Don't use aggregated GC metric for build reports

build-common/src/org/jetbrains/kotlin/build/report/metrics/GcMetrics.kt

@@ -12,7 +12,10 @@ class GcMetrics : Serializable {
 
     private val myGcMetrics = HashMap<String, GcMetric>()
     fun addAll(gcMetrics: GcMetrics) {
-        myGcMetrics.putAll(gcMetrics.myGcMetrics)
+        gcMetrics.myGcMetrics.forEach { (key, value) ->
+            val gcMetric = myGcMetrics[key]
+            myGcMetrics[key] = gcMetric?.let { gcMetric + value } ?: value
+        }
     }
 
     fun add(metric: String, value: GcMetric) {
@@ -22,6 +25,8 @@ class GcMetrics : Serializable {
     fun asGcCountMap(): Map<String, Long> = myGcMetrics.mapValues { it.value.count }
     fun asGcTimeMap(): Map<String, Long> = myGcMetrics.mapValues { it.value.time }
     fun asMap(): Map<String, GcMetric> = myGcMetrics
+
+    fun isEmpty() = myGcMetrics.isEmpty()
 }
 data class GcMetric(
     val time: Long,
@@ -30,4 +35,8 @@ data class GcMetric(
     operator fun minus(increment: GcMetric): GcMetric {
         return GcMetric(time - increment.time, count - increment.count)
     }
+
+    operator fun plus(increment: GcMetric?): GcMetric {
+        return GcMetric(time + (increment?.time ?: 0), count + (increment?.count ?: 0))
+    }
 }

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/report/PlainTextBuildReportWriter.kt

@@ -52,7 +52,7 @@ internal class PlainTextBuildReportWriter(
         // TODO: If it is confusing, consider renaming "tasks" to "build operations" in this class.
         printBuildInfo(build)
         if (printMetrics) {
-            printMetrics(build.aggregatedMetrics, newLineBetweenSections = true)
+            printMetrics(build.aggregatedMetrics, aggregatedMetric = true)
             p.println()
         }
         printTaskOverview(build)
@@ -77,18 +77,20 @@ internal class PlainTextBuildReportWriter(
         }
     }
 
-    private fun printMetrics(buildMetrics: BuildMetrics, newLineBetweenSections: Boolean = false) {
+    private fun printMetrics(buildMetrics: BuildMetrics, aggregatedMetric: Boolean = false) {
         printBuildTimes(buildMetrics.buildTimes)
-        if (newLineBetweenSections) p.println()
+        if (aggregatedMetric) p.println()
 
         printBuildPerformanceMetrics(buildMetrics.buildPerformanceMetrics)
-        if (newLineBetweenSections) p.println()
+        if (aggregatedMetric) p.println()
 
         printBuildAttributes(buildMetrics.buildAttributes)
-        if (newLineBetweenSections) p.println()
 
+        //TODO: KT-57310 Implement build GC metric in
+        if (!aggregatedMetric) {
             printGcMetrics(buildMetrics.gcMetrics)
         }
+    }
 
     private fun printBuildTimes(buildTimes: BuildTimes) {
         val buildTimesMs = buildTimes.asMapMs()
@@ -173,7 +175,7 @@ internal class PlainTextBuildReportWriter(
                 p.println("${gcMetric.key}:")
                 p.withIndent {
                     p.println("GC count: ${gcMetric.value.count}")
-                    p.println("GC time: ${gcMetric.value.time}")
+                    p.println("GC time: ${formatTime(gcMetric.value.time)}")
                 }
             }
         }