Parallelizing the largest build processes (templates, pages, indexes). Seeing 300%+ improvement of total build time.

hugolib/site.go

@@ -27,6 +27,7 @@ import (
 	"io"
 	"os"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -249,7 +250,13 @@ func (s *Site) CreatePages() (err error) {
 	if len(s.Source.Files()) < 1 {
 		return fmt.Errorf("No source files found in %s", s.absContentDir())
 	}
-	for _, file := range s.Source.Files() {
+
+	var wg sync.WaitGroup
+	for _, fi := range s.Source.Files() {
+		wg.Add(1)
+		go func(file *source.File) (err error) {
+			defer wg.Done()
+
 			page, err := ReadFrom(file.Contents, file.LogicalName)
 			if err != nil {
 				return err
@@ -270,8 +277,12 @@ func (s *Site) CreatePages() (err error) {
 			if s.Config.BuildDrafts || !page.Draft {
 				s.Pages = append(s.Pages, page)
 			}
+
+			return
+		}(fi)
 	}
 
+	wg.Wait()
 	s.Pages.Sort()
 	return
 }
@@ -368,8 +379,12 @@ func (s *Site) RenderAliases() error {
 }
 
 func (s *Site) RenderPages() (err error) {
-	for _, p := range s.Pages {
+	var wg sync.WaitGroup
+	for _, page := range s.Pages {
+		wg.Add(1)
+		go func(p *Page) (err error) {
 			var layout []string
+			defer wg.Done()
 
 			if !p.IsRenderable() {
 				self := "__" + p.TargetPath()
@@ -383,17 +398,25 @@ func (s *Site) RenderPages() (err error) {
 				layout = append(layout, "_default/single.html")
 			}
 
-		err := s.render(p, p.TargetPath(), layout...)
+			return s.render(p, p.TargetPath(), layout...)
+		}(page)
+	}
+	wg.Wait()
+
 	if err != nil {
 		return err
 	}
-	}
 	return nil
 }
 
-func (s *Site) RenderIndexes() error {
+func (s *Site) RenderIndexes() (err error) {
+	var wg sync.WaitGroup
 	for singular, plural := range s.Config.Indexes {
-		for k, o := range s.Indexes[plural] {
+		for key, oo := range s.Indexes[plural] {
+			wg.Add(1)
+
+			go func(k string, o WeightedPages) (err error) {
+				defer wg.Done()
 				n := s.NewNode()
 				n.Title = strings.Title(k)
 				base := plural + "/" + k
@@ -402,7 +425,7 @@ func (s *Site) RenderIndexes() error {
 				n.Data[singular] = o
 				n.Data["Pages"] = o.Pages()
 				layout := "indexes/" + singular + ".html"
-			err := s.render(n, base+".html", layout)
+				err = s.render(n, base+".html", layout)
 				if err != nil {
 					return err
 				}
@@ -415,8 +438,11 @@ func (s *Site) RenderIndexes() error {
 						return err
 					}
 				}
+				return
+			}(key, oo)
 		}
 	}
+	wg.Wait()
 	return nil
 }
 

main.go

@@ -15,8 +15,10 @@ package main
 
 import (
 	"github.com/spf13/hugo/commands"
+	"runtime"
 )
 
 func main() {
+	runtime.GOMAXPROCS(runtime.NumCPU())
 	commands.Execute()
 }