BGQ
| Blue Gene/Q (BGQ) | |
|---|---|
| Installed | August 2012 |
| Operating System | RH6.3, CNK (Linux) |
| Number of Nodes | 2048(32,768 cores), 512 (8,192 cores) |
| Interconnect | 5D Torus (jobs), QDR Infiniband (I/O) |
| Ram/Node | 16 Gb |
| Cores/Node | 16 (64 threads) |
| Login/Devel Node | bgq01,bgq02 |
| Vendor Compilers | bgxlc, bgxlf |
| Queue Submission | Loadleveler |
Specifications
BGQ is an extremely powerful and energy efficient 3rd generation IBM Supercomputer built around a system on a chip compute node that has a 16core 1.6GHz Power based CPU and 16Gb of Ram and runs a very lightweight Linux OS called CNK. The nodes are bundled in groups of 32 and then 16 of these groups make up a midplane with 2 midplanes per rack. The compute nodes are all connected togther using a custom 5D interconnect. Each midplane has 8 Power7 I/O nodes that run a full Redhat Linux OS that manages the compute nodes and mounts the GPFS filesystem.
Jobs
BGQ job size is typically determined by midplanes (512 nodes or 8192 cores), however sub-blocks can be used to further subdivide midplanes with a minimum of one IO node per block. In SciNet's configuration (with 8 I/O nodes per midplane) this allows 64 nodes (1024 cores) to be the smallest job size.
*** WAT2Q SPECIFIC ****
Compile
/bgsys/drivers/V1R1M1/ppc64/comm/xl/bin/mpich2version /bgsys/drivers/V1R1M1/ppc64/comm/xl/bin/mpixlc /bgsys/drivers/V1R1M1/ppc64/comm/xl/bin/mpixf90
Run a Job =
When not using loadleveler there is a direct launch program called runjob on BGQ that acts a lot like mpirun/mpiexec. The "block" argument is the predifined group of nodes that are already booted. See the next section on how to create these blocks manually.
runjob --block R00-M0-N03-32 --ranks-per-node=16 --np 512 --cwd=/gpfs/DDNgpfs3/xsnorthrup/osu_bgq --exe=/gpfs/DDNgpfs3/xsnorthrup/osu_bgq/osu_mbw_mr
To see running jobs and the status of available blocks use:
list_jobs list_blocks
Setup blocks
To reconfigure the BGQ nodes use the bg_console
bg_console
There are various options to create block types (section 3.2 in the BGQ admin manual), but the smallest is created using the following command:
gen_small_block <blockid> <midplane> <cnodes> <nodeboard> gen_small_block R00-M0-N03-32 R00-M0 32 N03
The block then needs to be booted using:
allocate R00-M0-N03-32
If those resources are already booted into another block, that block must be freed before the new block can be allocated.
select_block R00-M0-N03 free_block
There are many other functions in bg_console:
help all
I/O
GPFS