Further performance optimization

2026-09-30 15:48:30 +02:00
parent 65ce1b414e
commit 3170d1c6d9
7 changed files with 154 additions and 13 deletions
@@ -92,7 +92,7 @@ func (r *embedRenderer) render(w util.BufWriter, source []byte, node ast.Node, e
 		w.WriteString(strconv.Itoa(embedThumbW))
 		w.WriteString(`" alt="`)
 		w.Write(util.EscapeHTML([]byte(name)))
-		w.WriteString(`"></a>`)
+		w.WriteString(`" loading="lazy"></a>`)
 		if captioned {
 			w.WriteString(`<figcaption>`)
 		}
@@ -175,14 +175,21 @@ type reqStartKeyT struct{}

 var reqStartKey = reqStartKeyT{}

-// elapsedMS returns the milliseconds since the request entered ServeHTTP.
-func elapsedMS(r *http.Request) int64 {
+// requestStart returns when the request entered ServeHTTP, or now if unknown.
+func requestStart(r *http.Request) time.Time {
 	if start, ok := r.Context().Value(reqStartKey).(time.Time); ok {
-		return time.Since(start).Milliseconds()
+		return start
 	}
-	return 0
+	return time.Now()
 }

+// renderTimer is embedded in template data. The footer calls RenderMS while
+// the template executes, so the time includes the page's own rendering (and
+// the header's maintenance widget), not just the work before it.
+type renderTimer struct{ start time.Time }
+
+func (t renderTimer) RenderMS() int64 { return time.Since(t.start).Milliseconds() }
+
 func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	r = r.WithContext(context.WithValue(r.Context(), reqStartKey, time.Now()))

@@ -407,7 +414,7 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 	if editMode {
 		t = editTmpl
 	}
-	data.RenderMS = elapsedMS(r)
+	data.renderTimer = renderTimer{requestStart(r)}
 	if err := t.ExecuteTemplate(w, "layout", data); err != nil {
 		log.Printf("template error: %v", err)
 	}
@@ -63,7 +63,7 @@ type pageData struct {
 	SpecialContent template.HTML
 	SidebarWidget  template.HTML
 	SuppressTOC    bool
-	RenderMS       int64
+	renderTimer
 }

 // Allowed values for the listing view settings. Unknown values in the file or
@@ -12,6 +12,7 @@ import (
 	"sync"
 	"time"
 	"unicode"
+	"unicode/utf8"
 )

 // searchSectionCap bounds how many rows each results section renders. The
@@ -46,7 +47,7 @@ type searchPageData struct {
 	PageTotal    int
 	FileTotal    int
 	IndexBuiltAt time.Time
-	RenderMS     int64
+	renderTimer
 }

 // indexEntry is the shared scoreable core of both folder and file index
@@ -132,7 +133,7 @@ func (h *handler) handleSearch(w http.ResponseWriter, r *http.Request) {
 		IndexBuiltAt: builtAt,
 	}
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
-	data.RenderMS = elapsedMS(r)
+	data.renderTimer = renderTimer{requestStart(r)}
 	if err := searchTmpl.ExecuteTemplate(w, "layout", data); err != nil {
 		log.Printf("search template error: %v", err)
 	}
@@ -278,7 +279,7 @@ func scoreName(nameLower string, nameTokens []string, qLower string, qTokens []s
 				if best < 20 {
 					best = 20
 				}
-			case fuzzy && levenshtein(w, qt) <= 2:
+			case fuzzy && withinTwoEdits(w, qt):
 				if best < 5 {
 					best = 5
 				}
@@ -575,6 +576,17 @@ func tokenize(s string) []string {
 	return tokens
 }

