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Re: Triax profiling on cluster


2009/9/23 Janek Kozicki <janek_listy@xxxxx>

> And one more thing, the head node on a cluster is AMD. Everyone uses
> it to submit jobs, the head node should never be used to run
> calculations.
> But I made a benchmark on head node during some weekend on the
> night, when nobody wasn't working.
> This head node with AMD is indeed twice faster than 8 CPU nodes
> E5440, and four times faster than 16 CPU nodes X7350 (under full
> load). Four times faster, can you imagine?
> But of course that head node is only 2 CPUs. So it cannot calculate
> that many as those 16 CPU nodes. But a single monothread job goes
> crazy fast.
> I suspect that when Gael told me that the cluster is twice faster
> than his old AMD sun workstations in his room (orioles, etc..) is
> that he was running a simulation on the AMD head node, instead of
> submitting it to a cluster. But I never had a chance to ask him.

No i did not !
On My "old sun machines", the proc is an OPTERON 280, 2.4Ghz, 2x1Mo for the
On the frontal r0calcul1 of the cluster, also called "henriette" (try a ssh
on "henriette", it is a great experience),
the proc is an OPTERON 1222, 3.0Ghz, 2x1Mo for the cache.

When my job is 360 seconds long on my " old sun", it is 300 seconds long on
Running it on one of the node of "henriette" , the time duration is \simeq
divided by two !
(i will make some new test in few days to give your some more accurate
BUT the main difference between the YADE benchmark and the benchmark with my
program is that
I test a small amount a particles (10000 in 2D), so i think that everything
was placed in the cache memory
of the proc (especially for xeon which have big cache).
There is an option with qsub which call for a node with proc with big
cache... ask remy


> best regards
> --
> Janek Kozicki                                                         |
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