diff --git a/apps/server/src/domains/game/application/services/GameRoomSession.ts b/apps/server/src/domains/game/application/services/GameRoomSession.ts
index e946f48..e7af619 100644
--- a/apps/server/src/domains/game/application/services/GameRoomSession.ts
+++ b/apps/server/src/domains/game/application/services/GameRoomSession.ts
@@ -123,6 +123,9 @@
       callbacks: loopCallbacks,
     });
 
+    // startDelayMs の待機中にJITとボット初期状態を準備する
+    this.gameLoop.warmUp();
+
     if (startDelayMs === 0) {
       this.gameLoop.start();
       return;
diff --git a/apps/server/src/domains/game/application/services/bot/orchestrators/BotTurnOrchestrator.ts b/apps/server/src/domains/game/application/services/bot/orchestrators/BotTurnOrchestrator.ts
index 9550ec8..f7a47d1 100644
--- a/apps/server/src/domains/game/application/services/bot/orchestrators/BotTurnOrchestrator.ts
+++ b/apps/server/src/domains/game/application/services/bot/orchestrators/BotTurnOrchestrator.ts
@@ -37,7 +37,7 @@
   public decide(
     botPlayerId: BotPlayerId,
     player: Player,
-    gridColors: number[],
+    gridColors: readonly number[],
     nowMs: number,
     elapsedMs: number,
   ): BotDecision {
diff --git a/apps/server/src/domains/game/application/services/bot/policies/TargetSelectionPolicy.ts b/apps/server/src/domains/game/application/services/bot/policies/TargetSelectionPolicy.ts
index 06788e5..683d0e4 100644
--- a/apps/server/src/domains/game/application/services/bot/policies/TargetSelectionPolicy.ts
+++ b/apps/server/src/domains/game/application/services/bot/policies/TargetSelectionPolicy.ts
@@ -21,7 +21,7 @@
 };
 
 const getCellTeamId = (
-  gridColors: number[],
+  gridColors: readonly number[],
   col: number,
   row: number,
   cols: number,
@@ -33,7 +33,7 @@
 export const chooseNextTarget = (
   col: number,
   row: number,
-  gridColors: number[],
+  gridColors: readonly number[],
   size: MapGridSize,
 ): BotTarget => {
   const { UNPAINTED_PRIORITY_STRENGTH } = config.BOT_AI_CONFIG;
diff --git a/apps/server/src/domains/game/application/services/gameResultCalculator.ts b/apps/server/src/domains/game/application/services/gameResultCalculator.ts
index c5287fb..0010088 100644
--- a/apps/server/src/domains/game/application/services/gameResultCalculator.ts
+++ b/apps/server/src/domains/game/application/services/gameResultCalculator.ts
@@ -17,7 +17,7 @@
 
 /** グリッド色配列とプレイヤー情報からゲーム結果ペイロードを生成する */
 export const buildGameResultPayload = (
-  gridColors: number[],
+  gridColors: readonly number[],
   players?: PlayerStatsSource[],
 ): GameResultPayload => {
   const { TEAM_COUNT } = config.GAME_CONFIG;
diff --git a/apps/server/src/domains/game/entities/map/MapStore.ts b/apps/server/src/domains/game/entities/map/MapStore.ts
index 6742b1c..17bb588 100644
--- a/apps/server/src/domains/game/entities/map/MapStore.ts
+++ b/apps/server/src/domains/game/entities/map/MapStore.ts
@@ -47,8 +47,8 @@
     return updates;
   }
 
-  /** 現在のマップ塗り状態をスナップショットとして返す */
-  public getGridColorsSnapshot(): number[] {
-    return [...this.gridColors];
+  /** 現在のマップ塗り状態を読み取り専用参照として返す（コピーなし） */
+  public getGridColorsSnapshot(): readonly number[] {
+    return this.gridColors;
   }
 }
\ No newline at end of file
diff --git a/apps/server/src/domains/game/loop/GameLoop.ts b/apps/server/src/domains/game/loop/GameLoop.ts
index d052cb9..42bb4c9 100644
--- a/apps/server/src/domains/game/loop/GameLoop.ts
+++ b/apps/server/src/domains/game/loop/GameLoop.ts
@@ -56,6 +56,15 @@
 
 type DamageSource = "bomb" | "hurricane";
 
