Good discussion. A couple of questions/comments:
1. re: kasson's announcement. I took that as saying the one server listed would be down. For the -bigadv WUs that I have processed, there are three or more different bigadv servers.
a. 130.237.232.141 for p6900
b. 130.237.232.237 for p6901
c. 171.67.108.22 for p2684/2685
d ??? for others
Are all of these servers to be out of service, or just 130.237.232.141, as noted in the announcement below??? That will say whether all of the bigadv folders need to change their flag NOW to get regular SMP WUs next, or whether the mix will change. e.g., give all of us 2684s to chew on for the next few weeks, if there are that many WUs queued up.
Re: Updates thread
by kasson » Tue May 31, 2011 9:10 am
bigadv server 130.237.232.141 is going into accept-only mode for a few days. We're getting ready to upgrade the server software there, and we can't have any outstanding jobs when we do that.
2. re: Bruce's post.
DISCLAIMER. I'm folding bigadvs on my new Sandy bridge i7 2600k system. This system folds a p6900/6901 bigadv, with only a moderate overclock, in 2.2 days vs the Stanford deadline of 4 days. The p2685s take a few hours longer, and the p2684s a lot longer, but still well within the established deadlines. I'm more than willing to abide by whatever decision is made to best further the science, and hope that objective value functions are used to make these decisions.
My view of FAH is that there is a finite but large set of things to be studied - driven by the capability and capacity of the researchers front end preparation and back end processing of results/issuing next-gen WUs. There may be some problems that become "solved", and we should celebrate just that (HINT: it would be very good for PL to let the donors know when one series of projects has come to an end - that the set of trajectories has taken a particular problem set to a logical conclusion.)
I think there are definitely things to be said for the options. I myself think that the PROJECT would be better served by implementing something like #3. I know there was a recent thread asking about the assignment server being able to make decisions based on the Performance Fraction (to use a v6 term) - to preference assignment to those best able to do it.
But, it is an interesting queuing problem. the PROJECT wants the best and fastest completion of its study trajectories.
(Disclaimer. I'm just pulling all of these numbers out of the air for talking purposes. I have no idea how many there really are. The conclusions will differ depending on the actual pouplations)
If there are 10,000 WUs, should they all be reserved for the, say, 100 users who can complete one of the 2684s in less than a day, thus taking ~ 100 wall-clock days to complete the 10,000 WUs, or should the, say, 500 users who can process one of the 2684s in 2.5 days (which still beats the deadline by 1.5 days) be also folding? There is a serialization of the trajectories to consider too - the results of one generation needed to seed the subsequent generations.
a. 100 fastest only complete 10,000 WUs in 100 days
b. 100 fastest plus 500 i7s complete 10,000 WUs in 33 days? (I apologize for what may be fuzzy math.)
What exactly, then, is Stanford's value proposition for the completion?
I threw out somewhat random numbers - but those who know what the real numbers can use an analysis something like this to help determine what the value function is.
Along the way, if we do tweak with the QRB and tweak with the deadlines (say 3 days vs 4 days), we want to be able to up front weed out the incapable folders. The idea of preferencing, or even filtering, the users who can complete with the best performance fraction is good - but we don't want to cut the pool of folders so low that the net result is delaying the science. That's why Stanford needs to articulate their REAL capacity to generate new projects, and process the incremental returns.
It's not rocket science to come up with preferencing formulas. That's a good classroom assignment for undergrads. But the system does need to articulate its value function. i.e., what's the value of finishing an arc of 10,000 bigadv WUs in 33 days vs 100 days for the assumptions I've made? What's the value function for the REAL population of folders we are seeing? The "folder in the street" like me see none of those stats, nor do I think I really want to. But, someone knows them.
Re: What 's up with the bigadv server(s) ?
by bruce » Tue May 31, 2011 4:54 pm
...
1) What do you think about randomly assigning standard SMP projects to people who have asked for -bigadv when there's a shortage of the preferred projects?
2) What do you think about dynamically reducing the bigadv bonus to reduce demand and make standard SMP more equitable?
3) What do you think about dynamically increasing the requirements for -bigadv (Give increasing priority to machines with higher numbers of core or larger RAM or machines that return WUs by increasingly wide margins ahead of deadlines)