Description

Neocortex is a highly innovative advanced computing system ideal for foundation and large language models. Neocortex, which captures promising specialized innovative hardware technologies, is designed to vastly accelerate large deep learning (DL) models and high- performance computing (HPC) research in pursuit of science, discovery, and societal good.

Neocortex CS provides access to a Cerebras Wafer-Scale Cluster powered by a CS-3 system. The CS-3 system features a Cerebras WSE-3 (Wafer Scale Engine 3), the largest chip ever built, with 900,000 Sparse Linear Algebra Compute cores, 44 GB SRAM on-chip memory, 24 PB/s aggregate memory bandwidth and 245 Pb/s interconnect bandwidth. Hosted in the Cerebras Developer Cloud, the Neocortex cluster includes a MemoryX external memory node which provides virtually unlimited model weight capacity as well as a SwarmX Fabric interconnect that enables highly efficient scaling to additional CS3 units which can be added on demand. NLP, Vision and Multimodal deep learning models optimized to run on Cerebras hardware are available, supported by data processors, utilities, layers and losses. An LLM assistant can provide information and execute commands. The Cerebras SDK enables the development of new DL and HPC applications.

Resource ID
2055
Global Resource ID
neocortex.psc.access-ci.org
Resource Type
Compute
Latest Status
production
Latest Status Begin
Project Affiliation
ACCESS
Organization Name
Pittsburgh Supercomputing Center
RP Description

PSC Neocortex CS is an AI-focused computing environment for deep learning and data-driven research using Cerebras wafer-scale systems, PSC workflow tools, and Bridges-2-backed storage. It is intended for workloads that benefit from specialized AI acceleration rather than conventional GPU-only training.

For CS-2 workflows, users connect through SSH or Open OnDemand, prepare code and data on the SDF/Superdome Flex host environment, and run validation, compilation, training, or evaluation through the Cerebras software stack. The CS-2 system includes two Cerebras CS-2 accelerators federated with Bridges-2 for persistent data management and supporting compute workflows.

PSC also documents CS-3 access separately. Users with a CS-3 allocation should follow the current PSC Neocortex CS-3 documentation for the appropriate login, job, and storage workflow.

MFA Required
Off
File Transfer Text

Neocortex provides data transfer nodes for moving data into and out of the Neocortex environment. PSC documents rsync as the preferred method, with scp not recommended and sftp also supported.

Use data.neocortex.psc.edu for command-line transfers to project or shared storage, such as locations under /ocean/projects/<GRANT_ID>/. See the Neocortex Data Management and Storage documentation for current examples.

File Transfer Methods
Transfer Method
Rsync
Data Transfer Node / Globus Collection
data.neocortex.psc.edu
Transfer Method
SCP
Data Transfer Node / Globus Collection
data.neocortex.psc.edu
Transfer Method
SFTP
Data Transfer Node / Globus Collection
data.neocortex.psc.edu
Storage Text

Neocortex uses PSC's persistent /jet and /ocean filesystems for personal and project data. Use $HOME for small personal files, $PROJECT for project data, and $PROJECT/../shared for files shared with project members.

The SDFlex host used by Neocortex CS workflows also provides node-local storage at /local1 through /local4. These locations are temporary and visible only from the SDFlex compute nodes. Use $LOCAL inside jobs and copy important results back to persistent project storage before the job ends.

If you belong to multiple PSC projects, run newgrp <GROUP_ID> before using $PROJECT for the intended allocation.

Jobs Information

Neocortex CS-2 uses Slurm for interactive and batch workloads. The SDFlex host nodes support data preparation, validation, compilation, training, and evaluation workflows for the Cerebras CS-2 systems.

Before submitting a job, identify the appropriate PSC project and select its Unix group:

projects groups newgrp GRANT_ID

Common Slurm commands include:

squeue -u $USER # Show your queued and running jobs squeue -j JOB_ID # Show one job scancel JOB_ID # Cancel a job scontrol show job JOB_ID # Display detailed job information

Start an interactive job on either available SDF node with:

interact

To request a specific SDF node, use:

srun --nodelist=sdf-1 --pty bash -i

For CPU-based validation or compilation, request an SDF host node and start the PSC-provided Cerebras container:

srun --pty \ --cpus-per-task=28 \ --kill-on-bad-exit \ singularity shell \ --cleanenv \ --bind /local1/cerebras/data,/local2/cerebras/data,/local3/cerebras/data,/local4/cerebras/data,$PROJECT \ /ocean/neocortex/cerebras/cbcore_latest.sif

A CS-2 training or evaluation job must request a Cerebras accelerator. A minimal batch-script header is:

#!/usr/bin/bash #SBATCH --job-name=cs2-job #SBATCH --account=GRANT_ID #SBATCH --time=04:00:00 #SBATCH --gres=cs:cerebras:1 #SBATCH --ntasks=7 #SBATCH --cpus-per-task=14 #SBATCH --output=%x-%j.out newgrp GRANT_ID # Add the Cerebras container and application commands here.

Submit and monitor the script with:

sbatch job.sbatch squeue -u $USER

The documented default wall time for normal interactive and batch jobs is four hours, and the maximum wall time is 48 hours. Reservations may use a different duration when approved by the Neocortex team.

See the instructions for running interactive and batch CS-2 jobs, the complete Neocortex compilation and batch-script examples, and the Neocortex reservation and wall-time instructions.

Storage Filesystems
Directory
Ocean
File System Path
/ocean
Quota (Deprecated)
Allocation Based
Notes
Shared storage
Directory
Project
File System Path
/ocean/projects/<allocation>/<user>
Quota (Deprecated)
Allocation Based
Notes
Project storage
Directory
Jet
File System Path
/jet/home/PSC_USERNAME
Quota (Deprecated)
25 GB cap
Notes
Home; max quota may block login
Directory
Local
File System Path
/local{1..4}
Quota (Deprecated)
Job Only
Purge Policy
Cleared after job
Backup Policy
Not backed up
Notes
Temporary high-speed job I/O
Queue Specifications
Queue Name
sdf
Purpose
SDFlex host nodes for CS-2 validation, compilation, training, and evaluation workflows
CPU Type
Intel Xeon Platinum 8280L
RAM (Deprecated)
24 TiB RAM and 32 × 6.4 TB NVMe SSDs across the HPE Superdome Flex system