cmake: use nproc if _num_cores is zero

The previous workaround set _num_cores to 1 if cmake thought NUMBER_OF_LOGICAL_CORES was zero. That worked fine, but it'd be much better to take advantage of all possible cores. This version runs `nproc` which seems to work just fine under qemu-aarch64 and gives us the actual number of CPUs. Fixes: b666926 Signed-off-by: Tim Serong <[email protected]>
tserong · Nov 24, 2023 · d20b0f7 · d20b0f7
1 parent 70d8c11
commit d20b0f7
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/cmake/modules/LimitJobs.cmake b/cmake/modules/LimitJobs.cmake
@@ -5,7 +5,11 @@ cmake_host_system_information(RESULT _num_cores QUERY NUMBER_OF_LOGICAL_CORES)
 # This will never be zero on a real system, but it can be if you're doing
 # weird things like trying to cross-compile using qemu emulation.
 if(_num_cores EQUAL 0)
-  set(_num_cores 1)
+  execute_process(
+    COMMAND "nproc"
+    OUTPUT_VARIABLE _num_cores
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(WARNING "Unable to query NUMBER_OF_LOGICAL_CORES, defaulting to nproc (${_num_cores})")
 endif()
 cmake_host_system_information(RESULT _total_mem QUERY TOTAL_PHYSICAL_MEMORY)