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-   -   Welcome Ben Delo (https://www.mersenneforum.org/showthread.php?t=24819)

petrw1 2019-10-08 05:24

Welcome Ben Delo
 
He's been completing DC and LL by the bucket loads the last few months.

WOW!!!

Uncwilly 2019-10-08 06:06

Are the DC's on the same exponents as the LL?
Not suggesting that there is anything untoward going on, just saying "доверяй, но проверяй" (doveryay, no proveryay) ["Trust, but verify"].

nomead 2019-10-08 08:35

They seem to be genuine DCs, at least the few that I manually looked through. The computer names remind me a lot of Amazon instance names, though... C4_8XL, C5_24XL, C5_METAL :smile:

ixfd64 2019-10-08 16:32

This user appears to be [I]the[/I] Ben Delo: [url]https://en.wikipedia.org/wiki/Ben_Delo[/url]

Assuming that's him, then we've got a billionaire in our ranks!

Ben Delo 2019-10-09 06:03

Thank you for the welcome. I have some spare AWS credit that I thought I would put towards GIMPS. Please do verify my results as I am still experimenting with different instance types and configurations.

GP2 2019-10-09 15:20

[QUOTE=Ben Delo;527576]Please do verify my results as I am still experimenting with different instance types and configurations.[/QUOTE]

AWS instance use ECC memory. Based on past experience it's extremely unlikely that you'll get any incorrect results.

The c5 instances use AVX-512 and have more cache, so they run mprime considerably faster than c4 instances. The c5n and c5d can also be used.

It's better to run multiple instances of the one-core c5.large, or at most the two-core c5.xlarge, rather than fewer many-core instances, because then the multiple cores on the same physical machine will contend with each other for memory access and bring your throughput way down.

Note that in AWS terminology, "two vCPUs" means a single core with hyperthreading. The mprime program is highly optimized and gets no benefit from hyperthreading.

mrh 2019-10-09 17:14

The C5 instances work very well. I always have some spot instances running. Those c5.metal instances are kinda pricey for me though. :smile: They must have a lot of memory channels since even the c5.9xlarge show no signs (that I could see) of any contention for memory.

GP2 2019-10-09 17:48

[QUOTE=mrh;527613]They must have a lot of memory channels since even the c5.9xlarge show no signs (that I could see) of any contention for memory.[/QUOTE]

Hmmm... it was true of the c4's, but I didn't really benchmark the c5's carefully.

One issue is that if you run separate one-core c5.large instances, then AWS might still end up running them on the same physical hardware, especially if you start them all at the same time. I'm not sure if there's any way you can tell.

Maybe staggered starts help, but you might need to use a pretty long interval to be on the safe side.

ewmayer 2019-10-09 19:37

[QUOTE=Ben Delo;527576]Thank you for the welcome. I have some spare AWS credit that I thought I would put towards GIMPS. Please do verify my results as I am still experimenting with different instance types and configurations.[/QUOTE]

Ah, the lights just went on - I figured the name "Delo Ben", the rendering of your name in the Paypal e-mail I got, was some kind of semi-anglicized Asian name. Thanks again for the generous donation, and for the compute cycles! IIRC the last time GIMPS saw a rough doubling of daily throughput it was due to a bunch of LL results from a fellow using my Mlucas code to stress test a bunch of ARM-based servers, but that was a 1-day deal. How many LL tests do you estimate your AWS credits to amount to?

tServo 2019-10-09 23:38

[QUOTE=petrw1;527499]He's been completing DC and LL by the bucket loads the last few months.

WOW!!![/QUOTE]

The statistics from the Primenet reports page are AWESOME:

211 DCs and 818 1st time LLs in the past 90 days; 90% of this work was done in the last 30 days !!!!!

Thanks, indeed Ben.

Ben Delo 2019-10-10 05:59

[QUOTE=GP2;527617]Hmmm... it was true of the c4's, but I didn't really benchmark the c5's carefully.

One issue is that if you run separate one-core c5.large instances, then AWS might still end up running them on the same physical hardware, especially if you start them all at the same time. I'm not sure if there's any way you can tell.

Maybe staggered starts help, but you might need to use a pretty long interval to be on the safe side.[/QUOTE]

Yes I found that running 50x c5.metal was better than 2400x c5.large, but I will keep experimenting.


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