PrimeGrid Challenges 2019

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Ken g6

Programming Moderator, Elite Member
Moderator
Dec 11, 1999
16,284
3,905
75
Current challenge: Prime Sierpinski Problem (PSP) LLR, December 12-21 (04:19 UTC)

Happy new year! Here's the (tentative) list of this year's PrimeGrid challenges:

Code:
#  Date             Time UTC  Project  Duration  Challenge
-----------------------------------------------------------------------------------------------------------------
1   7-22 January    05:43:00  SoB-LLR  15 days   Conjunction of Venus & Jupiter Challenge
2   5-10 March      18:00:00  GCW-LLR  5 days    Year of the Pig(ging out on our CPU cycles :P) Challenge
3  24-31 May        00:00:00  TRP-LLR  7 days    Hans Ivar Riesel's 90th Birthday Challenge
4  15-20 July       20:17:00  PPS-LLR  5 days    50th Anniversary of the Moon Landing Challenge
5   3-10 August     00:00:00  ESP-LLR  7 days    Lennart Vogel Honorary Challenge
6  21-26 September  11:00:00  AP27     5 days    Oktoberfest Challenge
7  10-15 October    18:00:00  PPS-DIV  5 days    World Maths Day Challenge
8  24-29 October    00:00:00  321-LLR  5 days    50 years First ARPANET Connection Challenge
9   1-11 November   18:04:00  PSP-LLR  10 days   Transit of Mercury Across the Sun Challenge
10 12-22 December   04:19:00  GFN-21+  10 days   Aussie, Aussie, Aussie! Oi! Oi! Oi! Summer Solstice Challenge

What you need:
  • One or more fast x86 processors, preferably with lots of cores. (Even slow ones might do!)
  • Windows (Vista or later 64-bit, or XP or later 32-bit), Linux, or MacOS 10.4+.
  • BOINC, attached to PrimeGrid (http://www.primegrid.com/).
  • Your PrimeGrid Preferences with only the above project(s) selected in the Projects section.
  • Patience! All of these projects run long, slow WUs, at least on your CPU. As a result, no challenge is less than five days long.

What may help LLR (all but two of the challenges):
  • An Intel Sandy Bridge or later ("Core series" other than first-generation) processor with AVX may be 20-70% faster than with the default application. Sadly, that does not include Pentium or Celeron processors, or AMD processors.
  • In most challenges - probably all of these since their WUs are so large - it helps to enable multi-core processing with app_config.xml. Leave hyper-threading on if you do this!
  • Faster RAM might help on many challenges, as long as it's stable.
What may help in other challenges:
  • A GPU helps in two challenges.
  • Juggling in some extra WUs may help in challenges where you run more than one WU on the CPU at a time. (Or, switching to use all cores on one WU at the end may work equally well.)
  • Turning on hyper-threading may help.

What won't help (but won't hurt either):
  • A large amount of RAM.
  • Any Android devices.

What won't help (and will hurt, sort of):
  • Unstable processors. (Invalid work will be deducted! If Prime95 worked recently on your processor, it should be stable.)
  • Work not downloaded anduploaded within the challenge. (It's not counted.) Should you not be able to be in front of one or more computers at that time, there are several options:
    • You can often set BOINC's network connection preferences to wait until a minute or two after challenge time.
    • And for short work units, you can just set the queue level very low (0.01 days). This also makes it more likely that you will be a prime finder rather than a double-checker. But you might want to raise their queue size after the challenge is underway.

Welcome and good luck to all!

P.S. If no one has posted stats lately, try tracking your stats with my user script. With that installed, visit the current challenge's Team stats link for TeAm stats.
 
