From 0431fdc3554c85277e53f6d70ab02260cdcacec0 Mon Sep 17 00:00:00 2001
From: Martin Schroschk <martin.schroschk@tu-dresden.de>
Date: Thu, 2 May 2024 13:28:16 +0200
Subject: [PATCH] Review section on exclusive jobs
- Tighten desc.
- Remove "partitions"
---
.../docs/jobs_and_resources/slurm_examples.md | 48 +++++++++----------
1 file changed, 24 insertions(+), 24 deletions(-)
diff --git a/doc.zih.tu-dresden.de/docs/jobs_and_resources/slurm_examples.md b/doc.zih.tu-dresden.de/docs/jobs_and_resources/slurm_examples.md
index c28932a8d..2f103faa7 100644
--- a/doc.zih.tu-dresden.de/docs/jobs_and_resources/slurm_examples.md
+++ b/doc.zih.tu-dresden.de/docs/jobs_and_resources/slurm_examples.md
@@ -253,40 +253,40 @@ enough resources in total were specified in the header of the batch script.
## Exclusive Jobs for Benchmarking
-Jobs ZIH systems run, by default, in shared-mode, meaning that multiple jobs (from different users)
-can run at the same time on the same compute node. Sometimes, this behavior is not desired (e.g.
-for benchmarking purposes). Thus, the Slurm parameter `--exclusive` request for exclusive usage of
-resources.
-
-Setting `--exclusive` **only** makes sure that there will be **no other jobs running on your nodes**.
-It does not, however, mean that you automatically get access to all the resources which the node
-might provide without explicitly requesting them, e.g. you still have to request a GPU via the
-generic resources parameter (`gres`) to run on the partitions with GPU, or you still have to
-request all cores of a node if you need them. CPU cores can either to be used for a task
-(`--ntasks`) or for multi-threading within the same task (`--cpus-per-task`). Since those two
-options are semantically different (e.g., the former will influence how many MPI processes will be
-spawned by `srun` whereas the latter does not), Slurm cannot determine automatically which of the
-two you might want to use. Since we use cgroups for separation of jobs, your job is not allowed to
-use more resources than requested.*
-
-If you just want to use all available cores in a node, you have to specify how Slurm should organize
-them, like with `--partition=haswell --cpus-per-tasks=24` or `--partition=haswell --ntasks-per-node=24`.
+Jobs on ZIH systems run, by default, in shared-mode, meaning that multiple jobs (from different
+users) can run at the same time on the same compute node. Sometimes, this behavior is not desired
+(e.g. for benchmarking purposes). You can request for exclusive usage of resources using the Slurm
+parameter `--exclusive`.
+
+!!! note "Exclusive does not allocate all available resources"
+
+ Setting `--exclusive` **only** makes sure that there will be **no other jobs running on your
+ nodes**. It does not, however, mean that you automatically get access to all the resources
+ which the node might provide without explicitly requesting them.
+
+ E.g. you still have to request for a GPU via the generic resources parameter (`gres`) on the GPU
+ cluster. On the other hand, you also have to request all cores of a node if you need them.
+
+CPU cores can either to be used for a task (`--ntasks`) or for multi-threading within the same task
+(`--cpus-per-task`). Since those two options are semantically different (e.g., the former will
+influence how many MPI processes will be spawned by `srun` whereas the latter does not), Slurm
+cannot determine automatically which of the two you might want to use. Since we use cgroups for
+separation of jobs, your job is not allowed to use more resources than requested.
Here is a short example to ensure that a benchmark is not spoiled by other jobs, even if it doesn't
-use up all resources in the nodes:
+use up all resources of the nodes:
-!!! example "Exclusive resources"
+!!! example "Job file with exclusive resources"
```Bash
#!/bin/bash
- #SBATCH --partition=haswell
#SBATCH --nodes=2
#SBATCH --ntasks-per-node=2
#SBATCH --cpus-per-task=8
- #SBATCH --exclusive # ensure that nobody spoils my measurement on 2 x 2 x 8 cores
+ #SBATCH --exclusive # ensure that nobody spoils my measurement on 2 x 2 x 8 cores
#SBATCH --time=00:10:00
- #SBATCH --job-name=Benchmark
- #SBATCH --mail-type=end
+ #SBATCH --job-name=benchmark
+ #SBATCH --mail-type=start,end
#SBATCH --mail-user=<your.email>@tu-dresden.de
srun ./my_benchmark
--
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