Accurately get hardware cpu count in Vagrantfile.

In Vagrantfile replace hack that assumed hyper threading was enabled on the host and divided ncpu by 2 with methods of getting the actual hardware core count.
nikhiljindal · May 9, 2015 · 19224de · 19224de
1 parent 738f403
commit 19224de
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/Vagrantfile b/Vagrantfile
@@ -70,14 +70,16 @@ $kube_provider_boxes = {
   }
 }
 
-# This stuff is cargo-culted from http://www.stefanwrobel.com/how-to-make-vagrant-performance-not-suck
-# Give access to half of all cpu cores on the host. We divide by 2 as we assume
-# that users are running with hyperthreads.
+# Give access to all physical cpu cores
+# Previously cargo-culted from here:
+# http://www.stefanwrobel.com/how-to-make-vagrant-performance-not-suck
+# Rewritten to actually determine the number of hardware cores instead of assuming
+# that the host has hyperthreading enabled.
 host = RbConfig::CONFIG['host_os']
 if host =~ /darwin/
-  $vm_cpus = (`sysctl -n hw.ncpu`.to_i/2.0).ceil
+  $vm_cpus = `sysctl -n hw.physicalcpu`.to_i
 elsif host =~ /linux/
-  $vm_cpus = (`nproc`.to_i/2.0).ceil
+  $vm_cpus = `cat /proc/cpuinfo | grep 'core id' | wc -l`.to_i
 else # sorry Windows folks, I can't help you
   $vm_cpus = 2
 end