From 06d91bdd9f96669d3663ee189d427f30c245bc99 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Wed, 6 Sep 2023 14:48:09 +0200
Subject: [PATCH] log: avoid stack lookups when not needed/used

---
 log/logger.go      |  9 ++++++---
 log/logger_test.go | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)
 create mode 100644 log/logger_test.go

diff --git a/log/logger.go b/log/logger.go
index 4e471a22da..c12c067095 100644
--- a/log/logger.go
+++ b/log/logger.go
@@ -177,19 +177,22 @@ type logger struct {
 }
 
 func (l *logger) write(msg string, lvl Lvl, ctx []interface{}, skip int) {
-	l.h.Log(&Record{
+	record := &Record{
 		Time: time.Now(),
 		Lvl:  lvl,
 		Msg:  msg,
 		Ctx:  newContext(l.ctx, ctx),
-		Call: stack.Caller(skip),
 		KeyNames: RecordKeyNames{
 			Time: timeKey,
 			Msg:  msgKey,
 			Lvl:  lvlKey,
 			Ctx:  ctxKey,
 		},
-	})
+	}
+	if locationEnabled.Load() {
+		record.Call = stack.Caller(skip)
+	}
+	l.h.Log(record)
 }
 
 func (l *logger) New(ctx ...interface{}) Logger {
diff --git a/log/logger_test.go b/log/logger_test.go
new file mode 100644
index 0000000000..b35e5493c7
--- /dev/null
+++ b/log/logger_test.go
@@ -0,0 +1,14 @@
+package log
+
+import (
+	"os"
+	"testing"
+)
+
+func BenchmarkTraceLogging(b *testing.B) {
+	Root().SetHandler(LvlFilterHandler(LvlInfo, StreamHandler(os.Stderr, TerminalFormat(true))))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Trace("a message", "v", i)
+	}
+}