WRF EMS Benchmark results and hardware

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meteoadriatic
Posts: 1510
Joined: Wed Aug 19, 2009 10:05 am

Re: WRF EMS Benchmark results and hardware

Post by meteoadriatic » Tue Sep 24, 2013 3:21 pm

I though it is T620.

I wasn't familiarized with those new hardware but I downloaded operation manuals. I found that:

a) You have four-channel RAM controller, but in current configuration with only two modules installed in banks per CPU, you use it in two-channel mode. It would have better memory bandwidth if you use 4 DIMMs with each CPU (total of eight modules).

b) In current configuration, it is possible that your memory controller is configured in "Advanced ECC" mode, whereas, for maximum memory bandwidth and minimum latency, you need to configure the "Optimizer Memory" mode. I guess this can be done in BIOS setup but I didn't not verified that.

You really need to check this paper:
http://i.dell.com/sites/doccontent/shar ... -guide.pdf

c) Does your memory run at 1600MHz or less? You can chech this with command "dmidecode --type 17" (as root): You will see fields with Speed: xxxx MHz.

d) Please upgrade operating system to latest release:
https://www.scientificlinux.org/documen ... upgrade.6x

theocarter2911
Posts: 61
Joined: Fri Mar 08, 2013 5:22 am

Re: WRF EMS Benchmark results and hardware

Post by theocarter2911 » Tue Sep 24, 2013 3:53 pm

Hi,

Urk - I should have read further through that document! My memory shows:
Speed: 1600 MHz
Manufacturer: 00CE04B300CE
Serial Number: 350B55FB
Asset Tag: 02124721
Part Number: M393B1K70DH0-YK0
Rank: 2
Configured Clock Speed: 1600 MHz
If I remember correctly the ECC was switched off but I will go through the BIOS and confirm tonight, and will switch on Optimizer mode if I can find that.
I will also do the upgrade tonight, am on nightshift, after my 12Z run has finished. And will spend time on thinking how I will convince my boss that I need another 4 memory modules... :-)

Thank you so much for the help and ideas, I should really have figured out that the 4 modules leave me in two-channel mode.
Theo

meteoadriatic
Posts: 1510
Joined: Wed Aug 19, 2009 10:05 am

Re: WRF EMS Benchmark results and hardware

Post by meteoadriatic » Tue Sep 24, 2013 4:02 pm

Don't turn off ECC features, just see if there is memory operating mode that can be changed to "Optimizer".

Try to find any published benchmarks for T/R620 with memory bandwith measurements in different memory configurations. It might not be worth purchasing additional memory modules. However, my speculative expectation is that you would gain around 20% improvement if you go from two to four channel RAM. You might contact Dell support and ask for those benchmarks if they can provide you with it.

theocarter2911
Posts: 61
Joined: Fri Mar 08, 2013 5:22 am

Re: WRF EMS Benchmark results and hardware

Post by theocarter2911 » Tue Sep 24, 2013 4:27 pm

I have had a look at the prices of the RAM, and may buy it myself, will be easier than going through company procurement! I am trying to speed up my runs by another 15 mins so that it will be available for the latest issuing of landing forecasts. So, between the ram, the SL upgrade and the possibility of "optimizer" mode, I may just make it! :-)
In reverse order of priority of course.

meteoadriatic
Posts: 1510
Joined: Wed Aug 19, 2009 10:05 am

Re: WRF EMS Benchmark results and hardware

Post by meteoadriatic » Tue Sep 24, 2013 4:32 pm

Be careful not to buy different modules than already installed. Mixing modules with different specification or usually even different brand is not allowed and will probably result in dropping MHz speed to minimum or refusing to work completely. Server boards are very picky with ram modules.

theocarter2911
Posts: 61
Joined: Fri Mar 08, 2013 5:22 am

Re: WRF EMS Benchmark results and hardware

Post by theocarter2911 » Tue Sep 24, 2013 4:38 pm

I agree and will make sure of that!

theocarter2911
Posts: 61
Joined: Fri Mar 08, 2013 5:22 am

Re: WRF EMS Benchmark results and hardware

Post by theocarter2911 » Wed Sep 25, 2013 2:22 am

Hi Meteoadriatic,

Looks like it is up to the ram upgrade now (two to four channel). I upgraded Scientific Linux to 6.4 and checked the BIOS settings for the current ram - which is set to "Optimized" already. Did a large nested NMM benchmark and it came in at 31 minutes, pretty close to what I had before.

Thanks for the help,
Theo

meteoadriatic
Posts: 1510
Joined: Wed Aug 19, 2009 10:05 am

Re: WRF EMS Benchmark results and hardware

Post by meteoadriatic » Wed Sep 25, 2013 5:55 am

Does your system still feel sluggish? This feeling is in graphical mode? If yes, can you shut down GUI and X server and then try to run benchmark? Maybe something eats up resources when GUI is activated.

theocarter2911
Posts: 61
Joined: Fri Mar 08, 2013 5:22 am

Re: WRF EMS Benchmark results and hardware

Post by theocarter2911 » Thu Sep 26, 2013 12:43 am

It does still feel sluggish, I have a suspicion it is because I am used to fairly good graphics cards - and on this server it is just the basic onboard graphics that is slow, but I will give bypassing X a try when next on duty tomorrow afternoon.

theocarter2911
Posts: 61
Joined: Fri Mar 08, 2013 5:22 am

Re: WRF EMS Benchmark results and hardware

Post by theocarter2911 » Sat Sep 28, 2013 3:34 am

Hi Meteoadriatic,
With no X it is only a minute and a half faster, so nothing significant there. I will do the ram next and see.
Theo

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