enhance(dev): improve mem report (#17118)

* wip

* wip

* Update report-backend-memory.yml

* Update report-backend-memory.yml

* Update .github/workflows/report-backend-memory.yml

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

4 files changed, 99 insertions, 40 deletions

diff --git a/.github/workflows/report-backend-memory.yml b/.github/workflows/report-backend-memory.yml
index 47ec652cfd..451a8cf9e6 100644
--- a/.github/workflows/report-backend-memory.yml
+++ b/.github/workflows/report-backend-memory.yml
@@ -54,31 +54,48 @@ jobs:
           BASE_MEMORY=$(cat ./artifacts/memory-base.json)
           HEAD_MEMORY=$(cat ./artifacts/memory-head.json)
 
-          calc() {
-            BASE=$(echo "$BASE_MEMORY" | jq -r '.memory.'"$1"' // 0')
-            HEAD=$(echo "$HEAD_MEMORY" | jq -r '.memory.'"$1"' // 0')
+          variation() {
+            calc() {
+              BASE=$(echo "$BASE_MEMORY" | jq -r ".${1}.${2} // 0")
+              HEAD=$(echo "$HEAD_MEMORY" | jq -r ".${1}.${2} // 0")
 
-            DIFF=$((HEAD - BASE))
-            if [ "$BASE" -gt 0 ]; then
-              DIFF_PERCENT=$(echo "scale=2; ($DIFF * 100) / $BASE" | bc)
-            else
-              DIFF_PERCENT=0
-            fi
+              DIFF=$((HEAD - BASE))
+              if [ "$BASE" -gt 0 ]; then
+                DIFF_PERCENT=$(echo "scale=2; ($DIFF * 100) / $BASE" | bc)
+              else
+                DIFF_PERCENT=0
+              fi
 
-            # Convert KB to MB for readability
-            BASE_MB=$(echo "scale=2; $BASE / 1024" | bc)
-            HEAD_MB=$(echo "scale=2; $HEAD / 1024" | bc)
-            DIFF_MB=$(echo "scale=2; $DIFF / 1024" | bc)
+              # Convert KB to MB for readability
+              BASE_MB=$(echo "scale=2; $BASE / 1024" | bc)
+              HEAD_MB=$(echo "scale=2; $HEAD / 1024" | bc)
+              DIFF_MB=$(echo "scale=2; $DIFF / 1024" | bc)
 
-            echo "$1-base=$BASE_MB" >> "$GITHUB_OUTPUT"
-            echo "$1-head=$HEAD_MB" >> "$GITHUB_OUTPUT"
-            echo "$1-diff=$DIFF_MB" >> "$GITHUB_OUTPUT"
-            echo "$1-diff_percent=$DIFF_PERCENT" >> "$GITHUB_OUTPUT"
+              JSON=$(jq -c -n \
+                --arg base "$BASE_MB" \
+                --arg head "$HEAD_MB" \
+                --arg diff "$DIFF_MB" \
+                --arg diff_percent "$DIFF_PERCENT" \
+                '{base: $base, head: $head, diff: $diff, diff_percent: $diff_percent}')
+
+              echo "$JSON"
+            }
+
+            JSON=$(jq -c -n \
+              --argjson VmRSS "$(calc $1 VmRSS)" \
+              --argjson VmHWM "$(calc $1 VmHWM)" \
+              --argjson VmSize "$(calc $1 VmSize)" \
+              '{VmRSS: $VmRSS, VmHWM: $VmHWM, VmSize: $VmSize}')
+
+            echo "$JSON"
           }
 
-          calc VmRSS
-          calc VmHWM
-          calc VmSize
+          JSON=$(jq -c -n \
+            --argjson beforeGc "$(variation beforeGc)" \
+            --argjson afterGc "$(variation afterGc)" \
+            '{beforeGc: $beforeGc, afterGc: $afterGc}')
+
+          echo "res=$JSON" >> "$GITHUB_OUTPUT"
       - id: build-comment
         name: Build memory comment
         run: |
@@ -88,15 +105,33 @@ jobs:
           echo "$HEADER" > ./output.md
           echo >> ./output.md
 
-          echo "| Metric | base | head | Diff |" >> ./output.md
-          echo "|--------|------|------|------|" >> ./output.md
-          echo "| RSS | ${{ steps.compare.outputs.VmRSS-base }} MB | ${{ steps.compare.outputs.VmRSS-head }} MB | ${{ steps.compare.outputs.VmRSS-diff }} MB (${{ steps.compare.outputs.VmRSS-diff_percent }}%) |" >> ./output.md
-          echo "| HWM | ${{ steps.compare.outputs.VmHWM-base }} MB | ${{ steps.compare.outputs.VmHWM-head }} MB | ${{ steps.compare.outputs.VmHWM-diff }} MB (${{ steps.compare.outputs.VmHWM-diff_percent }}%) |" >> ./output.md
-          echo "| VMS | ${{ steps.compare.outputs.VmSize-base }} MB | ${{ steps.compare.outputs.VmSize-head }} MB | ${{ steps.compare.outputs.VmSize-diff }} MB (${{ steps.compare.outputs.VmSize-diff_percent }}%) |" >> ./output.md
+          table() {
+            line() {
+              BASE=$(echo "${{ steps.compare.outputs.res }}" | jq -r ".${1}.${2}.base")
+              HEAD=$(echo "${{ steps.compare.outputs.res }}" | jq -r ".${1}.${2}.head")
+              DIFF=$(echo "${{ steps.compare.outputs.res }}" | jq -r ".${1}.${2}.diff")
+              DIFF_PERCENT=$(echo "${{ steps.compare.outputs.res }}" | jq -r ".${1}.${2}.diff_percent")
+
+              echo "| ${2} | ${BASE} MB | ${HEAD} MB | ${DIFF} MB (${DIFF_PERCENT}%) |" >> ./output.md
+            }
+
+            echo "| Metric | base | head | Diff |" >> ./output.md
+            echo "|--------|------|------|------|" >> ./output.md
+            line $1 VmRSS
+            line $1 VmHWM
+            line $1 VmSize
+          }
+
+          echo "### Before GC" >> ./output.md
+          table beforeGc
+          echo >> ./output.md
+
+          echo "### After GC" >> ./output.md
+          table afterGc
           echo >> ./output.md
 
