On Wednesday 19 December 2007 22:18, Jeff Woods wrote: > > After I wrote the above, a test indicated that if I raise RAM > allocations to 384 MB around the clock, the estimated time to complete > Stage 2 drops from 5.5 days to 1.5 days, so I've answered my own > question for my own purposes... but given this, aren't the docs outdated > when it comes to RAM requirements for P-1 factoring and/or the defaults > for RAM allocation in the software such that most people won't be making > effective use of their P-1 factoring time unless they both have the RAM > to spare (as I do), and are educated enough to change the defaults?
I think there may be an issue with multi(core) processor systems here. The relative timings were AFAIK derived on uniprocessor systems. If you are running several instances of P-1 stage 2 in parallel you may well be cache thrashing to an unacceptable degree. However this situation will probably not persist as after the system has been running for a while the multiple instances will "desynchronise" so that it will be unusual for more than one instance to be running P-1 stage 2. Setting memory to 8MB (which used to be the default) disables P-1 stage 2, but allows stage 1 (with a larger limit to compensate); this may be the short term answer to this "problem". Better (in the long term) if an instance wants to start P-1 stage 2 but finds that another instance is already running stage 2, the subsequent instance could start LL testing immediately, then go back and run P-1 stage 2 when the other instance has finished. Regards Brian Beesley _______________________________________________ Prime mailing list [email protected] http://hogranch.com/mailman/listinfo/prime
