credits (30,670,198)GFN Sapphire: Earned 20,000,000 credits (46,397,627)
Message 131797 - Posted: 7 Aug 2019 | 14:39:45 UTC

Could anyone using multithreading give me some suggestions on how to apply it to this computer?

GenuineIntel
Intel(R) Core(TM) i9-9980XE CPU @ 3.00GHz [Family 6 Model 85 Stepping 4]
(36 processors) [3] NVIDIA GeForce RTX 2080 Ti (4095MB) driver: 43040

Thank you

Profile Rafael
Volunteer tester
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Joined: 22 Oct 14
Posts: 855
ID: 370496
Credit: 294,768,112
RAC: 88,687
321 LLR Turquoise: Earned 5,000,000 credits (6,245,917)Cullen LLR Turquoise: Earned 5,000,000 credits (6,157,856)ESP LLR Turquoise: Earned 5,000,000 credits (5,478,853)Generalized Cullen/Woodall LLR Turquoise: Earned 5,000,000 credits (5,261,102)PPS LLR Turquoise: Earned 5,000,000 credits (6,157,070)PSP LLR Turquoise: Earned 5,000,000 credits (6,252,934)SoB LLR Turquoise: Earned 5,000,000 credits (5,783,115)SR5 LLR Turquoise: Earned 5,000,000 credits (5,463,607)SGS LLR Turquoise: Earned 5,000,000 credits (5,071,454)TRP LLR Turquoise: Earned 5,000,000 credits (5,007,966)Woodall LLR Turquoise: Earned 5,000,000 credits (6,013,272)321 Sieve Amethyst: Earned 1,000,000 credits (1,274,050)Generalized Cullen/Woodall Sieve (suspended) Jade: Earned 10,000,000 credits (10,037,204)PPS Sieve Jade: Earned 10,000,000 credits (10,305,147)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Ruby: Earned 2,000,000 credits (2,000,053)TRP Sieve (suspended) Ruby: Earned 2,000,000 credits (2,030,160)AP 26/27 Jade: Earned 10,000,000 credits (10,253,048)GFN Sapphire: Earned 20,000,000 credits (25,217,853)PSA Double Bronze: Earned 100,000,000 credits (170,758,062)
Message 131800 - Posted: 7 Aug 2019 | 15:48:30 UTC - in response to Message 131797.

(I'm assuming you want suggestions for how many cores to use on each task, as instructions to how to set it up are easily found on the challenge thread).

First, before setting up MT (or doing anything, for that mater), get a better cooler.

No, your current one is not enough to handle 18 AVX512 cores at high frequency, whatever it may be... to be honest, nothing really is.


Anyway, depends on what project you want to run. For SGS and PPS, running without MT is usually better. PPS-MEGA has some debate, but my personal preference is to run 1 per core.

For bigger things, you want to try and fit all of the WU inside the cache to maximize performance. Look up the FFT size of each project (I would link it, but I'm on mobile right now) and multiply by 8; that's how much cache you "need", see how many cores you need to fit that and go from there. Say, imagine ESP takes 5ish mb, give it 6 of your 18 cores and run 3 tasks at the same time. Or give it 5 and run 4, rellying on your RAM to make up the slack - test it to see what works better.

Also consider leaving a core or 2 free for your GPU, depending on the aboce and what you intend to do with it.



Oh yeah, and before I forget, turn off HT if you can.

rjs5
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Joined: 20 Feb 11
Posts: 34
ID: 87238
Credit: 434,705,532
RAC: 712,106
Discovered 3 mega primes321 LLR Jade: Earned 10,000,000 credits (10,244,140)Cullen LLR Jade: Earned 10,000,000 credits (10,216,859)ESP LLR Jade: Earned 10,000,000 credits (10,191,519)Generalized Cullen/Woodall LLR Turquoise: Earned 5,000,000 credits (5,977,145)PPS LLR Turquoise: Earned 5,000,000 credits (9,673,516)PSP LLR Turquoise: Earned 5,000,000 credits (7,571,847)SoB LLR Jade: Earned 10,000,000 credits (10,297,183)SR5 LLR Turquoise: Earned 5,000,000 credits (5,547,645)SGS LLR Turquoise: Earned 5,000,000 credits (6,503,220)TRP LLR Turquoise: Earned 5,000,000 credits (5,235,544)Woodall LLR Turquoise: Earned 5,000,000 credits (5,354,915)321 Sieve Turquoise: Earned 5,000,000 credits (5,202,086)Cullen/Woodall Sieve (suspended) Gold: Earned 500,000 credits (879,677)Generalized Cullen/Woodall Sieve (suspended) Turquoise: Earned 5,000,000 credits (5,273,914)PPS Sieve Emerald: Earned 50,000,000 credits (60,304,021)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Turquoise: Earned 5,000,000 credits (5,437,484)TRP Sieve (suspended) Turquoise: Earned 5,000,000 credits (5,509,929)AP 26/27 Sapphire: Earned 20,000,000 credits (23,000,627)GFN Double Silver: Earned 200,000,000 credits (206,758,404)PSA Sapphire: Earned 20,000,000 credits (35,533,950)
Message 131803 - Posted: 7 Aug 2019 | 17:08:35 UTC - in response to Message 131797.

