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#101 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,426
Rep Power: 49 ![]() ![]() |
I somehow find it hard to believe that you get 100% scaling from 2xSMT. Especially for this kind of application. We already see diminishing returns up to 44 threads.
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#102 | |
New Member
Timothy Pearson
Join Date: Jul 2018
Location: United States
Posts: 6
Rep Power: 8 ![]() |
Quote:
Looking in to StarCCM+, it looks like it is only available for x86 machines? If Siemens is willing to consider a recompile for ppc64el we could then run benchmarks against it. We are seeing more and more vendors start offering ppc64el builds of their software, so it probably wouldn't hurt to ask them. EDIT: Yep, something went wrong in the meshing stage, but the benchmark did not halt or otherwise indicate there was a problem. Had to dig around in the log files due to the suspiciously good numbers. Looks like ~30s is the best time we have thus far. Last edited by tpearson-raptor; July 27, 2018 at 05:45. |
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#103 | |
Senior Member
Join Date: May 2012
Posts: 551
Rep Power: 16 ![]() |
Quote:
I have also experienced ridiculous numbers (like 2 seconds on a 7600k CPU) when playing around with the script file (number of cores being used mostly). Did you find any information in the log files that reveal any strange behavior? |
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#104 | |
Senior Member
Joern Beilke
Join Date: Mar 2009
Location: Dresden
Posts: 511
Rep Power: 20 ![]() |
Quote:
StarCCM+ was just an example as a code which is not available as native port. POWER is usually very good in running VirtualMachines. So my question is, how good do the the Intel/Amd ports run in a virtual environment. You might tell us how this benchmark behaves in a VM. |
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#105 |
Senior Member
Join Date: Mar 2009
Location: Austin, TX
Posts: 160
Rep Power: 18 ![]() |
Did Siemens can the Power and Itanium ports of Star-CCM+? CD-adapco had them before the acquisition.
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#106 |
Senior Member
Join Date: May 2012
Posts: 551
Rep Power: 16 ![]() |
Here are some results from my old home computer.
I played around with over-clocking the CPU and the memory and it turns out (not surprisingly perhaps) that over-clocking the CPU has little to no influence on the CFD performance. It would be interesting to see if going to 4000+ MHz memory modules scales as well as 2133 to 3200 MHz does. 2400 MHz memory was much faster compared to 2133 MHz (not really linear increase but almost). I think my results can be extrapolated fairly well to the 8700k with 3200 MHz memory. Note that I also under-clocked the CPU to 3 GHz (using 2400 MHz memory), which further points to the extreme benefit of faster memory rather than a faster CPU. ------------------------------------------------------- core i7-7600K, DDR4 2133 MHz CL 15 # cores Wall time (s): ------------------------ 2 423.92 4 357.42 core i7-7600K, DDR4 2400 MHz CL 15 # cores Wall time (s): ------------------------ 2 389.9 4 322.65 core i7-7600K, DDR4 2400 MHz CL 13 # cores Wall time (s): ------------------------ 2 388.86 4 320.97 core i7-7600K @ 4500MHz, DDR4 2400 MHz CL 15 # cores Wall time (s): ------------------------ 2 385.99 4 319.42 core i7-7600K @ 4700MHz, DDR4 2400 MHz CL 15 # cores Wall time (s): ------------------------ 2 379.26 4 321.16 core i7-7600K @ 3000MHz, DDR4 2400 MHz CL 15 # cores Wall time (s): ------------------------ 2 441.56 4 334.5 |
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#107 |
New Member
Tarik Ghattas
Join Date: Dec 2015
Location: Brazil, SP
Posts: 3
Rep Power: 10 ![]() |
Hello! Got a macbook pro 13" 2018 model to test some stuff and here's CFD Benchmark results for it. So, before that, it's running a Intel Core i5 8259U 28W Coffee Lake U CPU with base clock of 2.3 GHz and Turbo up to 3.8GHz. It has 8GB LPDDR3 2133 MHz memory. Benchmark was done post the supplemental update to correct thermal issues. I used Openfoam v5 under Docker for Mac.
Code:
SnappyHexMesh results: Cores Real time 1 18m25.925s 2 13m39.983s 4 9m53.062s Benchmark results: # cores Wall time (s): ------------------------ 1 729.07 2 410.78 4 370.82 |
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#108 |
New Member
Join Date: Nov 2016
Posts: 15
Rep Power: 9 ![]() |
Hello,
Here is the benchmark result with my PC : i7 6950x@3.5GHz (slightly OC) - 4 x8Gb DDR4 @ 3000Mhz. I am using Windows 10 and OpenFoam installed on bash Code:
# cores Wall time (s): ------------------------ 4 249.42 6 184.3 8 167.84 10 163.67 I am using CPU cooler: Thermalright true spirit 120m (cost around 35$). Is it a problem? The CPU temperature at full load of 10 cores are around 75 degree Celsius |
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#109 |
Senior Member
Join Date: May 2012
Posts: 551
Rep Power: 16 ![]() |
75 degrees is probably fine (noise levels might be a problem though). I would try to limit OC the CPU and try to max out the memory instead. If you add more voltage to the memory then a case fan directed at the memory can help a lot.
