2019-12-05, 21:58 | #1 |
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
19·277 Posts |
Factor5
This is a reference thread about Factor5. Post comments in the reference discussion thread. Comments posted here may be moved or removed without recourse or notice.
Factor5 is a cpu-based multithreaded Mersenne trial factoring program that can exceed the 2^{32} exponent limit of Mfaktc and mfakto. The only time Factor5 should be used is for TF that can't be done by gpu programs mfaktc or mfakto or mmff, and Mfactor is not available, or the work to be done exceeds even Mfactor's ample limits. This is because of substantial speed differences. The cpu is better used for PRP, or P-1 factoring. Factor5 is several times slower than Mfactor on the same work and hardware; see the next post. None of that should be mistaken for criticizing any software or its author. Just know the tools capabilities and limitations, and use the right one for the job. See https://www.rieselprime.de/ziki/Factor5 and https://download.mersenne.ca/factor5 It saves status in very readable text in status.txt, a nice feature. The name is apparently fixed, and it checks for its existence on startup, so starting a different assignment requires removing or renaming the status file. Continue with one of these with factor5 --resume. If an incorrect parameter is entered, it prints help: Code:
Usage: factor5 exponent bit_start bit_stop num_threads factor5 --resume factor5 --version num_threads must be 1, 2, 4, 8, 16 Thread table of contents:
https://www.mersenneforum.org/showthread.php?t=22463 https://www.mersenneforum.org/showthread.php?t=14515 https://www.mersenneforum.org/showthread.php?t=7283 https://www.mersenneforum.org/showthread.php?t=9744 Factor5 is not recommended for new work which can be done by any other software, because of speed differences. Use mfaktx or mmff when possible, otherwise use Ernst Mayer's mfactor, which is faster and has more options and capability. Top of reference tree: https://www.mersenneforum.org/showpo...22&postcount=1 Last fiddled with by kriesel on 2020-12-23 at 20:36 |
2019-12-05, 22:00 | #2 |
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
19·277 Posts |
Benchmark and cost
On a dual E5-2697-V2 Xeon system, I made a brief test run of 0.2% of
Code:
Factor5 39845887 73 74 16 Task Manager shows it using 38% of available cpu, with prime95 temporarily stopped. HWMonitor shows it using 80w on one cpu package, 100W on the other. Electrical cost at $0.12/kwhr: 145 hours x 180 W * $0.12/(1000 watt hours) = $3.132. For comparison, an RX550 running mfakto on Factor=39845887,73,74 indicates 8.55 hours. The RX550 indicates using 30 watts. Electrical cost at $0.12/kwhr: 8.55 hours x 30 watts * $0.12/(1000 watt hours) = $0.03078. Time ratio: 145/8.55 =~ 16.96 Electrical cost ratio: 3.132/.03078 =~ 101.8 Clearly it is not competitive with gpu factoring on even a low power old gpu, for exponents in the gpu supported range. But it could be useful for exponents above 2^32, beyond the current capability of gpu trial factoring. A quick test with 8 threads instead gave an estimated run time of 278. hours. A head to head comparison, Factor5 to Mfactor follows for trial factoring MM31 from 67 to 68 bits, while prime95 runs full tilt. Prime95 iteration times are seen to increase by ~15% during the Factor5 16-thread run. Factor5 uses 16 hyperthreads, 36% cpu indicated in Task Manager for the 359 second indicated duration. Code:
factor5 2147483647 67 68 16 Factor5 v. 5.01 - December 27th, 2007 - AMD64/Win64 compile - GMP 4.2.1_MPIR_1.0.0 Current date Fri Aug 28 13:23:38 2020 Factoring M2147483647 from 2^67 to 2^68 0.000% completed. Factoring M2147483647 from 2^67 to 2^68 0.000% completed. Factoring M2147483647 from 2^67 to 2^68 10.317% completed. Factoring M2147483647 from 2^67 to 2^68 20.920% completed. Factoring M2147483647 from 2^67 to 2^68 31.285% completed. Factoring M2147483647 from 2^67 to 2^68 41.412% completed. Factoring M2147483647 from 2^67 to 2^68 51.919% completed. Factoring M2147483647 from 2^67 to 2^68 62.331% completed. M2147483647 has a factor: 242557615644693265201 - Program: L5.0x Factoring M2147483647 from 2^67 to 2^68 72.696% completed. Factoring M2147483647 from 2^67 to 2^68 82.823% completed. Factoring M2147483647 from 2^67 to 2^68 93.331% completed. Factoring M2147483647 from 2^67 to 2^68 91.999% completed. 1 factor found Performed 1179126821 powmod operations since last restart. Used 970704 primes, max. prime = 14999981 Current date Fri Aug 28 13:29:37 2020 Code:
time ./Mfactor -m 2147483647 -bmin 67 -bmax 68 INFO: testing qfloat routines... CPU Family = x86_64, OS = Linux, 64-bit Version, compiled with Gnu C [or other compatible], Version 7.5.0. INFO: CPU supports SSE2 instruction set, but using scalar floating-point build. INFO: Using inline-macro form of MUL_LOHI64. INFO: MLUCAS_PATH is set to "" INFO: using 64-bit-significand form of floating-double rounding constant for scalar-mode DNINT emulation. Setting DAT_BITS = 10, PAD_BITS = 2 INFO: testing IMUL routines... Mfactor build flags: TRYQ = 4 NUM_SIEVING_PRIME = 100000 MULH64_FAST = true FACTOR_STANDALONE = true NOBRANCH = true USE_128x96 = true Mfactor self-tests: Apr2015 mi64_div quicktest passes. mi64_div quicktest passes. Base-2 PRP test of M127 passed: Time = 00:00:00.000 Base-2 PRP test of M607 passed: Time = 00:00:00.000 Base-3 PRP test of M607 passed: Time = 00:00:00.000 Base-2 PRP test of M4423 passed: Time = 00:00:00.093 Base-3 PRP test of M4423 passed: Time = 00:00:00.343 Testing 64-bit Fermat factors... Testing 128-bit Fermat factors... Testing 192-bit Fermat factors... Testing 256-bit Fermat factors... Testing > 256-bit Fermat factors... Testing 63-bit factors... Testing 64-bit factors... Testing 65-bit factors... Testing 96-bit factors... Factoring self-tests completed successfully. INFO: No factoring savefile t2147483647 found ... starting from scratch. Allocated 255255 words in master template, 4255 in per-pass bit_map [16 x that in bit_atlas] Generating difference table of first 100000 small primes Using first 100000 odd primes; max gap = 114 max sieving prime = 1299721 Searching in the interval k=[34355280960, 68726898240], i.e. q=[1.475548e+20, 2.951798e+20] Each of 16 (p mod 60) passes will consist of 2104 intervals of length 272272 2949120 ones bits of 16336320 in master sieve template. TRYQ = 4, max sieving prime = 1299721 Time to set up sieve = 00:00:00.062 pass = 0................ pass = 1................ pass = 2................ pass = 3................ pass = 4................ pass = 5................ pass = 6................ pass = 7................ pass = 8................ pass = 9................ pass = 10................ pass = 11................ pass = 12................ pass = 13................ pass = 14................ pass = 15........... Factor with k = 56474845800. This factor is a probable prime. ..... M(2147483647) has 1 factors in range k = [34355280960, 68726898240], passes 0-15 Performed 1369664700 trial divides Clocks = 00:12:57.140 real 12m58.204s user 12m56.734s sys 0m1.109s This ratio is large compared to the likely effects of running Factor5 on Win10 directly while Mfactor was run on WSL2 atop Win10, and with the efficiency of a single thread. There was not a noticeable impact of Mfactor's one thread on prime95 iteration timings. I have seen impacts of running 16 separate Mfactor processes directly on Win10 via a batch script to do the 16 passes in parallel, similar to the effect of Factor5's 16 threads on prime95 iteration timing. Top of reference tree: https://www.mersenneforum.org/showpo...22&postcount=1 Last fiddled with by kriesel on 2020-08-28 at 18:53 |
2019-12-05, 22:02 | #3 |
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
5263_{10} Posts |
Status file format
The Factor5 save file format seems straightforward.
Here's a snapshot. Code:
39845887 73 74 118515782641998 118612379302158 237031565283998 0 0 16 0 Code:
39845887 73 74 118515782641998 118673885546958 237031565283998 0 0 16 0 Code:
exponent starting bits ending bits starting k (in F=2kp+1) current k ending k (unknown or reserved) (unknown or reserved) cores count (unknown or reserved) Top of reference tree: https://www.mersenneforum.org/showpo...22&postcount=1 Last fiddled with by kriesel on 2019-12-05 at 22:08 |
2019-12-06, 00:44 | #4 |
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
5263_{10} Posts |
Results file
Here is some sample results.txt output. It prints a header line when starting, and if Ctrl-C halts the run, that's all there may be from that run.
Code:
Trial-factoring M39845887 in [2^73, 2^74-1] Trial-factoring M220600496383 in [2^1, 2^70-1] M220600496383 has a factor: 40590491334473 - Program: L5.0x M220600496383 has 1 factors in [2^1, 2^70-1]. Trial-factoring M1049179854847 in [2^1, 2^70-1] M1049179854847 has 0 factors in [2^1, 2^70-1]. Trial-factoring M1049179854847 in [2^1, 2^76-1] M1049179854847 has a factor: 22427111252690237692351 - Program: L5.0x M1049179854847 has 1 factors in [2^1, 2^76-1]. Top of reference tree: https://www.mersenneforum.org/showpo...22&postcount=1 Last fiddled with by kriesel on 2020-08-05 at 20:19 |
2019-12-06, 00:46 | #5 |
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
19×277 Posts |
Console output
Here's a sample run's console output
Code:
Factor5 v. 5.01 - December 27th, 2007 - AMD64/Win64 compile - GMP 4.2.1_MPIR_1.0.0 Current date Thu Dec 05 18:33:36 2019 Factoring M1049179854847 from 2^1 to 2^76 0.000% completed. Factoring M1049179854847 from 2^1 to 2^76 9.754% completed. Factoring M1049179854847 from 2^1 to 2^76 22.866% completed. M1049179854847 has a factor: 22427111252690237692351 - Program: L5.0x Factoring M1049179854847 from 2^1 to 2^76 39.834% completed. Factoring M1049179854847 from 2^1 to 2^76 61.247% completed. Factoring M1049179854847 from 2^1 to 2^76 78.261% completed. Factoring M1049179854847 from 2^1 to 2^76 95.319% completed. Factoring M1049179854847 from 2^1 to 2^76 97.179% completed. 1 factor found Performed 1226096055 powmod operations since last restart. Used 970704 primes, max. prime = 14999981 Current date Thu Dec 05 18:37:16 2019 Top of reference tree: https://www.mersenneforum.org/showpo...22&postcount=1 Last fiddled with by kriesel on 2020-08-05 at 20:19 |
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