Could anyone using multithreading give me some suggestions on how to apply it to this computer?

GenuineIntel
Intel(R) Core(TM) i9-9980XE CPU @ 3.00GHz [Family 6 Model 85 Stepping 4]
(36 processors) [3] NVIDIA GeForce RTX 2080 Ti (4095MB) driver: 43040

Thank you


I am running he same machine, but with just one 2080 Ti Founders Edition, Fedora and the best cooler I could buy.

I set the BIOS CPU temperature limit to 75 degrees.
Nvidia vents the hot air out the TOP of the 2080 Ti FE instead of the REAR like previous designs. Be aware of where the 2080 Ti boards dispose of their heat. The 2080 Ti runs at 80% centigrade on most of the PG GPU WU.

I set BOINC to run five llr321 WU with 4-threads. The "top" command indicates each WU is using about 370% CPU or somewhat less than 4 since there is some overhead in synchronizing the threads. The instructions per cycle have dropped from 1.8 to 1.3, so I am pretty close to a "good" number. I did this by setting the CPU PREFERENCES to 60%.

After you get to somewhere about 40% CPUs used, the SW prefetch instructions exhaust the MEMORY FILL BUFFERS and any more WU will simply stall waiting for memory buffer. I have never bothered turning off HT and am not sure how much difference that will make over all the CPU, system and OS variations.

The clip from Intel Vtune Amplifier instrumentation shows where in the code LLR is stalling. You can see that it is spending its life waiting on the prefetcht0z instructions waiting for a fill buffer. My problem with the SW prefetch instructions is ... they are easy to add to code, but everyone then assumes that they still make sense and leave them in.


0x19b2325 0 vaddpd %zmm18, %zmm16, %zmm16 1.0 15,000,000
0x19b232b 0 prefetcht0z (%r12) 1.5 45,000,000
0x19b2330 0 vsubpd %zmm19, %zmm17, %zmm18 27.5 735,000,000
0x19b2336 0 vaddpd %zmm19, %zmm17, %zmm17
0x19b233c 0 prefetcht0z 0x40(%r12)
0x19b2342 0 vsubpd %zmm23, %zmm21, %zmm19 29.5 675,000,000
0x19b2348 0 vaddpd %zmm23, %zmm21, %zmm21 1.0 45,000,000
0x19b234e 0 prefetcht0z (%r12,%r8,1) 1.0 -
0x19b2353 0 vsubpd %zmm20, %zmm22, %zmm23 23.5 300,000,000
0x19b2359 0 vaddpd %zmm20, %zmm22, %zmm22 1.0 30,000,000
0x19b235f 0 prefetcht0z 0x40(%r12,%r8,1) 1.0 15,000,000
0x19b2365 0 vaddpd %zmm13, %zmm24, %zmm20 23.5 375,000,000
0x19b236b 0 vsubpd %zmm13, %zmm24, %zmm24 0.5 45,000,000
0x19b2371 0 prefetcht0z (%r12,%r8,2) 0.5 15,000,000
0x19b2376 0 vaddpd %zmm14, %zmm15, %zmm13 24.5 225,000,000
0x19b237c 0 vsubpd %zmm14, %zmm15, %zmm15 1.0 15,000,000
0x19b2382 0 prefetcht0z 0x40(%r12,%r8,2) 0.5 -
0x19b2388 0 vsubpd %zmm7, %zmm6, %zmm14 20.0 495,000,000
0x19b238e 0 vaddpd %zmm7, %zmm6, %zmm6 1.0 -
0x19b2394 0 prefetcht0z (%r12,%r10,1) 0.5 30,000,000
0x19b2399 0 vsubpd %zmm4, %zmm18, %zmm7 21.0 225,000,000
0x19b239f 0 vaddpd %zmm18, %zmm4, %zmm4
0x19b23a5 0 prefetcht0z 0x40(%r12,%r10,1) 0.5 60,000,000
0x19b23ab 0 vsubpd %zmm19, %zmm23, %zmm18 26. 210,000,000
0x19b23b1 0 vaddpd %zmm23, %zmm19, %zmm19 0.5 45,000,000
0x19b23b7 0 prefetcht0z (%r14) 0.0 45,000,000
0x19b23bb 0 vaddpd %zmm5, %zmm25, %zmm23 21.5 210,000,000
0x19b23c1 0 vsubpd %zmm5, %zmm25, %zmm25 0.5 60,000,000








