Posts by Mr. Kevvy


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1) Message boards : Number crunching : Decided to Bail Out on SETI for a Short While (Message 1790131)
Posted 5 hours ago by Profile Mr. KevvyProject donor
The symptom is abandoning work because of the of the flawed credit system.


As noted too often (including in point #5 below) the people who are doing this inevitably have NVidia cards, which are processing the GUPPI VLAR work slowly due to a design flaw in the memory architecture. Unfortunately, the credit system won't fix that. The only way of doing that would be to have a special multiplier to arbitrarily grant 2.5x the credit for a GUPPI VLAR work unit if it's done on an NVidia card. If that is done, then why shouldn't every other sub-optimally slow platform get its multiplier?
2) Message boards : Number crunching : Decided to Bail Out on SETI for a Short While (Message 1790125)
Posted 5 hours ago by Profile Mr. KevvyProject donor
In case it was missed in the decreasing credit thread:

I was able to contact Dr. Eric Korpela. He indicated that a solution to allow GUPPI VLAR GPU work units to be refused in the Project Prefs. is being worked on. Please pass it along...

Hope this alleviates any of the misgivings that the project admins. aren't aware of this issue or don't care about it.


They know. I'm in the same boat... I just spent thousands to upgrade the farm to all Maxwells plus a new four-card cruncher and this happens. I try to look at the bright side. Here's the bright side:

1) The work we're doing is far more likely to find something, being targeted at known nearby planetary systems with planets as similar to ours as possible.

2) We've gone from a work shortage to too much work; there's always enough now.

3) Because this project is being scrutinized as part of Breakthrough Listen, this work is going to be used, analyzed and searched. It is not going to sit in a database collecting digital dust. I can't tell you how I know this, but I do. This work is worthwhile.

4) My GPUs don't run dry of work on short outages (ie Tuesdays) because the VLAR work units take longer.

5) This problem is due to the memory architecture of NVidia cards. It isn't the SETI@Home team's fault, so at least there's that. There's no malice or sloppy coding etc. behind it. If anything we should complain to NVidia as they are pushing CUDA as a scientific computing platform.

6) The GPUs run cooler and so will probably last longer.

7) Half the world can't even get enough food to eat, so we're pretty well off if this is all we have to worry about. Gotta mention this. :^)
3) Message boards : Number crunching : Average Credit Decreasing? (Message 1789620)
Posted 2 days ago by Profile Mr. KevvyProject donor
I was able to contact Dr. Eric Korpela. He indicated that a solution to allow GUPPI VLAR GPU work units to be refused in the Project Prefs. is being worked on. Please pass it along...

Hope this alleviates any of the misgivings that the project admins. aren't aware of this issue or don't care about it.
4) Message boards : SETI@home Science : SETI E.T. Search Radio Interference ?? (Message 1789591)
Posted 2 days ago by Profile Mr. KevvyProject donor
Radiotelescopes are usually located in radio-quiet zones to prevent interference, ie Green Bank's location was chosen as it is surrounded by hills. There are special restrictions in place ie no cell phones, diesel vehicles only (no spark plugs). Any machine noise in the area would be either below the horizon of the telescope or not be concentrated by the dish; it would have to strike the receiver directly and thus, at such a distance with inverse square propagation would be very weak perhaps even below the noise threshold. That frequency range doesn't bounce off the ionosphere either so wouldn't hit the dish by reflection.

So, I don't think it's much of an issue. I'm sure it would have been taken into account! :^)
5) Message boards : Number crunching : Average Credit Decreasing? (Message 1789560)
Posted 2 days ago by Profile Mr. KevvyProject donor
Since he is a member of the GPU Users Group perhaps some one with diplomatic skills could PM him and explain to him how is is screwing up SETI.


