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Old 2020-09-02, 20:46   #31
VBCurtis
 
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"Curtis"
Feb 2005
Riverside, CA

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I picked out a current SNFS job (from Chris2be8: https://mersenneforum.org/showpost.p...postcount=2464) to test memory use. This job has lim's of 134M and 31LP, going to the "d" 14e queue despite the notes estimating difficulty as GNFS-182 equivalent. Suggested sieve range is 20-200M.

At Q=180M, 14e memory use is 382MB. A 5k Q-range took 29 minutes to run on my 2.5ghz Haswell-era desktop, and found 5723 relations (yield 1.14); sec/rel was 0.296.

On the same input file and same Q 15e memory use is 426MB, so SNFS jobs (on the -r side) do not use more memory than GNFS at the same lim choice. A Q-range of 2500 found 5725 rels in 27 minutes, 0.278 sec/rel.

I tried 16e: Still 427MB memory use. sec/rel was around 0.355 when I aborted after 5 minutes.

It looks like the "d" queue has 1 WU = 15,000 Q-range. This seems a bit high; while this SNFS test-job is quite a bit tougher than will be on the future "d" queue, 90 minutes for 1WU is well outside Carlos' guidance. I hope Carlos can use this timing data to figure out what combo of WU size and points-given will make the BOINCers happy while not shifting attention away from Greg's big queue.
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