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Re: New to this, whats the best setup for a dual Xeon E5 269

PostPosted: Fri Dec 13, 2013 4:35 pm
by powerarmour
Just a quick question, I'm currently running bigadv on a pair of stock 2Ghz Xeon E5-2650's (Ubuntu 12.04 x64) for around 280k PPD, is that about the right sort of ballpark performance I should be expecting?

Re: New to this, whats the best setup for a dual Xeon E5 269

PostPosted: Sat Dec 14, 2013 5:46 pm
by Nathan_P
powerarmour wrote:Just a quick question, I'm currently running bigadv on a pair of stock 2Ghz Xeon E5-2650's (Ubuntu 12.04 x64) for around 280k PPD, is that about the right sort of ballpark performance I should be expecting?



You are doing well, my E5-2665's @2.45 are only getting about 260k.

Re: New to this, whats the best setup for a dual Xeon E5 269

PostPosted: Mon Dec 23, 2013 11:33 am
by Napoleon
IMHO, the OP would be better off with a single CPU:24 slot. We're talking about 24-core / 48-thread dual-socket system here, right? It has only 24 FPUs anyway, so there shouldn't be that big a difference (in TPF) between a fully dedicated CPU:48 slot and a fully dedicated CPU:24 slot because FAH is extremely FPU-intensive.

Load balancing is important, and a single CPU:24 potentially loads all the FPUs evenly. If not, the OP could check the logical vs physical CPU mappings with CoreInfo and apply some affinity tweaks - viewtopic.php?f=59&t=17881 as an example.

FAH may or may not interfere with other apps. If said apps aren't FPU intensive, the impact is fairly small. Worst case is an FPU-intensive app which does not use all 48 logical CPUs.

Re: New to this, whats the best setup for a dual Xeon E5 269

PostPosted: Mon Dec 23, 2013 6:06 pm
by bruce
Napoleon wrote:IMHO, the OP would be better off with a single CPU:24 slot. We're talking about 24-core / 48-thread dual-socket system here, right? It has only 24 FPUs anyway, so there shouldn't be that big a difference (in TPF) between a fully dedicated CPU:48 slot and a fully dedicated CPU:24 slot because FAH is extremely FPU-intensive.

Load balancing is important, and a single CPU:24 potentially loads all the FPUs evenly. If not, the OP could check the logical vs physical CPU mappings with CoreInfo and apply some affinity tweaks - viewtopic.php?f=59&t=17881 as an example.


Your theory has merit. I have a different theory. In either case, Grandpa_01 said he was going to do some testing. I don't remember seeing definitive test results.

Suppose you hava 24-core / 48-thread dual-socket system as you suggest and you set affinity for 24 dedicated FPUs. Compare that to 25 threads where two have to share a FPU (for this discussion, assume 25 is not one of the excluded numbers). Based on tests of the original dual-thread Pentium, two threads sharing a FPU will get 15-20% more total work done than a single thread. (FAH is extremely FPU-intensive but contains some percentage of non-FPU instructions.) DLB should recognize those two CPUs are slower than the rest if they're affinity locked and redistribute the work based on 60% + 60% + 100% + 100% + ... + 100% and get a little more work done. By induction, 40 threads (or some large dedicated number that actually works) should be better than 24.

Like Plato's observations, this is pure theory, not (yet) verified by test. And, since we're talking HT here, the difference between 24 and 40 (or 36 or ...) will be small. The real worst case is when some threads are dedicated at times and not dedicate at other times, causing DLB to get things wrong or you're oversubscribed mandating that there is no ideal DLB pattern to be found.

Re: New to this, whats the best setup for a dual Xeon E5 269

PostPosted: Thu Dec 26, 2013 11:00 pm
by Napoleon
Normally I would've recommended something a bit more ambitious than CPU:24 (optionally with affinity tweaking), but the OP prefers to stick to Windows only and the setup isn't dedicated to folding - viewtopic.php?p=250092#p250092 as a reminder.

Therefore, no BigAdv, maximum of 32 logical CPUs (per slot), and the OP is likely to receive A4 WUs among others. I've tested with my Linux setup fairly recently, and I couldn't get DLB to engage on some A4 WUs, even if I tried introducing various amounts of load imbalance using a synthetic load. I also figured restricting to CPU:24 will leave the AS a bit wider variety of vanilla SMP projects to choose from.

Re: New to this, whats the best setup for a dual Xeon E5 269

PostPosted: Wed Apr 23, 2014 1:05 pm
by lundrog
I am doing the following.

<!-- Folding Slots -->
<slot id='0' type='SMP'>
<client-type v='bigadv'/>
<max-packet-size v='big'/>
</slot>
<slot id='1' type='SMP'>
<client-type v='bigadv'/>
<max-packet-size v='big'/>
</slot>

Getting the following with 12x 2p servers.

These are all running linux.

Image

Re: New to this, whats the best setup for a dual Xeon E5 269

PostPosted: Wed Apr 23, 2014 3:45 pm
by PantherX
Since you are using the bigadv setting, I would suggest that you set one of the CPU Slot to finish. Once finished, remove that CPU Slot. The other CPU Slot which remains, change the CPU Value from 24 to 48 so that all CPUs can be used by a single bigadv WU. Since you have 48 CPUs in a single system, you configuration would be similar to this:
<!-- Folding Slots -->
<slot id='0' type='SMP'>
<cpus v='48'/>
<client-type v='bigadv'/>
<max-packet-size v='big'/>
</slot>

Generally speaking, it is better for a single CPU Slot to use as many CPUs you can dedicate to folding as possible.