From f20eab9cdc26ffbacb32e5942e2969058e50581a Mon Sep 17 00:00:00 2001
From: Sylvain Joubert <joubert.sy@gmail.com>
Date: Wed, 27 Feb 2019 12:47:07 +0100
Subject: ProcessorCount: Return the container CPU count instead of the host
count
On Linux containers (tested with LXC and Docker) getconf returns the
host CPU count.
Use nproc with a higher priority if available to get the container's
allocated CPUs instead of the non-accessible host count.
---
Modules/ProcessorCount.cmake | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/Modules/ProcessorCount.cmake b/Modules/ProcessorCount.cmake
index e4b4e53..8c25256 100644
--- a/Modules/ProcessorCount.cmake
+++ b/Modules/ProcessorCount.cmake
@@ -70,6 +70,20 @@ function(ProcessorCount var)
endif()
if(NOT count)
+ # Linux (systems with nproc):
+ # Prefer nproc to getconf if available as getconf may return the host CPU count in Linux containers
+ find_program(ProcessorCount_cmd_nproc nproc)
+ mark_as_advanced(ProcessorCount_cmd_nproc)
+ if(ProcessorCount_cmd_nproc)
+ execute_process(COMMAND ${ProcessorCount_cmd_nproc}
+ ERROR_QUIET
+ OUTPUT_STRIP_TRAILING_WHITESPACE
+ OUTPUT_VARIABLE count)
+ #message("ProcessorCount: trying nproc '${ProcessorCount_cmd_nproc}'")
+ endif()
+ endif()
+
+ if(NOT count)
# Linux (systems with getconf):
find_program(ProcessorCount_cmd_getconf getconf)
mark_as_advanced(ProcessorCount_cmd_getconf)
--
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