Miklos M.
Send message
Joined: 14 Apr 12
Posts: 320
ID: 138455
Credit: 6,344,825,257
RAC: 8,991,047
Discovered 1 mega prime321 LLR Amethyst: Earned 1,000,000 credits (1,761,944)Cullen LLR Gold: Earned 500,000 credits (800,070)ESP LLR Amethyst: Earned 1,000,000 credits (1,357,780)PPS LLR Turquoise: Earned 5,000,000 credits (5,363,728)PSP LLR Silver: Earned 100,000 credits (113,391)SoB LLR Gold: Earned 500,000 credits (651,117)SR5 LLR Amethyst: Earned 1,000,000 credits (1,373,362)SGS LLR Amethyst: Earned 1,000,000 credits (1,258,223)TRP LLR Amethyst: Earned 1,000,000 credits (1,834,433)Woodall LLR Gold: Earned 500,000 credits (624,562)321 Sieve Jade: Earned 10,000,000 credits (13,484,557)Cullen/Woodall Sieve (suspended) Ruby: Earned 2,000,000 credits (4,036,945)Generalized Cullen/Woodall Sieve (suspended) Emerald: Earned 50,000,000 credits (83,631,931)PPS Sieve Double Turquoise: Earned 5,000,000,000 credits (6,072,175,558)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Sapphire: Earned 20,000,000 credits (46,622,519)TRP Sieve (suspended) Sapphire: Earned 20,000,000 credits (32,704,392)AP 26/27 Sapphire: Earned 20,000,000 credits (30,670,198)GFN Sapphire: Earned 20,000,000 credits (46,397,627)
Message 131805 - Posted: 7 Aug 2019 | 18:05:07 UTC - in response to Message 131803.

Thank you for the answer.

Miklos M.
Send message
Joined: 14 Apr 12
Posts: 320
ID: 138455
Credit: 6,344,825,257
RAC: 8,991,047
Discovered 1 mega prime321 LLR Amethyst: Earned 1,000,000 credits (1,761,944)Cullen LLR Gold: Earned 500,000 credits (800,070)ESP LLR Amethyst: Earned 1,000,000 credits (1,357,780)PPS LLR Turquoise: Earned 5,000,000 credits (5,363,728)PSP LLR Silver: Earned 100,000 credits (113,391)SoB LLR Gold: Earned 500,000 credits (651,117)SR5 LLR Amethyst: Earned 1,000,000 credits (1,373,362)SGS LLR Amethyst: Earned 1,000,000 credits (1,258,223)TRP LLR Amethyst: Earned 1,000,000 credits (1,834,433)Woodall LLR Gold: Earned 500,000 credits (624,562)321 Sieve Jade: Earned 10,000,000 credits (13,484,557)Cullen/Woodall Sieve (suspended) Ruby: Earned 2,000,000 credits (4,036,945)Generalized Cullen/Woodall Sieve (suspended) Emerald: Earned 50,000,000 credits (83,631,931)PPS Sieve Double Turquoise: Earned 5,000,000,000 credits (6,072,175,558)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Sapphire: Earned 20,000,000 credits (46,622,519)TRP Sieve (suspended) Sapphire: Earned 20,000,000 credits (32,704,392)AP 26/27 Sapphire: Earned 20,000,000 credits (30,670,198)GFN Sapphire: Earned 20,000,000 credits (46,397,627)
Message 131806 - Posted: 7 Aug 2019 | 18:06:25 UTC - in response to Message 131797.

Thank you for the reply.

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Message boards : Number crunching : Multithreading?

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