Question about rapid RAC dropoff
27 Jan 2013 21:57:47 UTC
Topic 196773
(moderation:
I'm still a relative newbie to E@H (since Sept of 2012), so I'm not familiar with expected statistical variation in RAC numbers.
Combined, my two computers used for E@H produce a RAC of about 12,300 over the long term. Recently however (for the past 4-weeks) I've noticed a radical drop-off in my RAC from a high of 13,700 down to 11,000 and the rate of drop-off is actually increasing. (I do not utilize GPU devices, so I only process Gravitational Wave searches.)
Nothing else seems wrong. Each core of the CPUs runs at 100%, 24/7, and the CPU coolers are very good at keeping the core temperatures under 48C.
Is this RAC variance within normal parameters, or should I look for other problems?
Thanks for your help!
Question about rapid RAC dropoff
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Looks like normal variation. You don't have any error/invalid tasks; and your runtime/task hasn't varied appreciably over the last few weeks.
Because E@H generates large numbers of WUs that share the same set of data files you tend to be partnered with the same people for a set of tasks for a few weeks at a time; if you end up with a bunch of people who have long queues or who are timing out on tasks that can make a temporary dent in your RAC (to be followed up by a temporary boost when the tasks eventually come in).
Also, nothing jumps out in
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Also, nothing jumps out in boincstat's graphs. Their 2 month RAC chart shows a drop in late November/early December, followed by a spike later in the month that was probably caused by something similar to what I described in my last post.
http://boincstats.com/en/stats/-1/user/detail/2506795/charts
Hi, that drop might be
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Hi,
that drop might be related to the Gamma-ray pulsar search #2 v0.01 credit change. Til like 3 weeks ago you got 337 credits for a WU, since then it got adjusted to 70 credits.
As your RAC is an average of the last 30 days (afaik) the changes are still hitting.
You might have noticed the overall combined RAC (or whatever its called) dropping below 1 TFLOPS during the last few days. That is related to the Gamma-ray pulsar search #2 v0.01 credit change as well i guess.
Just my guesses, hope i could help
DaSumpf
Thank you. That's the answer
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Thank you. That's the answer I was hoping to hear! When I first began crunching the numbers I was delighted to see how my RAC continued to climb, week after week, and I was astonished to see that it topped 13,700 for a little while. But the quick decline to 11,000 was unsettling, not knowing for sure what was causing it. Again, thanks for taking the time to answer. I appreciate it. -- Andy
RE: Combined, my two
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There's nothing particularly abnormal with the sort of swings you mention. After all 12,300 is pretty much the average of 13,700 and 11,000 :-). Swings of that magnitude are not unusual.
There's a very good reason for that. Apart from what Dan mentions, which is perfectly true and the general cause of RAC variations, there is a special situation at the moment. The previous S6LV run is now in 'cleanup' phase which means that all 'primary' tasks have been sent and that only 'secondary' tasks (resend tasks to replace failed primaries) remain. By definition, you are very likely to get 'instant gratification' from resends you return because there will likely be a waiting primary task against which immediate validation can occur. As the resends decline in numbers, you are likely to get mainly primary tasks from the new run.
I only looked at your i5-2500 host but, until a couple of days ago (around Jan 25th) it was cleaning up a bunch of resends (task name has _2 or higher extension) and receiving instant validation. Since then, it has switched to the new 'Extended' run and it has received close to 200 of these tasks. Of the ones that have been returned, the vast majority (more than 90% - check for yourself) are 'pending' and this factor alone would account for a dropping RAC right now. Essentially, no new credit from tasks recently completed has come in.
At the start of a new run, there is always a bit of a lull in partners and returned tasks so this high level of pendings is not unusual. The bright side is that validations will eventually 'catch up' and you should see an upward trend when that happens.
As Dan says, there is noting obviously wrong. While I've been composing this message, another reply has come in suggesting the 337 -> 70 credit change for FGRP2 tasks. That was my first thought as well but once I looked at your i5-2500 host and saw there were zero FGRP2 tasks in the full list, the credit change cannot be affecting you.
You mentioned quite pointedly that you weren't using GPUs. There is a huge increase in efficiency as measured by any metric you might choose, if you were to. Depending on what sort of case and PSU you have, you could add a modern low power GPU costing around $100 and end up with a RAC around 20-25K, ie around 4-5 times your current score. I just thought I'd mention that as you seem interested in how your RAC is going :-).
Cheers,
Gary.
Thanks, Gary. I was able to
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Thanks, Gary. I was able to learn enough from your detailed reply that I can probably do my own analysis for future concerns. I had never kept track of the highly variable number of pending results before now. My biggest concern was whether my relatively new computer-builds were actually performing as well as they could be, even though limited to CPU computations.
But, now you've convinced me to add GPUs to the machines. :)
There is, however, a bit of a glitch: I am currently trying to figure out how to physically add them to the computers. Apparently I picked a perfectly horrible motherboard model for use with big, fat GPUs! The rectangular cowlings on the lower-priced GPUs would render two (of the four) available SATA ports inaccessible. (The motherboards only have a single PCIE 3 x16 slot available, with the SATA ports located directly underneath the cowling of any installed GPU.) I am trying to find sizing specs for various GPU models that might circumvent this problem with non-rectangular cowlings (such as the ASUS GTX650-E-1GD5). There are some other workarounds and reconfigurations that I could also try. The PSUs aren't a concern, nor are the case sizes. I'll figure it out, eventually.
RE: There is, however, a
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Ok not knowing which board you have "didn't look it up" here is 2 ideas I can think of "off the top of my head"
1. Your ports are straight up which means plugging the sata cable in means they come out away from your board and to the side of your case. If this is the case you should be able to use one of the cables that has the 90 degree angle on it and the card should fit with it.
2. If you can't make the cable work you may be able to get a pci card with sata ports on it making the ports not in the way of the GPU card. Also there is a usb hub cable which makes for sata adapter.
Now as far as the mother boards "alot of them" don't have the space that's needed to do things but there is always a work around of doing it you just have to find it. Best of luck.
Edit: If your ports are already at an angle the GPU should not be in the way. Where my card goes it makes it really hard to get to the bios battery and the sata ports and it also blocks another pci-e 1x slot. Look down next to the battery there is 4 sata ports at an angle and 2 thats straight up. If your baord is about the same you should not have a sata cable problem. If it's like the 2 ports up then the angle cable should help with it. Hope this helps. "This is my board by the way"
PC setup MSI-970A-G46 AMD FX-8350 8 core OC'd 4.45GHz 16GB ram PC3-10700 Geforce GTX 650Ti Windows 7 x64 Einstein@Home
Yep, the 90-degree SATA
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Yep, the 90-degree SATA connector solution is exactly what I'll be using. In examining my motherboard, (MSI H61M-P31 (G3)), I noted that the "straight-up" SATA#1 port will require a "left hand" 90-degree connector and I quickly found one at Newegg (Item=N82E16812123282). Since I only need three SATA connections, I'll just use ports #3 and #4 for my backup HDD and the optical drive. I ordered a GPU earlier today (ASUS GTX650-E-1GD5). If all works well, I'll duplicate the order for my other, nearly identical computer next week.
I'm also sure I'll be back here asking about proper E@H GPU setup preference choices, once the stuff arrives. ;-)
Thanks for your suggestion!