From 1b2bc53bcf6dd5ef8aec44d3044560564d3a5ba8 Mon Sep 17 00:00:00 2001
From: mkdev11 <jaysmth689@gmail.com>
Date: Sat, 10 Jan 2026 15:03:57 +0200
Subject: [PATCH] fix: Improve GCMonitor warning message clarity

Add 'seconds' unit to GC time and clarify that the percentage
represents cumulative GC pause time across all collectors.

Fixes #8002
---
 main/src/main/scala/sbt/internal/GCMonitor.scala | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/main/src/main/scala/sbt/internal/GCMonitor.scala b/main/src/main/scala/sbt/internal/GCMonitor.scala
index 79b49af02..f39b8a4ff 100644
--- a/main/src/main/scala/sbt/internal/GCMonitor.scala
+++ b/main/src/main/scala/sbt/internal/GCMonitor.scala
@@ -62,8 +62,10 @@ class GCMonitor(logger: Logger) extends GCMonitorBase with AutoCloseable {
 
   override protected def emitWarning(total: Long, over: Option[Long]): Unit = {
     val totalSeconds = total / 1000.0
-    val amountMsg = over.fold(s"$totalSeconds seconds") { d =>
-      "In the last " + (d / 1000.0).ceil.toInt + f" seconds, $totalSeconds (${total.toDouble / d * 100}%.1f%%)"
+    val amountMsg = over.fold(f"$totalSeconds%.3f seconds") { d =>
+      val dSeconds = (d / 1000.0).ceil.toInt
+      val percentage = total.toDouble / d * 100
+      f"In the last $dSeconds seconds, $totalSeconds%.3f seconds ($percentage%.1f%%) of GC pause"
     }
     val msg = s"$amountMsg were spent in GC. " +
       s"[Heap: ${gbString(runtime.freeMemory())} free " +