+/** 1秒間のパフォーマンス統計蓄積バッファ */
+type PerfAccumulator = {
+  windowStartMs: number;
+  tickCount: number;
+  totalTickMs: number;
+  maxTickMs: number;
+  totalPayloadBytes: number;
+};
+
 /** ルーム内ゲーム進行を定周期で実行するループ管理クラス */
 export class GameLoop {
   private loopId: NodeJS.Timeout | null = null;
@@ -71,6 +80,13 @@
   private botTurnOrchestrator: BotTurnOrchestrator;
   private readonly botReceivedHitCountById = new Map<string, number>();
   private readonly hurricaneSystem: HurricaneSystem;
+  private perfAccumulator: PerfAccumulator = {
+    windowStartMs: 0,
+    tickCount: 0,
+    totalTickMs: 0,
+    maxTickMs: 0,
+    totalPayloadBytes: 0,
+  };
 
   private readonly roomId: string;
   private readonly tickRate: number;
@@ -94,6 +110,32 @@
     this.callbacks = options.callbacks;
   }
 
+  /**
+   * ゲーム開始前にJITコンパイルを誘発し，全ボットの初期目標を設定する
+   * startDelayMs の待機中に呼ぶことで tick1 のスパイクを抑制する
+   */
+  public warmUp(): void {
+    const nowMs = Date.now();
+    const gridColorsSnapshot = this.mapStore.getGridColorsSnapshot();
+
+    this.players.forEach((player) => {
+      if (
+        isBotPlayerId(player.id) ||
+        this.disconnectedBotControlledPlayerIds.has(player.id)
+      ) {
+        // decide() を呼んでJITコンパイルを誘発し初期目標を隣接セルに設定する
+        // 戻り値は使用しない（位置更新・爆弾設置コールバックは発火しない）
+        this.botTurnOrchestrator.decide(
+          player.id as BotPlayerId,
+          player,
+          gridColorsSnapshot,
+          nowMs,
+          0,
+        );
+      }
+    });
+  }
+
   start() {
     // 既にループが回っている場合は何もしない
     if (this.isRunning) return;
@@ -104,6 +146,13 @@
       nowMs + config.GAME_CONFIG.GAME_DURATION_SEC * 1000;
     this.nextTickAtMs = nowMs + this.tickRate;
     this.lastSentPlayers.clear();
+    this.perfAccumulator = {
+      windowStartMs: nowMs,
+      tickCount: 0,
+      totalTickMs: 0,
+      maxTickMs: 0,
+      totalPayloadBytes: 0,
+    };
     this.isRunning = true;
     this.scheduleNextTick();
 
@@ -161,11 +210,11 @@
   }
 
   private processSingleTick(): void {
-    const monotonicNowMs = performance.now();
+    const tickStartMs = performance.now();
     const wallClockNowMs = Date.now();
     const elapsedMs = Math.max(
       0,
-      Math.round(monotonicNowMs - this.startMonotonicTimeMs),
+      Math.round(tickStartMs - this.startMonotonicTimeMs),
     );
     this.hurricaneSystem.ensureSpawned(elapsedMs);
     this.hurricaneSystem.update(this.tickRate / 1000);
@@ -175,12 +224,63 @@
     this.detectBotBombHits(elapsedMs, wallClockNowMs);
     const tickData = this.buildTickData(elapsedMs);
     this.callbacks.onTick(tickData);
+
+    // パフォーマンス統計を蓄積し，1秒ごとにログ出力する
+    const tickMs = performance.now() - tickStartMs;
+    const payloadBytes = JSON.stringify(tickData).length;
+    this.accumulatePerfStats(tickMs, payloadBytes);
+  }
+
+  /** tick処理時間とペイロードサイズを蓄積し，1秒経過でログを出力する */
+  private accumulatePerfStats(tickMs: number, payloadBytes: number): void {
+    const acc = this.perfAccumulator;
+    acc.tickCount += 1;
+    acc.totalTickMs += tickMs;
+    acc.maxTickMs = Math.max(acc.maxTickMs, tickMs);
+    acc.totalPayloadBytes += payloadBytes;
+
+    const windowMs = performance.now() - acc.windowStartMs;
+    if (windowMs < 1000) return;
+
+    const playerCount = this.players.size;
+    const avgTickMs =
+      acc.tickCount > 0
+        ? Math.round((acc.totalTickMs / acc.tickCount) * 10) / 10
+        : 0;
+    const maxTickMs = Math.round(acc.maxTickMs * 10) / 10;
+    const cpuUsagePct =
+      Math.round((acc.totalTickMs / windowMs) * 1000) / 10;
+    const avgPayloadBytesPerTick =
+      acc.tickCount > 0 ? Math.round(acc.totalPayloadBytes / acc.tickCount) : 0;
+    const outboundBytesPerSec = avgPayloadBytesPerTick * playerCount * acc.tickCount;
+
+    logEvent(logScopes.GAME_LOOP, {
+      event: gameDomainLogEvents.PERF_STATS,
+      result: logResults.STATS,
+      roomId: this.roomId,
+      playerCount,
+      tickCount: acc.tickCount,
+      avgTickMs,
+      maxTickMs,
+      cpuUsagePct,
+      avgPayloadBytesPerTick,
+      outboundBytesPerSec,
+    });
+
+    // ウィンドウをリセット
+    this.perfAccumulator = {
+      windowStartMs: performance.now(),
+      tickCount: 0,
+      totalTickMs: 0,
+      maxTickMs: 0,
+      totalPayloadBytes: 0,
+    };
   }
 
