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Thu, 3 Apr 2025 09:29:07 GMT Received: from zhonhan-gv.qualcomm.com (10.80.80.8) by nasanex01c.na.qualcomm.com (10.45.79.139) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Thu, 3 Apr 2025 02:29:06 -0700 From: Zhongqiu Han To: , , CC: , , Subject: [PATCH] cpuidle: menu: Optimize bucket assignment when next_timer_ns equals KTIME_MAX Date: Thu, 3 Apr 2025 17:28:52 +0800 Message-ID: <20250403092852.1072015-1-quic_zhonhan@quicinc.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nasanex01c.na.qualcomm.com (10.45.79.139) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: tGyUaV91xNkiQfUo-7cu3cd2svw5GMMY X-Authority-Analysis: v=2.4 cv=N/gpF39B c=1 sm=1 tr=0 ts=67ee54e5 cx=c_pps a=JYp8KDb2vCoCEuGobkYCKw==:117 a=JYp8KDb2vCoCEuGobkYCKw==:17 a=GEpy-HfZoHoA:10 a=XR8D0OoHHMoA:10 a=COk6AnOGAAAA:8 a=oV2fX3CoP5SyQ73Pz8oA:9 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-GUID: tGyUaV91xNkiQfUo-7cu3cd2svw5GMMY X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1095,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-04-03_03,2025-04-02_03,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 clxscore=1011 adultscore=0 mlxscore=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 spamscore=0 phishscore=0 suspectscore=0 mlxlogscore=815 malwarescore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2502280000 definitions=main-2504030033 Directly assign the last bucket value instead of calling which_bucket() when next_timer_ns equals KTIME_MAX, the largest possible value that always falls into the last bucket. This avoids unnecessary calculations and enhances performance. Signed-off-by: Zhongqiu Han Reviewed-by: Christian Loehle --- drivers/cpuidle/governors/menu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 39aa0aea61c6..8fc7fbed0052 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -255,7 +255,12 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, */ data->next_timer_ns = KTIME_MAX; delta_tick = TICK_NSEC / 2; - data->bucket = which_bucket(KTIME_MAX); + /* + * Assign the last bucket value directly instead of calling + * which_bucket(), since KTIME_MAX is the largest possible + * value that always falls into the last bucket. + */ + data->bucket = BUCKETS - 1; } if (unlikely(drv->state_count <= 1 || latency_req == 0) ||