+// withinTwoEdits reports whether a and b are at most 2 edits apart. Lengths
+// differing by more than 2 rule that out without running levenshtein, which
+// skips nearly every word pair in the per-query scoring loop.
+func withinTwoEdits(a, b string) bool {
+	d := utf8.RuneCountInString(a) - utf8.RuneCountInString(b)
+	if d < -2 || d > 2 {
+		return false
+	}
+	return levenshtein(a, b) <= 2
+}
+
 // levenshtein returns the edit distance between a and b. Operates on runes so
 // multi-byte characters count as one edit.
 func levenshtein(a, b string) int {
@@ -1,6 +1,8 @@
 package main

 import (
+	"bytes"
+	"compress/gzip"
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"
@@ -8,6 +10,7 @@ import (
 	"io/fs"
 	"net/http"
 	"strings"
+	"time"
 )

 // assetVersions maps each embedded asset (path relative to assets/, e.g.
@@ -34,6 +37,45 @@ func hashAssets() map[string]string {
 	return versions
 }

+// assetGzip holds a gzip copy of every embedded asset that compresses well,
+// keyed like assetVersions. Built once at startup so serving compressed costs
+// no CPU per request; already-compressed files (fonts) are left out.
+var assetGzip = gzipAssets()
+
+func gzipAssets() map[string][]byte {
+	out := map[string][]byte{}
+	_ = fs.WalkDir(assets, "assets", func(p string, d fs.DirEntry, err error) error {
+		if err != nil || d.IsDir() {
+			return err
+		}
+		b, err := assets.ReadFile(p)
+		if err != nil {
+			return err
+		}
+		var buf bytes.Buffer
+		zw, _ := gzip.NewWriterLevel(&buf, gzip.BestCompression)
+		zw.Write(b)
+		zw.Close()
+		// Not worth a Content-Encoding round trip unless it saves ≥10%.
+		if buf.Len() < len(b)*9/10 {
+			out[strings.TrimPrefix(p, "assets/")] = buf.Bytes()
+		}
+		return nil
+	})
+	return out
+}
+
+// acceptsGzip reports whether the client accepts a gzip response body.
+func acceptsGzip(r *http.Request) bool {
+	for _, enc := range strings.Split(r.Header.Get("Accept-Encoding"), ",") {
+		enc, q, _ := strings.Cut(strings.TrimSpace(enc), ";")
+		if strings.TrimSpace(enc) == "gzip" && strings.ReplaceAll(q, " ", "") != "q=0" {
+			return true
+		}
+	}
+	return false
+}
+
 // assetURL is the "asset" template func: {{asset "style.css"}} renders
 // /_/style.css?v=<hash>. An unknown name fails the template so a typo or a
 // removed file surfaces as a render error instead of a silent 404.
@@ -57,19 +99,37 @@ var assetFuncs = template.FuncMap{"asset": assetURL}
 //     change);
 //   - anything else (unversioned or stale ?v=, e.g. icons from CSS) gets the
 //     content hash as ETag and revalidates, answered with 304 when unchanged.
+//
+// Assets with a precompressed copy (see assetGzip) are sent gzipped to
+// clients that accept it; the gzip variant gets its own ETag.
 func serveStatic() http.Handler {
 	staticFS, _ := fs.Sub(assets, "assets")
 	static := http.StripPrefix("/_/", http.FileServer(http.FS(staticFS)))
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		name := strings.TrimPrefix(r.URL.Path, "/_/")
 		v, ok := assetVersions[name]
+		gz, hasGz := assetGzip[name]
+		useGz := hasGz && acceptsGzip(r)
+		if hasGz {
+			w.Header().Set("Vary", "Accept-Encoding")
+		}
 		switch {
 		case ok && r.URL.Query().Get("v") == v, strings.HasPrefix(name, "fonts/"):
 			w.Header().Set("Cache-Control", "public, max-age=31536000, immutable")
 		case ok:
 			w.Header().Set("Cache-Control", "no-cache")
+			if useGz {
+				w.Header().Set("ETag", `"`+v+`-gz"`)
+			} else {
 				w.Header().Set("ETag", `"`+v+`"`)
 			}
+		}
+		if useGz {
+			w.Header().Set("Content-Encoding", "gzip")
+			// ServeContent derives Content-Type from the name's extension.
+			http.ServeContent(w, r, name, time.Time{}, bytes.NewReader(gz))
+			return
+		}
 		static.ServeHTTP(w, r)
 	})
 }
@@ -1,10 +1,14 @@
 package main

 import (
+	"bytes"
+	"compress/gzip"
+	"io"
 	"io/fs"
 	"net/http"
 	"net/http/httptest"
 	"regexp"
+	"strings"
 	"testing"
 )