   private updateBotPlayers(
     nowMs: number,
     elapsedMs: number,
-    gridColorsSnapshot: number[],
+    gridColorsSnapshot: readonly number[],
   ): void {
     this.players.forEach((player) => {
       if (
diff --git a/apps/server/src/logging/constants/eventNames.ts b/apps/server/src/logging/constants/eventNames.ts
index 0aed1a4..7a689f7 100644
--- a/apps/server/src/logging/constants/eventNames.ts
+++ b/apps/server/src/logging/constants/eventNames.ts
@@ -27,6 +27,7 @@
   PLAYER_MOVE: "PLAYER_MOVE",
   PLAYER_REMOVE: "PLAYER_REMOVE",
   GAME_LOOP: "GAME_LOOP",
+  PERF_STATS: "PERF_STATS",
 } as const;
 
 /** Roomドメインサービスログで利用するイベント名定数 */
diff --git a/apps/server/src/logging/constants/results.ts b/apps/server/src/logging/constants/results.ts
index 6ab8c75..03131c0 100644
--- a/apps/server/src/logging/constants/results.ts
+++ b/apps/server/src/logging/constants/results.ts
@@ -32,6 +32,7 @@
   REMOVED: "removed",
   SESSION_DISPOSED_EMPTY_ROOM: "session_disposed_empty_room",
   STARTED: "started",
+  STATS: "stats",
   STOPPED: "stopped",
   TRANSFERRED: "transferred",
 } as const;
diff --git a/apps/server/src/logging/contracts/payloadByScope.ts b/apps/server/src/logging/contracts/payloadByScope.ts
index 6232381..f1dc1ee 100644
--- a/apps/server/src/logging/contracts/payloadByScope.ts
+++ b/apps/server/src/logging/contracts/payloadByScope.ts
@@ -199,8 +199,8 @@
   | GamePlayerOperationServiceMoveLogPayload
   | GamePlayerOperationServiceRemoveLogPayload;
 
-/** GameLoopスコープのログ契約 */
-type GameLoopLogPayload = {
+/** GameLoopのライフサイクルログ契約 */
+type GameLoopLifecycleLogPayload = {
   event: typeof gameDomainLogEvents.GAME_LOOP;
   result:
     | typeof logResults.STARTED
@@ -208,6 +208,32 @@
   roomId: string;
 };
 
+/** GameLoopの1秒間パフォーマンス統計ログ契約 */
+type GameLoopPerfStatsLogPayload = {
+  event: typeof gameDomainLogEvents.PERF_STATS;
+  result: typeof logResults.STATS;
+  roomId: string;
+  /** ルーム内プレイヤー数 */
+  playerCount: number;
+  /** 1秒間に処理したtick数（期待値: 20） */
+  tickCount: number;
+  /** tick処理の平均時間（ms） */
+  avgTickMs: number;
+  /** tick処理の最大時間（ms） */
+  maxTickMs: number;
+  /** tick処理時間の合計 / 計測ウィンドウ × 100（%） */
+  cpuUsagePct: number;
+  /** 1tickあたりの平均ペイロードサイズ（bytes，JSON推定値） */
+  avgPayloadBytesPerTick: number;
+  /** 1秒間の送信バイト数推定（avgPayloadBytesPerTick × playerCount × tickCount） */
+  outboundBytesPerSec: number;
+};
+
+/** GameLoopスコープのログ契約 */
+type GameLoopLogPayload =
+  | GameLoopLifecycleLogPayload
+  | GameLoopPerfStatsLogPayload;
+
 /** GameRoomSessionスコープのログ契約 */
 type GameRoomSessionLogPayload = {
   event: typeof gameDomainLogEvents.MOVE;