Last edited:

VirtualLarry

No Lifer
Aug 25, 2001
56,450
10,119
126
Reactions: TennesseeTony

Ken g6

Programming Moderator, Elite Member
Moderator
Dec 11, 1999
16,284
3,905
75
8​
Rechenkraft.net
6 688 826.09​
14 743​
9​
TeAm AnandTech
5 735 255.78​
12 110​
10​
Crunching@EVGA
5 587 842.02​
12 180​
Movin' on up... to the EastSide! (Apologies to some 70s/80s TV show, bonus points if you can tell me what it was called. I forget.)

Edit: 'The Jeffersons'
Wow, I like the inflection on that graph... wonder if we can squeeze in an 8th-place finish? That would be really sweet.
So, the theme this morning is '80s TV shows? How about "Eight is Enough"?

Rank__Credits____Team
5_____11930222___[H]ard|OCP
6_____11694737___AMD Users
7_____9373318____Antarctic Crunchers
8_____7003623____TeAm AnandTech
9_____6987895____Rechenkraft.net
10____5941081____Crunching@EVGA
11____5325262____Storm
 

StefanR5R

Elite Member
Dec 10, 2016
5,691
8,264
136
So I took measures on Sunday to guarantee that I would run only jobs with 256...288K long FFTs for the whole challenge, such that I wouldn't have to switch to different multithreading settings on the go. Turns out that this wasn't needed after all, as the latest tasks sent by the server are still at 288K. (Even 256K tasks are still being sent, generally as 3rd replications of WUs which had one earlier task cancelled.) Nevertheless I don't regret to have prepared myself on Sunday in this way. :-)
 

Ken g6

Programming Moderator, Elite Member
Moderator
Dec 11, 1999
16,284
3,905
75
Preliminary final stats:

Rank___Credits____Username
27_____1868410____xii5ku
36_____1458180____crashtech
47_____1152675____Howdy
68_____829740___10esseeTony
96_____597604_____biodoc
107____517563_____Ken_g6
108____500989_____Orange Kid
139____352876_____SlangNRox
145____332164_____VirtualLarry
190____214410_____zzuupp
222____155652_____emoga
239____139787_____Lane42
368____42072______iwajabitw
382____37178______[H]Skillz
413____23721______Kiska

Rank__Credits____Team
5_____12440981___[H]ard|OCP
6_____12190506___AMD Users
7_____9762950____Antarctic Crunchers
8_____8223028____TeAm AnandTech
9_____7402584____Rechenkraft.net
10____6236226____Crunching@EVGA
11____5563591____Storm

Not bad for being below 15th the first three days!
 

StefanR5R

Elite Member
Dec 10, 2016
5,691
8,264
136
Here is a schedule, based on UTC.
Code:
      October  Th·24  Fr·25  Sa·26  Su·27  Mo·28
Formula Boinc   ____  ▄▄▄▄▄  ▄▄▄▄▄  ▄▄▄▄▄  ▄
    PrimeGrid  ▄▄▄▄▄  ▄▄▄▄▄  ▄▄▄▄▄  ▄▄▄▄▄  ▄▄▄▄▄


------------

Edit,
I went fishing for an LLR-321 task which I could use for performance tuning.
At first, I got a 3rd replica, called llr321_327835846_3, with this input file:
600000000000000:P:1:2:257
3 15085929
sllr64.3.8.23 says this in slots/?/stderr.txt on a Haswell processor:
Using all-complex FMA3 FFT length 800K, Pass1=640, Pass2=1280, clm=2, 7 threads, a = 5

Since I want my test specimen as close to the "leading edge" as possible, I fetched another task and got a 2nd replica this time, called lr321_327835971_2:
600000000000000:M:0:2:258
3 15086740
The tail end of the corresponding stderr.txt:
Using FMA3 FFT length 800K, Pass1=320, Pass2=2560, clm=2, 7 threads
(800K FFT length means 6.25 MB FFT data size.)

I will proceed testing with the latter work unit. But does anybody know what the difference between "Using all-complex FMA3…" and "Using FMA3…" is?

Edit 2,
my prior tests were with unknown FFT length on Broadwell-EP in 09/2017, and with 768K FFT length (6.0 MB data size) on Haswell in 03.2018.
 
