Pinning
Last updated on 2025-09-24 | Edit this page
Estimated time: 10 minutes
Overview
Questions
- What is “pinning” of job resources?
- How can pinning improve the performance?
- How can I see, if pinning resources would help?
- What requirement hints can I give to the scheduler?
Objectives
After completing this episode, participants should be able to …
- Define the concept of “pinning” and how it can affect job performance.
- Name Slurms options for memory- and cpu- binding.
- Use hints to tell Slurm how to optimize their job allocation.
Narrative:
- We get the feeling, that hardware has a lot to offer, but the rabbit hole is deep!
- What are the “dimensions” in which we can optimize the throughput of snowman pictures per hour?
- Can we improve how the work maps to certain CPUs / Memory regions?
What we’re doing here:
- Introduce pinning and slurm hint options
- Relate to hardware effects
- Use third party performance tools to observe effects!
Stick to simple options here. Put more complex options for pinning / hints, etc. into its own episode somewhere later in the course
Pinning is an important part of job optimization, but requires some knowledge, e.g. about the hardware hierarchies in a cluster, NUMA, etc. So it should be done after we’ve introduced different performance reports and their perspective on hardware
Maybe point to JSC pinning simulator and have similar diagrams as an independent “offline” version in this course
Binding / pinning:
--mem-bind=[{quiet|verbose},]<type>-m, --distribution={*|block|cyclic|arbitrary|plane=<size>}[:{*|block|cyclic|fcyclic}[:{*|block|cyclic|fcyclic}]][,{Pack|NoPack}]-
--hint=: Hints for CPU- (compute_bound) and memory-bound (memory_bound), but alsomultithread,nomultithread -
--cpu-bind=[{quiet|verbose},]<type>(srun) - Mapping of application <-> job resources
Why what how?
B
Summary
Leading question: Pinning is very specific, but was it really limiting the performance of out application? How can I identify the biggest issue?
- C