From: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
To: David Wang <00107082@163.com>
Cc: dalias@libc.org, linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org
Subject: Re: [PATCH v2] sh/irq: use seq_put_decimal_ull_width() for decimal values
Date: Thu, 30 Jan 2025 09:28:25 +0100 [thread overview]
Message-ID: <8754dbeecb9ee16f84a82548f5e4121ec422ae3a.camel@physik.fu-berlin.de> (raw)
In-Reply-To: <20241130134909.171183-1-00107082@163.com>
Hi David,
On Sat, 2024-11-30 at 21:49 +0800, David Wang wrote:
> 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@163.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));
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Thanks,
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
prev parent reply other threads:[~2025-01-30 8:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-08 16:26 [PATCH 13/13] sh/irq: use seq_put_decimal_ull_width() for decimal values David Wang
2024-11-30 12:41 ` John Paul Adrian Glaubitz
2024-11-30 12:44 ` John Paul Adrian Glaubitz
2024-11-30 13:34 ` David Wang
2024-11-30 13:49 ` [PATCH v2] " David Wang
2025-01-30 8:28 ` John Paul Adrian Glaubitz [this message]
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