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Old 2021-01-20, 07:46   #76
joniano
 
Jan 2021

12 Posts
Default Possible Symptoms of a Bug on ARM64 Build - Running too fast

Hello Folks - I recently got Mlucas running on a Raspberry Pi 4, 8GB of RAM, running Ubuntu and I am doing PRP checks on large primes.

I'm assuming either Mlucas is extremely fast and consistent or I'm running into some sort of a bug.

If you look at a few lines of the ".stat" file for one of my recent primes, you'll see that every few seconds I blast through 10,000 iterations at exactly the same ms/iter speed and it seems to take under a day to fully PRP test a new number.

Code:
[2021-01-19 21:42:45] M110899639 Iter# = 110780000 [99.89% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:42:48] M110899639 Iter# = 110790000 [99.90% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:42:50] M110899639 Iter# = 110800000 [99.91% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:42:52] M110899639 Iter# = 110810000 [99.92% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:42:55] M110899639 Iter# = 110820000 [99.93% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:42:57] M110899639 Iter# = 110830000 [99.94% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:42:59] M110899639 Iter# = 110840000 [99.95% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:43:01] M110899639 Iter# = 110850000 [99.96% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:43:04] M110899639 Iter# = 110860000 [99.96% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:43:06] M110899639 Iter# = 110870000 [99.97% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:43:08] M110899639 Iter# = 110880000 [99.98% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:43:10] M110899639 Iter# = 110890000 [99.99% complete] clocks = 00:15:20.953 [ 92.0954 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
[2021-01-19 21:43:13] M110899639 Iter# = 110899639 [100.00% complete] clocks = 00:15:20.953 [ 95.5445 msec/iter] Res64: 461E323B49699D73. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Residue shift count = 13555775.
M110899639 is not prime. Res64: 243C3E785D7D8345. Program: E19.0. Final residue shift count = 13555775
M110899639 mod 2^35 - 1 =          20387533375
M110899639 mod 2^36 - 1 =          12983321457
Does this look suspicious to anyone else?

I also run Prime95 on a seemingly much more powerful Core i7-7700 and that is taking about 14 days to PRP-test a single number, which is what is making me question this.

I'm glad to provide more detail if it would help troubleshoot.
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