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Ticket Resolution Summary Owner Reporter
#1849 fixed Error in reconfiguration : The program was unable to request more memory space annette rm024650
Description

Dear CMS helpdesk

I am trying to run a copy of the standard N96 GA6 job with a modified orography ancil (job id xmkxc). The job failed at reconfiguration with the error message in /home/n02/n02/rm024650/output/xmkxc000.xmkxc.d16092.t180656.rcf.leave :

tcmalloc: large alloc 1651075284992 bytes == (nil) lib-4205 : UNRECOVERABLE library error The program was unable to request more memory space.

I'm not sure why this is happening. In a separate run (xmkxb) with a different modified orog ancil everything worked fine. Any advice please?

regards Mike

#1857 answered Performance of Rose suite on Monsoon annette cthomas
Description

Hi all,

I am running a Rose assimilation suite on Monsoon (and ARCHER) which uses NEMO/CICE and NEMOVAR. There are three main stages which repeat each cycle: the observation operator (obsoper), NEMOVAR, and finally the incremental analysis update (IAU). The suite was primarily developed at the Met Office and was divided into different Rose tasks, which works well on Monsoon but runs into problems on ARCHER due to the significantly longer queues. In order to run the suite more efficiently on ARCHER I have converted the tasks into one monolithic job which uses the same set of processors for all three stages mentioned above instead of claiming and releasing resources each time.

I have two questions about this. Firstly, I am interested in whether it's possible to check the performance of the job on Monsoon using perftools or similar, in order to check for any places where the job could be made more efficient. I found this similar question for the UM (http://cms.ncas.ac.uk/ticket/1711) so I hope there is a similar way to do it for Rose.

Secondly I would be interested to know if any performance gain could be achieved between the IAU and obsoper stages. The IAU produces the analysis from one cycle which is then used as the background in the obsoper stage for the next cycle. At the moment the analysis is written to disk (as a netcdf file) during IAU before being read in again by the obsoper. We were wondering if keeping it in memory is possible at all, and if so, whether doing that would actually bring any benefit. In other words is reading from memory faster or slower than reading from a disk. I think at the very least there might be issues with the namelist (NEMO complains if you have both ln_asmiau and ln_bkgwri set to true, for example), but if that can be overcome then maybe it's possible… I realise this might be a tricky question to answer but if you had any advice I'd be very interested to hear it.

Thanks, Chris

#1859 fixed Getting code from Met Office repository of the UM annette simon.tett
Description

Hi,

I've got a job from a friendly person at the Met Office.. which has some code changes. Specifically:

fcm:um_br/dev/hadmn/vn8.5_volcano_decadal/src and fcm:um_br/dev/hadmn/vn8.5_volcano_decadal/src

(and I have a code change I'd like to send back to them).

How should I do this?

thanks Simon

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