XCI - Marvell Thunder X2
Cray XC50 cabinet, codenamed XCI, containing 20’992 ARM cores. Available since November 2018, expanded September 2020.
Marvell ThunderX2 ARM v8.1
16nm FinFET CPU @ 2.1GHz (permanent turbo to 2.5GHz)
4-way simultaneous multi-threading
128-bit SIMD “NEON”
32KB L1 instruction & data cache, 256KB L2 per core, 32MB distributed L3 cache
8 DDR4 DIMMs @ 2666MHz * 160 nodes of 256GB, 169 nodes of 512GB
Cray Aries interconnect in dragonfly topology operating at 14Gbps~
Cray Linux Environment 7 (Suse SLES 15)
Cray Programming Environment
Queues
Work is submitted via the arm
queue.
There is also an arm-dev
queue for running interactive development jobs up to three hours in duration. To specify an interactive job add the -I
flag to your qsub
command.
To target the larger memory nodes, add the following to your job script:
#PBS -l mem=500GB
Caveats
The default python version on login nodes is a system-bundled version, be sure to load a version of cray-python
.
Known errors
Some Cray compilers will emit this error message:
No supported cpu target is set, CRAY_CPU_TARGET=aarch64 will be used.
Load a valid targeting module or set CRAY_CPU_TARGET
To silence this message and to ensure the correct CPU optimisations are applied, run the following before using the compiler:
module load craype-arm-thunderx2