I'll pass the word. I thought it was this machine's owner but it turns out this is someone else doing the same thing. Shows 824 aborted GUPPIs.
6) Message boards : Number crunching : Average Credit Decreasing? (Message 1789284)
Posted 3 days ago by Profile Mr. KevvyProject donor
To add to what Chris wrote: at first there was much complaining that there was never enough work.... we were running out every Tuesday and not catching up until the next day, and plenty of other times as well.
Solved: the SETI@Home scientists built the GBT receiver and a new splitter and got on the Breakthrough Listen initiative, and now we have enough work (possibly even too much!)

Next, there was much complaining (including from myself) that CUDA GPUs weren't being assigned the new GBT work, though it's possibly far more likely to contain a candidate signal, and thus find something.
Solved: the same group beta-tested the impact to system stability/usability of these work units being run on CUDA GPUs and then released them (this was also probably necessary, because there is so much work and CUDA GPUs make up such a significant fraction of machines available to do it.)

Now, there is much complaining that this work is causing a reduction of credit. Sure, it's sad that our RAC is dropping, but it isn't anyone's "fault" except the NVidia engineers who designed the memory architecture of the CUDA-enabled cards, and it's the unintended side effect of something that was asked for. It isn't CreditNew or Dr. David Anderson's doing. Fixed credit won't solve it as 3x the complete speed still equals 1/3 the fixed credit over time. It needs a possibly complex, and possibly impossible, workaround in the SETI@Home client itself.

So, in the interim, be patient, enjoy the new science, and be happy that those GUPPI work units trade off three times the compute time for... I dunno... thousands of times the chance of actually finding something, and I'll take that tradeoff any day!
7) Message boards : Number crunching : Welcome to the 17 Year Club! (Message 1788987)
Posted 4 days ago by Profile Mr. KevvyProject donor
Missed mine five days ago... better late than never. Story of my life. :^)
8) Message boards : Number crunching : Average Credit Decreasing? (Message 1788817)
Posted 5 days ago by Profile Mr. KevvyProject donor
I'm just crunching for Milkyway for a week and already have a higher RAC, than i had here before...


And if I move to Mexico and get a job as a janitor my paycheque in pesos will be larger than it is currently in dollars.

There won't ever be a BOINC consistent credit payment across projects, because smaller or startup projects or those with not-so-interesting (or nigh-incomprehensible) goals overpay to attract volunteers, and will continue to do so.
9) Message boards : Cafe SETI : Thor is the Designer Cafe! (Message 1788769)
Posted 5 days ago by Profile Mr. KevvyProject donor
Yes Thor wants enthusiastic support.


Enthorsiastic!
10) Message boards : Cafe SETI : Thor is the Designer Cafe! (Message 1788737)
Posted 5 days ago by Profile Mr. KevvyProject donor
Ever sense you put this thread up my
province has had nothing but bad luck.
Please take it down!


Ahem. The Designer frowns upon being blamed for it. It's practically... Inthorbordination! :^D
11) Message boards : Cafe SETI : Thor is the Designer Cafe! (Message 1788529)
Posted 6 days ago by Profile Mr. KevvyProject donor
This thread needs to be warmed up...


Add Thormal energy to crank up the Thormometer! :^)
12) Message boards : Technical News : Data Dump (May 17 2016) (Message 1788250)
Posted 7 days ago by Profile Mr. KevvyProject donor
Dunno if you will see this, but may as well ask: with this huge volume of data, how much of it are we volunteers currently able to process? Are we keeping up or falling behind to what fraction?

And, sorry to sound like a broken record, but please let GPUUG know of any hardware needs! Haven't been tapped for a good fundraiser in a while, even though those we did were quite successful.
13) Message boards : Number crunching : Average Credit Decreasing? (Message 1787922)
Posted 8 days ago by Profile Mr. KevvyProject donor
very short version:
low AR => longer time to stare at same point => bigger data array for single PoT search => failure to fit cache, failure to get enough parallel data to fill all CUs (longer single array = less number of such arrays cause 1M matrix of data point remains constant)


OK, this helps. Since slewing Arecibo work units don't do this, the AR must be greater than the scope's "aperture". Let's say that the AR is 3x the size of the aperture of the scope.

