linux-kernel - [PATCH v2] sh/irq: use seq_put_decimal_ull

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Message-Id: <20241130134909.171183-1-00107082@163.com>
Date: Sat, 30 Nov 2024 21:49:09 +0800
From: David Wang <00107082@....com>
To: glaubitz@...sik.fu-berlin.de
Cc: dalias@...c.org,
	linux-kernel@...r.kernel.org,
	linux-sh@...r.kernel.org,
	David Wang <00107082@....com>
Subject: [PATCH v2] sh/irq: use seq_put_decimal_ull_width() for decimal values

On a system with n CPUs and m interrupts, there will be n*m decimal
values yielded via seq_printf(.."%10u "..) which has significant costs
parsing format string and is less efficient than
seq_put_decimal_ull_width(). Stress reading /proc/interrupts
indicates ~30% performance improvement with this patch.

Signed-off-by: David Wang <00107082@....com>
---
 arch/sh/kernel/irq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index 4e6835de54cf..9022d8af9d68 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -43,9 +43,9 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 {
 	int j;
 
-	seq_printf(p, "%*s: ", prec, "NMI");
+	seq_printf(p, "%*s:", prec, "NMI");
 	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", per_cpu(irq_stat.__nmi_count, j));
+		seq_put_decimal_ull_width(p, " ", per_cpu(irq_stat.__nmi_count, j), 10);
 	seq_printf(p, "  Non-maskable interrupts\n");
 
 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
-- 
2.39.2