           # Determine if this is a significant change (more than 5% increase)
-          if [ "$(echo "${{ steps.compare.outputs.VmRSS-diff_percent }} > 5" | bc)" -eq 1 ]; then
+          if [ "$(echo "${{ steps.compare.outputs.res }}" | jq -r '.afterGc.VmRSS.diff_percent | tonumber > 5')" = "true" ]; then
             echo "⚠️ **Warning**: Memory usage has increased by more than 5%. Please verify this is not an unintended change." >> ./output.md
             echo >> ./output.md
           fi
diff --git a/packages/backend/scripts/measure-memory.mjs b/packages/backend/scripts/measure-memory.mjs
index 82a5a0bf0b..749f550bcc 100644
--- a/packages/backend/scripts/measure-memory.mjs
+++ b/packages/backend/scripts/measure-memory.mjs
@@ -60,9 +60,9 @@ async function measureMemory() {
 			...process.env,
 			NODE_ENV: 'production',
 			MK_DISABLE_CLUSTERING: '1',
-			MK_FORCE_GC: '1',
 		},
 		stdio: ['pipe', 'pipe', 'pipe', 'ipc'],
+		execArgv: [...process.execArgv, '--expose-gc'],
 	});
 
 	let serverReady = false;
@@ -104,9 +104,21 @@ async function measureMemory() {
 	// Wait for memory to settle
 	await setTimeout(MEMORY_SETTLE_TIME);
 
-	// Get memory usage from the server process via /proc
 	const pid = serverProcess.pid;
-	const memoryInfo = await getMemoryUsage(pid);
+
+	const beforeGc = await getMemoryUsage(pid);
+
+	serverProcess.send('gc');
+
+	await new Promise((resolve) => {
+		serverProcess.once('message', (message) => {
+			if (message === 'gc ok') resolve();
+		});
+	});
+
+	await setTimeout(1000);
+
+	const afterGc = await getMemoryUsage(pid);
 
 	// Stop the server
 	serverProcess.kill('SIGTERM');
@@ -129,7 +141,8 @@ async function measureMemory() {
 
 	const result = {
 		timestamp: new Date().toISOString(),
-		memory: memoryInfo,
+		beforeGc,
+		afterGc,
 	};
 
 	return result;
@@ -144,19 +157,23 @@ async function main() {
 	}
 
 	// Calculate averages
-	const avgMemory = structuredClone(keys);
+	const beforeGc = structuredClone(keys);
+	const afterGc = structuredClone(keys);
 	for (const res of results) {
-		for (const key of Object.keys(avgMemory)) {
-			avgMemory[key] += res.memory[key];
+		for (const key of Object.keys(keys)) {
+			beforeGc[key] += res.beforeGc[key];
+			afterGc[key] += res.afterGc[key];
 		}
 	}
-	for (const key of Object.keys(avgMemory)) {
-		avgMemory[key] = Math.round(avgMemory[key] / SAMPLE_COUNT);
+	for (const key of Object.keys(keys)) {
+		beforeGc[key] = Math.round(beforeGc[key] / SAMPLE_COUNT);
+		afterGc[key] = Math.round(afterGc[key] / SAMPLE_COUNT);
 	}
 
 	const result = {
 		timestamp: new Date().toISOString(),
-		memory: avgMemory,
+		beforeGc,
+		afterGc,
 	};
 
 	// Output as JSON to stdout
diff --git a/packages/backend/src/boot/entry.ts b/packages/backend/src/boot/entry.ts
index 56b339b6aa..3a33d198a5 100644
--- a/packages/backend/src/boot/entry.ts
+++ b/packages/backend/src/boot/entry.ts
@@ -86,9 +86,17 @@ if (!envOption.disableClustering) {
 	ev.mount();
 }
 
-if (envOption.forceGc && global.gc != null) {
-	global.gc();
-}
+process.on('message', msg => {
+	if (msg === 'gc') {
+		if (global.gc != null) {
+			logger.info('Manual GC triggered');
+			global.gc();
+			if (process.send != null) process.send('gc ok');
+		} else {
+			logger.warn('Manual GC requested but gc is not available. Start the process with --expose-gc to enable this feature.');
+		}
+	}
+});
 
 readyRef.value = true;
 
diff --git a/packages/backend/src/env.ts b/packages/backend/src/env.ts
index 9957938467..ba44cfa2e6 100644
--- a/packages/backend/src/env.ts
+++ b/packages/backend/src/env.ts
@@ -11,7 +11,6 @@ const envOption = {
 	verbose: false,
 	withLogTime: false,
 	quiet: false,
-	forceGc: false,
 };
 
 for (const key of Object.keys(envOption) as (keyof typeof envOption)[]) {