Hello!
I've recently been bouncing around a few projects after supporting WCG for a pretty solid year, owing mostly to the fact that I had very little GPU power - and Folding at home really made me feel inadequate in comparison.

Now that I finally am able to grab myself a GTX 1080, I figured I would pop on here to get my machines into the mix.

So now for my questions.

I notice there is only one type of task - Amicable Numbers up to 10^20. Does this apply to both CPU and GPU? What are the general deadlines, as I have a few less powerful processors - think Intel Atom x5. How about GPU requirements? They range from the aforementioned GTX 1080 to an rx570 and Geforce 670M (surprisingly that laptop is still hammering out WUs without a battery for the last 3 years...)

And, finally, does this project support multithreading? If not, is it more productive to have hyperthreating / SMT on Intel and AMD processors disabled/use 50% CPU in the boinc client?

Regardless, I look forward to joining this community! I plan on trying out a few different projects now that I don't feel completely left in the dust. :)

Hi wolfman1360!

And welcome to Amicable Numbers! Unfortunately for your new GTX 1080 GPU workunits are extremely inefficient at the moment as the vast majority (99%+) of the calculations performed for each workunit are done by the CPU. This will change in a month or two when we finish searching up to 10^20 and begin the search up to 10^21. Until that time it is still possible to run GPU workunits, however you will not be able to fully utilize the GTX 1080 even with a very powerful CPU and as many workunits as you have threads on that CPU. Instead; you can run the CPU version of the program here and it has an excellent credit/day throughput compared to almost any other project.

If you would like to participate in Amicable Numbers to help finish the search to 10^20 faster and get to those GPU-efficient 10^21 workunits faster my recommendation would be to run CPU workunits here, and then put the GPU power towards something like Collatz or the AP27 or GFN-21/22 workunits over at PrimeGrid. Those use very little CPU to run efficiently on a GTX 1080. Then, once we begin the search to 10^21, switch the GTX 1080 over to here and watch the credits pile in :)

Regards,
Kellen

Hi wolfman1360!

And welcome to Amicable Numbers! Unfortunately for your new GTX 1080 GPU workunits are extremely inefficient at the moment as the vast majority (99%+) of the calculations performed for each workunit are done by the CPU. This will change in a month or two when we finish searching up to 10^20 and begin the search up to 10^21. Until that time it is still possible to run GPU workunits, however you will not be able to fully utilize the GTX 1080 even with a very powerful CPU and as many workunits as you have threads on that CPU. Instead; you can run the CPU version of the program here and it has an excellent credit/day throughput compared to almost any other project.

If you would like to participate in Amicable Numbers to help finish the search to 10^20 faster and get to those GPU-efficient 10^21 workunits faster my recommendation would be to run CPU workunits here, and then put the GPU power towards something like Collatz or the AP27 or GFN-21/22 workunits over at PrimeGrid. Those use very little CPU to run efficiently on a GTX 1080. Then, once we begin the search to 10^21, switch the GTX 1080 over to here and watch the credits pile in :)

Regards,
Kellen

Thank you for that info, this is great to know.
I do have quite a few decent CPUs here - A ryzen 7 and Ryzen 7 pro as well as a few i7's. I was with Prime Grid for a while but the CPU part of crunching there got very confusing (some multithreaded, some did better with hyperthreading, some not...), so maybe I'll just start going on with GPUs on there.
I certainly will enjoy the credits accumulating here.

Some observations now that I have 1 or 2 machines connected.
This project seems to eat up tons of ram - my Ryzen 1800x is hovering right around 12 GB of 16 GB used, with Amicable_v_2_1_8.exe taking over 9 GB of that.
Goodness, GPU computing sure isn't efficient - anywhere from 2-4% utilization when running 1 GPU task - I'd never be able to have enough cores or threads available, or the ram bandwidth, to actually get it to 100%. I know it was already mentioned here, but I wanted to see what it did. I've since switched GPU computing over to Collatz.
I love that this is multithreaded, though, and doesn't require tons of monitoring or changing CPU preferences when I change projects to run (or am I wrong - there is only one project here I suppose, to be fair).

Would it be worth my while to tick run test projects? I don't see anything in the forums mentioning new ones, but am curious.

