PrimeGrid
Please visit donation page to help the project cover running costs for this month

Toggle Menu

Join PrimeGrid

Returning Participants

Community

Leader Boards

Results

Other

drummers-lowrise

Advanced search

Message boards : Number crunching : How are multi-threading recommendations determined?

Author Message
ZachProject donor
Send message
Joined: 3 May 18
Posts: 24
ID: 1010731
Credit: 42,261,938
RAC: 4,787
Found 2 primes in the 2022 Tour de Primes321 LLR Gold: Earned 500,000 credits (509,620)Cullen LLR Silver: Earned 100,000 credits (142,330)ESP LLR Silver: Earned 100,000 credits (119,149)Generalized Cullen/Woodall LLR Silver: Earned 100,000 credits (285,681)PPS LLR Amethyst: Earned 1,000,000 credits (1,491,983)PSP LLR Silver: Earned 100,000 credits (278,238)SoB LLR Gold: Earned 500,000 credits (504,136)SR5 LLR Gold: Earned 500,000 credits (664,205)SGS LLR Silver: Earned 100,000 credits (101,580)TRP LLR Silver: Earned 100,000 credits (353,161)Woodall LLR Silver: Earned 100,000 credits (301,920)321 Sieve (suspended) Silver: Earned 100,000 credits (170,768)Generalized Cullen/Woodall Sieve (suspended) Silver: Earned 100,000 credits (123,417)PPS Sieve Ruby: Earned 2,000,000 credits (4,083,300)AP 26/27 Ruby: Earned 2,000,000 credits (2,433,886)GFN Jade: Earned 10,000,000 credits (14,866,864)WW Jade: Earned 10,000,000 credits (15,828,000)
Message 153091 - Posted: 6 Jan 2022 | 22:09:49 UTC

1) See title. I'm nerdy-curious why MT isn't recommended for some subprojects.

2) If not answered by 1), what are the risks/challenges/cons to using MT on subproject tasks for which it's NOT recommended?

Profile NickProject donor
Avatar
Send message
Joined: 11 Jul 11
Posts: 2075
ID: 105020
Credit: 7,861,016,739
RAC: 3,732,423
Discovered 9 mega primesFound 5 primes in the 2020 Tour de PrimesFound 2 mega primes in the 2020 Tour de PrimesFound 4 primes in the 2021 Tour de PrimesFound 2 mega primes in the 2021 Tour de PrimesFound 3 primes in the 2022 Tour de Primes321 LLR Emerald: Earned 50,000,000 credits (50,515,691)Cullen LLR Emerald: Earned 50,000,000 credits (50,743,293)ESP LLR Emerald: Earned 50,000,000 credits (50,849,415)Generalized Cullen/Woodall LLR Emerald: Earned 50,000,000 credits (50,473,530)PPS LLR Emerald: Earned 50,000,000 credits (78,166,592)PSP LLR Emerald: Earned 50,000,000 credits (51,069,305)SoB LLR Emerald: Earned 50,000,000 credits (51,885,310)SR5 LLR Emerald: Earned 50,000,000 credits (50,409,361)SGS LLR Emerald: Earned 50,000,000 credits (50,445,782)TRP LLR Double Bronze: Earned 100,000,000 credits (100,402,493)Woodall LLR Emerald: Earned 50,000,000 credits (74,008,553)321 Sieve (suspended) Sapphire: Earned 20,000,000 credits (20,380,527)Cullen/Woodall Sieve (suspended) Gold: Earned 500,000 credits (744,531)Generalized Cullen/Woodall Sieve (suspended) Turquoise: Earned 5,000,000 credits (5,007,004)PPS Sieve Double Gold: Earned 500,000,000 credits (636,648,331)TRP Sieve (suspended) Bronze: Earned 10,000 credits (21,181)AP 26/27 Double Silver: Earned 200,000,000 credits (202,222,774)GFN Double Gold: Earned 500,000,000 credits (637,023,067)WW Double Turquoise: Earned 5,000,000,000 credits (5,700,000,000)
Message 153092 - Posted: 6 Jan 2022 | 22:42:53 UTC
Last modified: 6 Jan 2022 | 22:55:42 UTC

You can use MT wherever you want where it is possible to use MT.
MT is determined by cache on your CPU - usually just L3.
You look at FFT of the tasks - times by 8 - this is what is considered as how much cache is needed to run the task fully within cache which should be always much faster.
MT is to manage tasks to run within cache.
MT is for best use of resources or maybe to manage heat.
Or to use as you want.

