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For most computer uses, 80 threads is a solution in search of a problem.
Some engineering and math problems are crying for massive parallelism, with weather forcasting as the primary schoolbook example. All the top supercomputers in the world are hugely, massively, parallell.
But for everyday desktop problems, it is next to impossible to split the task into 80 similar-size, independent subtasks. One action follows the other, and if you manage to split it into eight or ten action sequences (or threads), most of the time a few of them will be idling waiting for one of the others to catch up. The more threads you create, the greater is the chance that a large fraction of them will be idling.
Then, if you manage to run 80 threads at full speed for an extended period of time: In most cases, they wil block on some other resource, probably I/O capacity. When my old university got their first Cray supercomputer in the early 1980s, it didnt last more than a couple of years: The processing capacity of the CPU was more than sufficient for FEM and weather forcasting, but the CPU was idling waiting for the raw data to come into memory; the I/O channels were not wide enough. Its replacement (a newer Cray) didn't have a much faster CPU, but significantly improved I/O, giving a dramatic improvement in throghput. Look at today's supercomputers: Not only do they have massively parallell processing, but also massively parallell I/O. And by building the machine from several thousand processing nodes, the combined RAM access capacity is immense. The individual CPU chips are not very impressing at all.
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My guess is that they're using it for VMs.
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Joe Woodbury wrote: My guess is that they're using it for VMs.
I was going to point that out. I have dozens of VMs running on consumer hardware, and while it's never starved for CPU time, it sure would be nice if it could dedicate a couple of threads to each VM.
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Member 7989122 wrote: For most computer uses, 80 threads is a solution in search of a problem.
Yes, this is true. In our case, we have a very well-defined problem that benefits nicely from lots of threads. Until now, we could't get enough threads in one box so we distributed the calculations across multiple computers. We hope this one will allow us to use just one box at half the cost of the multiple machines and a small fraction of the rackspace - 1U vs. 4 or 5 4U boxes.
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Rick York wrote: Unfortunately, I seem to be seeing a bug with the OMP library. It doesn't seem to handle that many threads correctly.
Are you are actually trying to implement a single process with 80 threads... ? If so... why?
Hopefully you are just testing to see what happens.
Best Wishes,
-David Delaune
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Maybe I did not use 80 threads, but at times I have a few of them. Rendering, UI, message queue, application thread, async calculations, async database queries...
Just a game[^]
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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The single process will use around 65 or 70 threads. We do this because it will be a much more efficient solution than distributing the sixty+ threads across four or five different machines as we do now. We want to to eliminate the steps of distributing the calculation parameters across the network and collecting the results.
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Randor wrote: Are you are actually trying to implement a single process with 80 threads... ? If so... why?
It all depends on what these threads are doing. Here's a real-world example:
I have a tiny utility sitting in my system tray that runs many small WMI queries across my LAN to refresh hardware configuration data from remote machines at startup. The payload is very small, so the LAN can take it, but WMI queries are inherently very slow, so it made sense here to dedicate not only one thread per machine, but one thread per query (each machine runs maybe a dozen WMI queries). Multiply that by a dozen machines, and it very quick adds up.
What used to be a queued set of queries that took 10+ minutes to complete is now a bunch of threads starting in parallel and all completing within 30 seconds.
[Edit]
Of course this doesn't imply I need an 80-core machine to run this.  Just saying it's not all that unreasonable to spawn this many threads, even if just for a limited time.
modified 29-Jun-18 10:36am.
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That's cute.
AMD just gave Intel the finger with the announcement of the 2nd gen Threadripper. 32 cores, 64 threads, and 250W of heat to get rid of.
Drop of a couple of those on a motherboard.
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I would love to give one of those a try. I think it would work really well with our application. The application is known in our industry as "primary breakdown optimization." A search at google will turn up lots of results, none of which is us because we are a privately held company and we do this for internal consumption only. It is a very mathematics-heavy application that gets its input data from LASER scanners.
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Ryzen is pretty cool, but it's not very good at 256bit vector arithmetic (gets split into two 128bit operations) so for math-heavy applications it can easily disappoint.
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Dave Kreskowiak wrote: and 250W of heat to get rid of.
I've only ever owned one AMD-based system. I called it the space heater.
I see they still haven't dealt with the one reason I was happy to get rid of it. With an expected high of 35C (excluding humidity) over the weekend, I'll happily continue ignoring AMD's latest offerings.
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I hear that. I've got a 6700K in my machine, running 24x7, and it does a nice job keeping the office warm at 95W(?)
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Rick York wrote: twenty hyperthreaded cores
The first systems I worked on, the word core meant a single bit in memory. You could actually open the memory cabinet and see the cores threaded on a matrix of signal wires.
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Ah - the knitting - I don't remember it, but my brother does from when he worked at Ferranti
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You could learn a lot about the internals of a computer just by looking inside. We also had the flashing lights panel so you could actually watch values being loaded into registers and manipulated. And best of all it could actually do financial calculations in £sd.
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Is graphic violence two fighting statisticians?
Sent from my Amstrad PC 1640
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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No, but it is a numbers game...
Keep your friends close. Keep Kill your enemies closer.
The End
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I thought it was two comic book authors fighting.
I'm not sure but it should be rated R, or PG-13 at least.
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There's certainly a decent probability
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Since you axis, we say Nay! As charter members of their guild, they feel themselves to be better betters. Then, as the plot thickens, they bar the other lines of thought.
| Ravings en masse^ |
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| "The difference between genius and stupidity is that genius has its limits." - Albert Einstein | | "If you are searching for perfection in others, then you seek disappointment. If you are seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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That’s not a lie. That’s not even a damned lie...
I'm pretty sure I would not like to live in a world in which I would never be offended.
I am absolutely certain I don't want to live in a world in which you would never be offended.
Freedom doesn't mean the absence of things you don't like.
Dave
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That's average at best. Sorry, I'm in mean mode today.
98.4% of statistics are made up on the spot.
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Stop fighting, let's be extrapolate.
... such stuff as dreams are made on
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Software Zen: delete this;
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