Discussion related to cado-nfs

[Paul Zimmermann <Paul.Zimmermann@inria.fr>]

       Hi Jason,

> [Re-sending this message because it's a good idea to check the size of
> logfile before attaching to email.  Sorry if this is a near-duplicate,
> Eric.]
> 
> I've uploaded a copy of my logfile for that factorization to
> https://storage.googleapis.com/number-field-sieve/run/77377_135.log .
> 
> Total runtime was about 3 months, with numerous interruptions during
> sieving, krylov and one failure during sqrt.
> 
> Some interruptions were because I was experimenting with thread counts,
> others because of power failures, and the sqrt interruption because I
> had to drop threads from 8 to 4 to not run out of memory.
> 
> In particular one interruption during krylov was checking that
> utlization and s/iter did not improve by running 64 threads instead of
> 32.  I also remmeber that total CPU utilization reported by htop during
> krylov was fairly low, around 30 to 40%.
> 
> Whether this might be of particular help in understanding my CPU and
> real time reports, I'm not sure.  I do still have all the files
> generated by the factorization, so if parameter snapshot files and so
> forth are useful, I can also make those available.

thank you. My guess is that in the final report:

   Total cpu/elapsed time for entire factorization: 2.37178e+08/2.53203e+06

the elapsed time of 2.53203e+06 seconds (i.e., about one month) takes
into account only part of the whole factorization, while the cpu time of
2.37178e+08 seconds (i.e., about 7.5 core-years) might represent the total
time spent.

In short, timings reports for interrupted factorizations should be
interpreted with care, and it is not our top priority to fix that!

Best regards,
Paul