Date: Fri, 6 Sep 2013 05:47:06 +0100 From: Rafael Waldo Delgado Doblas <lord.rafa@...il.com> To: john-dev@...ts.openwall.com Subject: Re: Parallella: Litecoin mining Hello Alexander, 2013/9/5 Solar Designer <solar@...nwall.com> > This is a good point. However, please note that with mining many things > are probabilistic. The time it'd take for us to find a share will vary. > Although it might take e.g. 2 hours on average at the awful speed we > currently have, it might also take e.g. 1 second if we're really lucky. > My understanding is that when we're forced to start mining for a new > block, we lose only a very small portion of work (and actually some > pools accept "stale shares", I think). On one hand, yes, our "2-hour > average" (or whatever) period starts anew, but on the other it does not > matter for our chances to find a share on any given second. > > Here's an analogy: computer hardware MTBF: > http://en.wikipedia.org/wiki/Mean_time_between_failures > For example, a hard disk drive might have an MTBF of 1000000 hours. > If we replace HDDs every hour, will we never encounter a HDD failure? > Per the MTBF model, no - we'll run into a HDD failure anyway, as long as > the density function is not a constant zero for the 0 to 1 hour period. > Often it is assumed to be such that we'd run into failures every > 1000000 hours on average anyway. And it is actually (almost) such in > cryptocurrency mining, I think. > About this I need to launch a test for long time and check what happen because if I force to epiphany cores to return 0, everything looks normal (of course I get a lot of Rejected). Today I have implemented a new TMTO. Now the first "NO_TMTO_GROUPS" elements from V that the (position%TMTO_RATIO) is equal to (TMTO_RATIO - 1) will be stored, in addition of any element that (position%TMTO_RATIO) is equal to 0. With this TMTO implementation we can handle tmto ratios between 5 and 4. I have chosen (TMTO_RATIO - 1) because this elements should be harder to recompute than (TMTO_RATIO - 2),(TMTO_RATIO - 3)...(2),(1). The maximum value for NO_TMTO_GROUPS at the moment is 11. Regards, Rafael. Content of type "text/html" skipped
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.