linux-kernel - [PATCH net-next] net: sched: cake: Optimize number of calls to cake

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Message-Id: <20240406235532.613696-1-visitorckw@gmail.com>
Date: Sun,  7 Apr 2024 07:55:32 +0800
From: Kuan-Wei Chiu <visitorckw@...il.com>
To: toke@...e.dk
Cc: jhs@...atatu.com,
	xiyou.wangcong@...il.com,
	jiri@...nulli.us,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	jserv@...s.ncku.edu.tw,
	cake@...ts.bufferbloat.net,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Kuan-Wei Chiu <visitorckw@...il.com>
Subject: [PATCH net-next] net: sched: cake: Optimize number of calls to cake_heapify()

Improve the max-heap construction process by reducing unnecessary
heapify operations. Specifically, adjust the starting condition from
n / 2 to n / 2 - 1 in the loop that iterates over all non-leaf
elements.

Signed-off-by: Kuan-Wei Chiu <visitorckw@...il.com>
---
 net/sched/sch_cake.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index edee926ccde8..2eabc4dc5b79 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -1512,7 +1512,7 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
 	if (!q->overflow_timeout) {
 		int i;
 		/* Build fresh max-heap */
-		for (i = CAKE_MAX_TINS * CAKE_QUEUES / 2; i >= 0; i--)
+		for (i = CAKE_MAX_TINS * CAKE_QUEUES / 2 - 1; i >= 0; i--)
 			cake_heapify(q, i);
 	}
 	q->overflow_timeout = 65535;
-- 
2.34.1