yade-users team mailing list archive

["gael combe.yade" <gael.combe.yade@xxxxxxxxx>]

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
cache
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
henriette.
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
results)
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


Gael







>
> best regards
> --
> Janek Kozicki                                                         |
>
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