@@ -56,3 +60,52 @@ func TestServeStaticCaching(t *testing.T) {
 		t.Errorf("font: %q", w.Header().Get("Cache-Control"))
 	}
 }
+
+func TestServeStaticGzip(t *testing.T) {
+	h := serveStatic()
+	get := func(url, acceptEncoding, ifNoneMatch string) *httptest.ResponseRecorder {
+		r := httptest.NewRequest(http.MethodGet, url, nil)
+		if acceptEncoding != "" {
+			r.Header.Set("Accept-Encoding", acceptEncoding)
+		}
+		if ifNoneMatch != "" {
+			r.Header.Set("If-None-Match", ifNoneMatch)
+		}
+		w := httptest.NewRecorder()
+		h.ServeHTTP(w, r)
+		return w
+	}
+	want, _ := assets.ReadFile("assets/style.css")
+
+	w := get("/_/style.css", "gzip, deflate, br", "")
+	if w.Code != 200 || w.Header().Get("Content-Encoding") != "gzip" || w.Header().Get("Vary") != "Accept-Encoding" {
+		t.Fatalf("gzip: %d %q %q", w.Code, w.Header().Get("Content-Encoding"), w.Header().Get("Vary"))
+	}
+	if ct := w.Header().Get("Content-Type"); !strings.HasPrefix(ct, "text/css") {
+		t.Errorf("content-type: %q", ct)
+	}
+	zr, err := gzip.NewReader(w.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, _ := io.ReadAll(zr)
+	if !bytes.Equal(got, want) {
+		t.Errorf("gzip body does not decompress to style.css")
+	}
+
+	etag := w.Header().Get("ETag")
+	if w := get("/_/style.css", "gzip", etag); w.Code != http.StatusNotModified {
+		t.Errorf("gzip revalidate: got %d, want 304", w.Code)
+	}
+
+	for _, ae := range []string{"", "identity", "gzip;q=0"} {
+		w := get("/_/style.css", ae, "")
+		if w.Header().Get("Content-Encoding") != "" || !bytes.Equal(w.Body.Bytes(), want) {
+			t.Errorf("Accept-Encoding %q: got encoding %q", ae, w.Header().Get("Content-Encoding"))
+		}
+	}
+
+	if w := get("/_/fonts/IosevkaSlab.woff2", "gzip", ""); w.Header().Get("Content-Encoding") != "" {
+		t.Errorf("font should not be re-compressed")
+	}
+}
@@ -12,6 +12,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync"
@@ -50,6 +51,11 @@ var (

 	digestCache   = map[string]digestEntry{}
 	digestCacheMu sync.Mutex
+
+	// thumbGenSlots bounds concurrent thumbnail generation. A grid of uncached
+	// photos otherwise decodes one full-size image per browser connection at
+	// once, which on the NAS means memory pressure and CPU thrash.
+	thumbGenSlots = make(chan struct{}, runtime.NumCPU())
 )

 // digestEntry remembers the digest of a source file so repeated requests do
@@ -179,7 +185,10 @@ func (h *handler) serveThumbnail(w http.ResponseWriter, r *http.Request, srcFS s
 		return
 	}

-	if err := generateThumb(cacheFS, write); err != nil {
+	thumbGenSlots <- struct{}{}
+	err = generateThumb(cacheFS, write)
+	<-thumbGenSlots
+	if err != nil {
 		log.Printf("thumb %s: %v", rel, err)
 		http.Error(w, "thumbnail failed", http.StatusInternalServerError)
 		return