Last edited:

Ken g6

Programming Moderator, Elite Member
Moderator
Dec 11, 1999
16,284
3,905
75
@StefanR5R, I think one of those tests is 3*2^n+1, while the other is 3*2^n-1. They use different tests, but the timing should be substantially similar, I think.
 

StefanR5R

Elite Member
Dec 10, 2016
5,691
8,264
136
@StefanR5R, I think one of those tests is 3*2^n+1, while the other is 3*2^n-1. They use different tests, but the timing should be substantially similar, I think.
Thanks.
The former ... tests 3*2^15085929+1 and gives 5,668.37 credit.
The latter ...... tests 3*2^15086740-1 and gives 5,689.43 credit.

The former used more run time and CPU time as the latter, but I ran them both with uncontrolled concurrent load. I am testing them both on an otherwise idle system now. On a 4-core Haswell, run time is at the order of 5 hours, hence a bunch of 10% tests is relatively quickly to perform. I'll also run one 100% test on the testing PC for calibration. (Edit: An i7-7700K is completing 10% of a job in under 20 minutes.)
 
Last edited:

crashtech

Lifer
Jan 4, 2013
10,554
2,138
146
If we had some kind of captain, we could allocate our resources between PrimeGrid and the Formula BOINC Sprint which should be known in about 5 hours, I think.
 

StefanR5R

Elite Member
Dec 10, 2016
5,691
8,264
136
I went fishing for an LLR-321 task which I could use for performance tuning. [...]
The tail end of the corresponding stderr.txt:
Using FMA3 FFT length 800K, Pass1=320, Pass2=2560, clm=2, 7 threads
(800K FFT length means 6.25 MB FFT data size.)
Of the tasks which I fetched at the start of challenge, only a few still had 800K FFT length.
Most are at 864K now ( = 6.75 MB FFT data size).

You can check with grep FFT /var/lib/boinc*/slots/*/stderr.txt
 

crashtech

Lifer
Jan 4, 2013
10,554
2,138
146
Of the tasks which I fetched at the start of challenge, only a few still had 800K FFT length.
Most are at 864K now ( = 6.75 MB FFT data size).

You can check with grep FFT /var/lib/boinc*/slots/*/stderr.txt
Oh, might that change the cache math for the CPUs in play?
My retest of the 2x 2680v2 system did not result in any significant differences, although the 6 task / 6 thread result went down a bit, which was not expected.
 

StefanR5R

Elite Member
Dec 10, 2016
5,691
8,264
136
Oh, might that change the cache math for the CPUs in play?
Not likely. The optimum llr321 config is most often one which doesn't use the L3$ fully but uses all cores (or rather: all, or almost all, hardware threads). With this size increase by 0.5 MB per task, most CPUs will still have enough cache with the same config.
My retest of the 2x 2680v2 system did not result in any significant differences, although the 6 task / 6 thread result went down a bit, which was not expected.
This latter phenomenon is alright. I have seen myself that quick tests which stop at a low progress percentage consistently give conservative results, compared with longer or even complete tests (in llr321).
 

Ken g6

Programming Moderator, Elite Member
Moderator
Dec 11, 1999
16,284
3,905
75
Day 1 stats:

Rank___Credits____Username
24_____348848_____crashtech
29_____252054_____biodoc
37_____219079_____Howdy
61_____144680_____Ken_g6
71_____119502_____Orange Kid
75_____112928_____emoga
108____68020______xii5ku
117____56938______SlangNRox
143____43840___10esseeTony
175____25214______zzuupp

Rank__Credits____Team
5_____1970354____[H]ard|OCP
6_____1818061____AMD Users
7_____1616028____Crunching@EVGA
8_____1391107____TeAm AnandTech
9_____1023583____BOINC@MIXI
10____865587_____Antarctic Crunchers
11____785857_____Storm

You could say that, drop by drop, things are going swimmingly.
 
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