Hi Frank, sorry, my first response was not very specific for your situation!
I studied your list and graphs and would just like to point out that in "2.1 Testing Filesystem Performance" you may be severely overcommitting the CPU resources, if this was for one machine only with 16 (=8+8) cores. (but maybe your were really only interested in filesystem performance; we are generally happy with NFSv4 but haven't tried anything else)
If testing with one machine, I'd try for XDS JOBS PROCESSORS 1 16 2 8 4 4 8 2 16 1 and then - if "4 4" was best, for example 5 4 6 4We use several 48-core AMD machines (4*12-core 6176SE 2.3GHz CPUs), and we are happy with them for general work. We also use Intel (2*6-core X5670 2.93GHz Xeon, plus Hyperthreading) machines, which give a higher single-CPU performance, but of course 48 cores are nice in some situations (for XDS, e.g. 6 to 8 JOBS of 8 PROCESSORS each). OTOH more machines may mean more rack space, and more administration.
HTH, Kay On 04/19/2011 02:06 PM, Frank Murphy wrote:
Dear All, Here at NE-CAT, we make extensive use of XDS in a parallel environment. We are looking to purchase some new hardware, so I am soliciting your opinions. Our current cluster is made up of 16 nodes, each with 2 processors that have four cores, running at 2.2 GHz (I believe). We run with hyperthreading on, so 8 physical and 16 virtual cores per node. Our benchmarking with XDS (see https://rapd.nec.aps.anl.gov/wiki/RAPD_NecatStats for an example) shows a diminishing return on increasing the MAXIMUM_NUMBER_OF_PROCESSORS beyond the number of physical cores, and we are wondering if this is due to the test, the processor, the RAM, or XDS. In short, will going to 2 six core processors speed up processing using up to 12 for MAXIMUM_NUMBER_OF_PROCESSORS? Please do not feel the need to constrain the discussion to XDS, as we use our cluster for pretty much all the common crystallographic tasks. Thanks in advance, Frank Murphy Beamline Scientist, NE-CAT
-- Kay Diederichs http://strucbio.biologie.uni-konstanz.de email: kay.diederi...@uni-konstanz.de Tel +49 7531 88 4049 Fax 3183 Fachbereich Biologie, Universität Konstanz, Box M647, D-78457 Konstanz This e-mail is digitally signed. If your e-mail client does not have the necessary capabilities, just ignore the attached signature "smime.p7s".
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