The best suggestion is to search for a dedicated tutorial on the 6950X and overclocking (there are several) and to approach the matter with caution since you can fry the components. ![]() |
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#110 | ||
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,978
Blog Entries: 45
Rep Power: 128 ![]() ![]() ![]() ![]() ![]() ![]() |
Quote:
Quote:
Last edited by wyldckat; August 20, 2018 at 14:09. Reason: fixed typo |
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#111 | ||
New Member
Join Date: Nov 2016
Posts: 15
Rep Power: 9 ![]() |
Quote:
Quote:
Thank you for all of your replies! So Should I change the cooler ? Actually I have turned off HT. My RAM is designed to work at 3000MHZ and the stock speed of 6950x is 3.0GHz. By default the RAM works at 2132MHz and to get 3000 MHz, I have to activate XMP profile. Also to get CPU works at 3.5 GHz, I also increase CPU cache, otherwise the CPU works at 3.0GHz only! By the way, how do you think of my Benchmark result! I think it is quite similar to 7820x result and a little better than 7900x. But I see the quite much improvement of 7820x after RAM timing tweak, so I am curios that I can do the same for my system ? |
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#112 |
Senior Member
Join Date: May 2012
Posts: 551
Rep Power: 16 ![]() |
I would continue to play around with the memory but don't go crazy on the voltage. Just test to increase the frequency and try to decrease the timings if it doesn't work. Baby steps
![]() Regarding the temperatures, here is a reasonable read: http://www.tomshardware.co.uk/forum/...ure-guide.html The cooler you have might not be the best, but try to use stock operation first and compare to the benchmark results before you go out and buy another heatsink. If you still have 70+ degrees when running then you can change (corsair hydro series is a really nice option). I think your results seem nice so be happy even if you can't manage higher memory speeds ![]() |
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#113 | |
New Member
Join Date: Nov 2016
Posts: 15
Rep Power: 9 ![]() |
Quote:
Thank you! I will try to play with the memory. If the system is not stable I will just stick with current configuration. I will update the result soon! |
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#114 | |
New Member
Join Date: Nov 2016
Posts: 15
Rep Power: 9 ![]() |
Quote:
I have OC the memory a little bit, here is the result i7 6950x @3.5Ghz, RAM OC @ 3250Mhz 16-18-18-36 (XMP profile 3000 Mhz 15-17-17-35) Code:
# cores Wall time (s): ------------------------ 8 156.36 10 152.68 The result is good for me But there is a strange thing that I do not understand. The first time I change RAM frequency and timing to 3250Mhz 16-18-18-36. I got unbelievable result like this Code:
# cores Wall time (s): ------------------------ 8 139.26 10 105.67 Code:
# cores Wall time (s): ------------------------ 8 156.36 10 152.68 |
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#115 |
Senior Member
Join Date: May 2012
Posts: 551
Rep Power: 16 ![]() |
If it seems too good to be true, it generally is
![]() You should check the log file and make sure that the solver has done a full 100 iterations. If it crashes it gives no indication and the results are posted from the time of crash. So this just means that you have an unstable system and that you should try to tune it down a little bit. |
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#116 | |
New Member
Join Date: Nov 2016
Posts: 15
Rep Power: 9 ![]() |
Quote:
![]() Anyway, the current result is good for me now, because I just bought this second hand 6950x with price of 450$ |
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#117 | |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,978
Blog Entries: 45
Rep Power: 128 ![]() ![]() ![]() ![]() ![]() ![]() |
Just a quick note about this:
Quote:
Keep a close look at your Task Manager, in the Performance tab (if I remember correctly) and confirm at what clock speed the CPU is actually running, because Windows 10 does show that value with a fairly good accuracy. |
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#118 |
Senior Member
Join Date: May 2012
Posts: 551
Rep Power: 16 ![]() |
I ran into similar strange results when overclocking too excessive on my 7600k. I believe this is due to the script is not displaying solver information in the terminal. Due to this we are not alerted when an error occurs and since the "time" terminal command is not connected to the solver it has no way of casting an error.
I have modified the original script to repeat the calculations three times (at least) and also to avoid re-meshing on the second and third simulation. You could do the same to really check that your OC setup is stable. With stable configurations the fluctuations are of the order a couple %. If you wish to check for thermal throttling then you can use the "top" command as well as Code:
lscpu | grep MHz Code:
dmidecode -t 17 |
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#119 | ||
New Member
Join Date: Nov 2016
Posts: 15
Rep Power: 9 ![]() |
Quote:
Quote:
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#120 |
Senior Member
Join Date: May 2012
Posts: 551
Rep Power: 16 ![]() |
Here's the modified script file. There is no fail-safe to check if the meshes exist so you have to run the cases at least once before using this. It is reasonably easy to add that check though.
Code:
#!/bin/bash for (( t=0; t<3; t++ )); do # Clear old data for i in 2 4; do cd run_${i} if [ -d ./100 ]; then # Control will enter here if $DIRECTORY exists and delete it if so. rm -r 100 fi x=${i} for (( c=0; c<x; c++ ));do if [ -d ./processor${c} ]; then cd processor${c} if [ -d ./100 ]; then # Control will enter here if $DIRECTORY exists and delete it if so. rm -r 100 fi cd .. fi done if [ -f ./log.simpleFoam ]; then # Control will enter here if $FILE exists and delete it if so. rm log.simpleFoam fi cd .. done # Run cases for i in 2 4; do echo "Run for ${i}..." cd run_$i if [ $i -eq 1 ] then simpleFoam > log.simpleFoam 2>&1 else mpirun -np ${i} simpleFoam -parallel > log.simpleFoam 2>&1 fi cd .. done # Extract times echo "# cores Wall time (s):" echo "------------------------" for i in 2 4; do echo $i `grep Execution run_${i}/log.simpleFoam | tail -n 1 | cut -d " " -f 3` done done |
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