Use half of available CPUs

Summary: During intensive builds using all available cores tends to crash the machine. Cutting default number of jobs by half prevents that.

Reviewed By: wez

Differential Revision: D25027757

fbshipit-source-id: 5ea6c77fe4363b9ee09e50de1a5cc33281872e1d

build/fbcode_builder/getdeps/builder.py

@@ -288,9 +288,7 @@ def get_jobs_argument(num_jobs_arg: int) -> str:
         return "-j" + str(num_jobs_arg)
 
     import multiprocessing
-    num_jobs = multiprocessing.cpu_count()
-    if sys.platform == "win32":
-        num_jobs //= 2
+    num_jobs = multiprocessing.cpu_count() // 2
     return "-j" + str(num_jobs)
 
 

build/fbcode_builder/getdeps/buildopts.py

@@ -73,15 +73,7 @@ class BuildOptions(object):
         if not num_jobs:
             import multiprocessing
 
-            num_jobs = multiprocessing.cpu_count()
-            if is_windows():
-                # On Windows the cpu count tends to be the HT count.
-                # Running with that level of concurrency tends to
-                # swamp the system and make hard to perform other
-                # light work.  Let's halve the number of cores here
-                # to win that back. The user can still specify a
-                # larger number if desired.
-                num_jobs = int(num_jobs / 2)
+            num_jobs = multiprocessing.cpu_count() // 2
 
         if not install_dir:
             install_dir = os.path.join(scratch_dir, "installed")