Anything else I should keep in mind? To get an idea of CPUs that I'm using, just in case I might run into ram usage issues down the road. I'm very new to multithreaded (using all cores available).

Core 2 duo e8400
Core i5-3317U (not crunching 24/7)
Core i5-2600
Core i7-7700
Core i7-8750h (not crunching 24/7)
Core i7-3610QM
Ryzen 7 1800x and ryzen pro 1700x.

If I do start using tons of swap, will this honor boinc CPU settings when I lower the usage? These Ryzen's seem to be doing very good so far - in this project, unlike Prime Grid where Intel takes the clear lead in most cases (lacking in certain instruction sets, I think)?

Sorry if these questions seem obvious. I'd just like my CPU cycles to be crunched as optimally as possible.
Thank you for the help so far.

Hi wolfman1360,

You are definitely correct about the RAM usage right now! The total RAM used is approximately 650MB per thread, so if you are running 16 threads on you 1800X that would get you into the 10GB neighborhood. This is also a by-product of the present search stage, where we are looking at candidates containing very large prime numbers. RAM usage will continue to climb gradually until the end of the search to 10^20, but will drop significantly once 10^21 search begins.

To the best of my knowledge there are presently no test applications running, so I don't think enabling that would do anything right now. It might if Sergei gets the 10^21 app loaded and tested before 10^20 is complete, but I would expect that is some time off and would only be for a short while.

Nothing really to keep in mind with multi-threading for this project. The multi-threading implementation is pretty straightforward and tends to work well with default settings. Something to note though is that if you are running a task with a set number of threads, lets say 16, and you set CPU usage in BOINC to 50% on your 1800X, the 16-thread task will continue to run with 16 threads, using 100% of your CPU, until it is complete, then the next task you receive will be an 8-thread task.

Over at PrimeGrid you are correct that many Intel CPUs have a clear advantage over Ryzen and that is predominantly related to the AVX portion of the CPU. Intel CPUs have a 256-bit width for the AVX processing and 1st and 2nd generation Ryzen CPUs only have 128-bit width. The 3rd generation Ryzen CPUs have 256-bits though, so they are comparable with most Intel CPUs (well; except for the high end Intel CPUs which have AVX512 support, which are in a league of their own for the LLR tasks). Thankfully, this does not affect the processing speed here at Amicable Numbers :D

Hope this helps! Enjoy crunching! :)

Regards,
Kellen

Hi wolfman1360,

You are definitely correct about the RAM usage right now! The total RAM used is approximately 650MB per thread, so if you are running 16 threads on you 1800X that would get you into the 10GB neighborhood. This is also a by-product of the present search stage, where we are looking at candidates containing very large prime numbers. RAM usage will continue to climb gradually until the end of the search to 10^20, but will drop significantly once 10^21 search begins.

To the best of my knowledge there are presently no test applications running, so I don't think enabling that would do anything right now. It might if Sergei gets the 10^21 app loaded and tested before 10^20 is complete, but I would expect that is some time off and would only be for a short while.

Nothing really to keep in mind with multi-threading for this project. The multi-threading implementation is pretty straightforward and tends to work well with default settings. Something to note though is that if you are running a task with a set number of threads, lets say 16, and you set CPU usage in BOINC to 50% on your 1800X, the 16-thread task will continue to run with 16 threads, using 100% of your CPU, until it is complete, then the next task you receive will be an 8-thread task.

Over at PrimeGrid you are correct that many Intel CPUs have a clear advantage over Ryzen and that is predominantly related to the AVX portion of the CPU. Intel CPUs have a 256-bit width for the AVX processing and 1st and 2nd generation Ryzen CPUs only have 128-bit width. The 3rd generation Ryzen CPUs have 256-bits though, so they are comparable with most Intel CPUs (well; except for the high end Intel CPUs which have AVX512 support, which are in a league of their own for the LLR tasks). Thankfully, this does not affect the processing speed here at Amicable Numbers :D

Hope this helps! Enjoy crunching! :)

Regards,
Kellen

Thank you very much for the informative response, and that makes total sense. My more powerful machines are predominantly AMD so I'd rather use them where their power is best able to make a difference :)
I may grab a 32 GB kit for the 1800x just so I have a bit of headroom. Looking good for October being the estimated end date for this series, though, and I look forward to seeing the numbers increase.
thanks again.

