Oskar Enoksson wrote:
> Christopher Samuel wrote:
>> Subject: Re: [OMPI devel] Very poor performance with btl sm on twin
>> nehalem servers with Mellanox ConnectX installed
>> To: devel_at_[hidden]
>> Content-Type: text/plain; charset="iso-8859-1"
>> On 13/05/10 20:56, Oskar Enoksson wrote:
>>> The problem is that I get very bad performance unless I
>>> explicitly exclude the "sm" btl and I can't figure out why.
>> Recently someone reported issues which were traced back to
>> the fact that the files that sm uses for mmap() were in a
>> /tmp which was NFS mounted; changing the location where their
>> files were kept to another directory with the orte_tmpdir_base
>> MCA parameter fixed that issue for them.
>> Could it be similar for yourself ?
> That was exactly right, as you guessed these are diskless nodes that
> mounts the root filesystem over NFS.
> Setting orte_tmpdir_base to /dev/shm and btl_sm_num_fifos=9 and then
> running mpi_stress on eight cores measures speeds of 1650MB/s for both
> 1MB messages and 1600MB/s for 10kB messages.
> devel mailing list
Sounds like a new FAQ entry is warranted.
Paul H. Hargrove PHHargrove_at_[hidden]
Future Technologies Group
HPC Research Department Tel: +1-510-495-2352
Lawrence Berkeley National Laboratory Fax: +1-510-486-6900