From c2b2512be7d90d56afe55d8038d06749ab122813 Mon Sep 17 00:00:00 2001
From: Moe Jette <jette1@llnl.gov>
Date: Mon, 2 Dec 2002 18:03:00 +0000
Subject: [PATCH] Return behaviour to block distribution by default iff the
number of tasks exceeds the number of nodes and document this behaviour.
---
doc/man/man1/srun.1 | 6 ++++--
src/srun/opt.c | 8 ++++++--
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/doc/man/man1/srun.1 b/doc/man/man1/srun.1
index 2989976d577..4ac42b02a87 100644
--- a/doc/man/man1/srun.1
+++ b/doc/man/man1/srun.1
@@ -97,12 +97,14 @@ Specify an alternate distribution method for remote processes.
.TP
.B block
The block method of distribution will allocate processes in-order to
-the cpus on a node.
+the cpus on a node. This is the default behavior if the number of tasks
+exceeds the number of nodes requested.
.TP
.B cyclic
The cyclic method distributes processes in a round-robin fashion across
the allocated nodes. That is, process 1 will be allocated to the first
-node, process 2 to the second, and so on. This is the default behavior.
+node, process 2 to the second, and so on. This is the default behavior
+if the number of tasks is no larger than the number of nodes requested.
.RE
.TP
\fB\-J\fR, \fB\-\-job\-name\fR=\fIjobname\fR
diff --git a/src/srun/opt.c b/src/srun/opt.c
index 6411a1e4a2a..167c1e863a5 100644
--- a/src/srun/opt.c
+++ b/src/srun/opt.c
@@ -880,8 +880,12 @@ _opt_verify(poptContext optctx)
verified = false;
}
- if (opt.distribution == SRUN_DIST_UNKNOWN)
- opt.distribution = SRUN_DIST_CYCLIC;
+ if (opt.distribution == SRUN_DIST_UNKNOWN) {
+ if (opt.nprocs <= opt.nodes)
+ opt.distribution = SRUN_DIST_CYCLIC;
+ else
+ opt.distribution = SRUN_DIST_BLOCK;
+ }
if (opt.mincpus < opt.cpus_per_task)
opt.mincpus = opt.cpus_per_task;
--
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