I plan to add 10²¹ app before October, I just haven't figured out the optimal way to run 10²¹ search yet. I need to go through current search results and find the most juicy subsets of tasks to run first. I think something like "searching through all odd numbers with largest prime factor < 10¹¹" can yield over a million new pairs in a year or two.

I plan to add 10²¹ app before October, I just haven't figured out the optimal way to run 10²¹ search yet. I need to go through current search results and find the most juicy subsets of tasks to run first. I think something like "searching through all odd numbers with largest prime factor < 10¹¹" can yield over a million new pairs in a year or two.

Nice! Definitely looking forward to this! And I like the search methodology too; the first portion of the search up to 10²⁰ was quite exciting with the frequency of amicable pair finds. Once the large prime workunits started the excitement died down quite a bit, lol. I've been stuck at 24,311 pairs for a very long time; can't wait to bump that up!

On a somewhat unrelated topic, now that we have gotten very close to the "ETA at current speed (search up to 10²⁰)" stat on the Project Status page, would it be possible/difficult to switch this over to a number of days remaining? It will bounce around a bit, but should be relatively stable now that we are so close.

Regards,
Kellen

would it be possible/difficult to switch this over to a number of days remaining?

Awesome, thanks!! Nice to see the date in full form :)

Regards,
Kellen

Hello.
I do have one question.
In The Amicable Numbers preferences, there is an option for number of CPUs.
Does this equate to how many cores get used per task? E.g. if I set it to 8 CPUs 8 out of 16 threads will be used on this Ryzen?
thanks.

Hello.
I do have one question.
In The Amicable Numbers preferences, there is an option for number of CPUs.
Does this equate to how many cores get used per task? E.g. if I set it to 8 CPUs 8 out of 16 threads will be used on this Ryzen?
thanks.

Hi wolfman1360,

You are correct that it is the number of cores used per task. If you set it to 8 CPUs, but leave BOINC's CPU usage at 100%, it will have the effect of running two tasks at the same time with 8 threads each. I do this on my Ryzen 5 1600X so that I can pause tasks if I need some CPU power for something else, without having to stop all crunching for Amicable Numbers. I have my 1600X set up to run tasks with 3 threads each, so that I can easily change how much of my CPU is being used (0%, 25%, 50%, 75% or 100%) whenever convenient.

If you would like to limit your computer to running just a single task with 8 threads you can do that in the options here by limiting that computer to only having 1 workunit at a time, setting CPU usage to 50% in BOINC, or by making an app_config file with the following in it;

<app_config>
<app>
<name>amicable_10_20</name>
<max_concurrent>1</max_concurrent>
</app>
</app_config>

Hope this helps!

Regards,
Kellen

Hello.
I do have one question.
In The Amicable Numbers preferences, there is an option for number of CPUs.
Does this equate to how many cores get used per task? E.g. if I set it to 8 CPUs 8 out of 16 threads will be used on this Ryzen?
thanks.

Hi wolfman1360,

You are correct that it is the number of cores used per task. If you set it to 8 CPUs, but leave BOINC's CPU usage at 100%, it will have the effect of running two tasks at the same time with 8 threads each. I do this on my Ryzen 5 1600X so that I can pause tasks if I need some CPU power for something else, without having to stop all crunching for Amicable Numbers. I have my 1600X set up to run tasks with 3 threads each, so that I can easily change how much of my CPU is being used (0%, 25%, 50%, 75% or 100%) whenever convenient.

If you would like to limit your computer to running just a single task with 8 threads you can do that in the options here by limiting that computer to only having 1 workunit at a time, setting CPU usage to 50% in BOINC, or by making an app_config file with the following in it;

<app_config>
<app>
<name>amicable_10_20</name>
<max_concurrent>1</max_concurrent>
</app>
</app_config>

Hope this helps!

Regards,
Kellen

Thank you.
I only bring this up as ram is a little tight on this machine right now with all 16 threads crunching on Amicable numbers. Am I okay to allow tasks to leave memory when the computer is in use?
I'll play around with the various settings and see what offers a decent compromise for the time being until I get a chance to replace this ram with not only more but hopefully faster, too.