tngProject donor
Send message
Joined: 29 Aug 10
Posts: 458
ID: 66603
Credit: 43,243,096,027
RAC: 22,593,189
Discovered the World's First base 25 Generalized Cullen prime!!!Discovered the World's First base 73 Generalized Cullen prime!!!Discovered 68 mega primesEliminated 2 conjecture "k"sDiscovered 2 AP26sDiscovered 1 twin primeDiscovered 1 Fermat divisor2017 Tour de Primes highest prime count2017 Tour de Primes most Mountain Stage primes2018 Tour de Primes most Mountain Stage primesFound 4 primes in the 2018 Tour de PrimesFound 1 mega prime in the 2018 Tour de PrimesFound 4 primes in the 2018 Tour de Primes Mountain StageFound 1 mega prime in the 2018 Tour de Primes Mountain StageFound 1 prime in the 2019 Tour de PrimesFound 1 mega prime in the 2019 Tour de Primes2020 Tour de Primes largest primeFound 3 primes in the 2020 Tour de PrimesFound 2 mega primes in the 2020 Tour de Primes2021 Tour de Primes most Mountain Stage primesFound 9 primes in the 2021 Tour de PrimesFound 6 mega primes in the 2021 Tour de PrimesFound 3 primes in the 2021 Tour de Primes Mountain StageFound 1 mega prime  in the 2021 Tour de Primes Mountain Stage2022 Tour de Primes highest prime count2022 Tour de Primes highest prime scoreFound 37 primes in the 2022 Tour de PrimesFound 12 mega primes in the 2022 Tour de Primes321 LLR Double Silver: Earned 200,000,000 credits (222,064,985)Cullen LLR Double Silver: Earned 200,000,000 credits (268,853,479)ESP LLR Double Silver: Earned 200,000,000 credits (205,475,046)Generalized Cullen/Woodall LLR Double Silver: Earned 200,000,000 credits (230,726,473)PPS LLR Double Gold: Earned 500,000,000 credits (842,262,648)PSP LLR Double Silver: Earned 200,000,000 credits (213,474,668)SoB LLR Double Gold: Earned 500,000,000 credits (502,781,170)SR5 LLR Double Silver: Earned 200,000,000 credits (219,646,841)SGS LLR Double Silver: Earned 200,000,000 credits (226,197,828)TRP LLR Double Gold: Earned 500,000,000 credits (773,496,078)Woodall LLR Double Silver: Earned 200,000,000 credits (216,174,567)321 Sieve (suspended) Double Bronze: Earned 100,000,000 credits (134,986,204)Cullen/Woodall Sieve (suspended) Sapphire: Earned 20,000,000 credits (30,879,764)Generalized Cullen/Woodall Sieve (suspended) Double Bronze: Earned 100,000,000 credits (100,428,955)PPS Sieve Double Turquoise: Earned 5,000,000,000 credits (5,158,493,597)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Double Bronze: Earned 100,000,000 credits (101,857,516)TRP Sieve (suspended) Emerald: Earned 50,000,000 credits (50,936,081)AP 26/27 Double Ruby: Earned 2,000,000,000 credits (2,499,123,848)GFN Double Turquoise: Earned 5,000,000,000 credits (8,611,178,030)WW Double Jade: Earned 10,000,000,000 credits (16,390,276,000)PSA Double Turquoise: Earned 5,000,000,000 credits (6,244,536,362)
Message 153093 - Posted: 6 Jan 2022 | 23:29:22 UTC - in response to Message 153091.

The ones were MT is not recommended are simply the smaller ones, where MT is unlikely to be beneficial.

The drawback to using MT on these is that there is some overhead; if the tasks are not large enough to see a benefit, you may actually get reduced throughput using MT. Individual tasks will still run faster (although even this may not be true if you do something extreme, like running SGS with 16 threads).
____________

Profile dannyridel
Volunteer tester
Avatar
Send message
Joined: 3 Feb 19
Posts: 981
ID: 1097922
Credit: 52,224,342
RAC: 155,081
Discovered 1 mega prime321 LLR Amethyst: Earned 1,000,000 credits (1,141,452)Cullen LLR Gold: Earned 500,000 credits (719,717)ESP LLR Gold: Earned 500,000 credits (517,207)Generalized Cullen/Woodall LLR Amethyst: Earned 1,000,000 credits (1,116,617)PPS LLR Ruby: Earned 2,000,000 credits (3,567,975)PSP LLR Gold: Earned 500,000 credits (616,940)SoB LLR Gold: Earned 500,000 credits (533,625)SR5 LLR Gold: Earned 500,000 credits (664,541)SGS LLR Amethyst: Earned 1,000,000 credits (1,004,784)TRP LLR Gold: Earned 500,000 credits (975,469)Woodall LLR Gold: Earned 500,000 credits (628,730)321 Sieve (suspended) Gold: Earned 500,000 credits (506,814)Generalized Cullen/Woodall Sieve (suspended) Bronze: Earned 10,000 credits (30,033)PPS Sieve Turquoise: Earned 5,000,000 credits (5,227,961)AP 26/27 Ruby: Earned 2,000,000 credits (4,580,719)GFN Turquoise: Earned 5,000,000 credits (8,886,823)WW Sapphire: Earned 20,000,000 credits (21,136,000)PSA Silver: Earned 100,000 credits (373,034)
Message 153097 - Posted: 7 Jan 2022 | 2:34:38 UTC

Some others like PPS SV and GFN (that's not GFN21) either don't support MT or have software that's not optimized when using MT.
____________
My lucky number is 6219*2^3374198+1


Post to thread

Message boards : Number crunching : How are multi-threading recommendations determined?

[Return to PrimeGrid main page]
DNS Powered by DNSEXIT.COM
Copyright © 2005 - 2022 Rytis Slatkevičius (contact) and PrimeGrid community. Server load 1.58, 1.41, 1.74
Generated 5 Dec 2022 | 8:00:27 UTC