Then why not break the WU into that ratio of pieces (in this case 3) and run the pulsefind on each piece, then add the results? That way each piece being of the same timebase as an Arecibo Gaussian won't overload the cache.

Edit: This will take some tinkering due to pulses at the edge of each piece that and up in both of them...
14) Message boards : Number crunching : Average Credit Decreasing? (Message 1787907)
Posted 8 days ago by Profile Mr. KevvyProject donor
For explanations why VLAR relatively harder for GPU vs CPU vs other ARs look few my recent posts for example (actually it was repeated few times through years).


Thanks for the details... do you have a link to any of these posts?
15) Message boards : Number crunching : Average Credit Decreasing? (Message 1787894)
Posted 8 days ago by Profile Mr. KevvyProject donor
Is it more of a driver issue (where we would have to wait for Nvidia to get their act together before there is any relief), the way that the Guppies are configured when they are split (something that can be addressed internally, though with the manpower crunch, is that likely anytime soon?), or something else that causes such a penalty for them on Nvidia hardware? Are things much better in the AMD world? I haven't ran a AMD card for probably 15+ years, so I basically have no experience with them.


I haven't checked the source code enough yet to know for sure, but I have a suspicion:

There's something in the CUDA framework that doesn't like that VLAR work units have negligibly small angular size. This should exclude them from even checking for Gaussians because the telescope is not crossing the signal which is what causes one, so any code which checks for Gaussians shouldn't even run in a VLAR.

The fact that it is running really slowly means that something in there is still using that angular size (what else but a Gaussian would need to use it?), and very likely shouldn't be. So, to find what the code is that does it, and don't run it if the angular width is below the VLAR threshold.

I'm going to try to bring myself up to speed to fix this thing, but I'm hoping someone will beat me to it... it's a lot of work getting there. :^)
Edit: Also when I get there I am not sure I will even recognize it when I see it...lol.
16) Message boards : Number crunching : Average Credit Decreasing? (Message 1787881)
Posted 8 days ago by Profile Mr. KevvyProject donor
Every time I look and see my rac dropping I keep thinking there's a problem then I remember Credit Screw


Not the cause anymore... it's now due to your exclusively NVidia farm receiving GUPPI VLAR work units on the GPUs. As noted much elsewhere, they process much more slowly than Arecibo MBs but pay the same credit.
17) Message boards : Number crunching : Windows 10, Chrome, Netflix stuttering now (Message 1787758)
Posted 9 days ago by Profile Mr. KevvyProject donor
As you have a 980 which is an NVidia card, the recent release of VLAR GUPPI work units for NVidia CUDA is probably causing the stuttering.

You can fix this under Tools:Computing Preferences by unchecking "Use GPU while computer is in use" and setting an appropriate time below. If you want the GPU computing to occur while the machine is being used, if you have edited app_config.xml and changed the <count> parameter to allow multiple work units to run on the GPU at once, it is suggested to increase the number to reduce the number of work units at once.
18) Message boards : Cafe SETI : A little bit of the kittyman's mind. (Message 1787618)
Posted 10 days ago by Profile Mr. KevvyProject donor
Yes, I know, and I'm sorry, but once Mark's post from that original thread re-emerges here, the context will be more clear.


Hey don't be... was just explaining for anyone who wondered what Carlos was doing randomly inserting that. :^)
19) Message boards : Cafe SETI : A little bit of the kittyman's mind. (Message 1787613)
Posted 10 days ago by Profile Mr. KevvyProject donor
People keep asking this question. What would Jesus Drive.


This post was spot-on in the now-hidden (and at the time empty) WWJD thread, but now makes no contextual sense whatsoever merged into this one.
20) Message boards : Number crunching : Question Of Meaning = SETI Is Useful Currently : Yes Or No? (Message 1787420)
Posted 11 days ago by Profile Mr. KevvyProject donor
Wait... they had a budget for duck tape?




Is this how scientific inducktion and deducktion is developed?


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