From 2f1a0f6f0eabe090d3ea95c4f508ef72454369a2 Mon Sep 17 00:00:00 2001
From: Aaron Carlisle <carlisle.b3d@gmail.com>
Date: Wed, 7 Oct 2020 10:25:06 -0400
Subject: [PATCH] PyDoc: Multithread sphinx-build

Compile times went from over 5min to under 2 on my laptop.
---
 GNUmakefile                      |  2 +-
 doc/python_api/sphinx_doc_gen.sh | 20 ++++++++++++++++++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/GNUmakefile b/GNUmakefile
index e4b5f3b99dc..660493b5945 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -517,7 +517,7 @@ doc_py: .FORCE
 	ASAN_OPTIONS=halt_on_error=0 \
 	$(BLENDER_BIN) --background -noaudio --factory-startup \
 		--python doc/python_api/sphinx_doc_gen.py
-	sphinx-build -b html doc/python_api/sphinx-in doc/python_api/sphinx-out
+	sphinx-build -b html -j $(NPROCS) doc/python_api/sphinx-in doc/python_api/sphinx-out
 	@echo "docs written into: '$(BLENDER_DIR)/doc/python_api/sphinx-out/index.html'"
 
 doc_doxy: .FORCE
diff --git a/doc/python_api/sphinx_doc_gen.sh b/doc/python_api/sphinx_doc_gen.sh
index be11a10d053..0dcb8ce04a8 100755
--- a/doc/python_api/sphinx_doc_gen.sh
+++ b/doc/python_api/sphinx_doc_gen.sh
@@ -27,6 +27,22 @@ else
 fi
 
 
+# -----------------------------------------------------------------------------
+# Get the number of cores for threaded build
+ifndef NPROCS
+	NPROCS:=1
+	ifeq ($(OS), Linux)
+		NPROCS:=$(shell nproc)
+	endif
+	ifeq ($(OS), NetBSD)
+		NPROCS:=$(shell getconf NPROCESSORS_ONLN)
+	endif
+	ifneq (,$(filter $(OS),Darwin FreeBSD))
+		NPROCS:=$(shell sysctl -n hw.ncpu)
+	endif
+endif
+
+
 # ----------------------------------------------------------------------------
 # Blender Version & Info
 
@@ -76,7 +92,7 @@ fi
 # Generate HTML (sphinx)
 
 if $DO_OUT_HTML ; then
-  sphinx-build -b html $SPHINX_WORKDIR/sphinx-in $SPHINX_WORKDIR/sphinx-out
+  sphinx-build -b html -j $(NPROCS) $SPHINX_WORKDIR/sphinx-in $SPHINX_WORKDIR/sphinx-out
 
   # XXX, saves space on upload and zip, should move HTML outside
   # and zip up there, for now this is OK
@@ -103,7 +119,7 @@ fi
 # Generate PDF (sphinx/laytex)
 
 if $DO_OUT_PDF ; then
-  sphinx-build -n -b latex $SPHINX_WORKDIR/sphinx-in $SPHINX_WORKDIR/sphinx-out
+  sphinx-build -n -b latex -j $(NPROCS) $SPHINX_WORKDIR/sphinx-in $SPHINX_WORKDIR/sphinx-out
   make -C $SPHINX_WORKDIR/sphinx-out
   mv $SPHINX_WORKDIR/sphinx-out/contents.pdf \
      $SPHINX_WORKDIR/sphinx-out/blender_python_reference_$BLENDER_VERSION.pdf