From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 76D692332D6; Tue, 12 Nov 2024 10:38:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731407881; cv=none; b=WvxS4TRRq18rKW5cRZx5+48P/i7ZdNmRvx7mJojkFmeuIh0Qw07lle1NTsHfTjy2m9J7GeA03Y2dnUkapvfk6V7N+dANTx9Q73ilKpv2n1SkqHPw85FoBA5GGVh2m6GIzQzBwoF7RcHZYCLx8iAFm7h+WyiQxWAtW+DICfWDc2I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731407881; c=relaxed/simple; bh=0B3GM3Pdioo3nMOBEQS4Plqu3UZIoKk5afiFKD6k6I8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bHXhKw6h8ANZ2tSrkvGmpm4pLzmfX/rrL+zTxcDTWdecIdD9vI4HYpT8TM3XlUpdkEhV5XvnndZ/KHdjroKliRsno0TZ4BrxEiI1C1tY4P3XjNDngX1V5J8hGoe8Wms8xHq80tHhRiY5b7ZGlr/VfT+aVuKpLfHUG9nyh6+XWqU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hQdaxhCm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hQdaxhCm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D68EC4CECD; Tue, 12 Nov 2024 10:38:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731407881; bh=0B3GM3Pdioo3nMOBEQS4Plqu3UZIoKk5afiFKD6k6I8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hQdaxhCmDtwFf/aDB4nOWh+rAXoNKxtBfDXXlCKyUsYc2iumxTXfDqXp0XZ8pbjhv Og5s/SFxkeoH329erLSDF2XpBH0qyPZTP29yxsdwAXl4bzUVJOYKW+fDSgPDKh6ZMw lz3OcQd0sK6YjeZCZLNZ16U3SlqbKKEDyvreIvtPedaBetNLdFn0+Ic1mmIXimZ6k8 SpOSTa/O+6MAespLoSZaT56ChLgAKN1U21d82bXMTneUlFabnLtULXf9IXEXsMcxQg OhWcj7uBYBtcGngrYZKLwCAXGnAANI5ymkYvgYUW/oBCqJf4RziHX4+UMw8aJe9IMu lcs5WKtO//xhg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: David Wang <00107082@163.com>, Linus Torvalds , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 8/8] proc/softirqs: replace seq_printf with seq_put_decimal_ull_width Date: Tue, 12 Nov 2024 05:37:42 -0500 Message-ID: <20241112103745.1653994-8-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241112103745.1653994-1-sashal@kernel.org> References: <20241112103745.1653994-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.15.171 Content-Transfer-Encoding: 8bit From: David Wang <00107082@163.com> [ Upstream commit 84b9749a3a704dcc824a88aa8267247c801d51e4 ] seq_printf is costy, on a system with n CPUs, reading /proc/softirqs would yield 10*n decimal values, and the extra cost parsing format string grows linearly with number of cpus. Replace seq_printf with seq_put_decimal_ull_width have significant performance improvement. On an 8CPUs system, reading /proc/softirqs show ~40% performance gain with this patch. Signed-off-by: David Wang <00107082@163.com> Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/proc/softirqs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/softirqs.c b/fs/proc/softirqs.c index 12901dcf57e2b..d8f4e7d54d002 100644 --- a/fs/proc/softirqs.c +++ b/fs/proc/softirqs.c @@ -19,7 +19,7 @@ static int show_softirqs(struct seq_file *p, void *v) for (i = 0; i < NR_SOFTIRQS; i++) { seq_printf(p, "%12s:", softirq_to_name[i]); for_each_possible_cpu(j) - seq_printf(p, " %10u", kstat_softirqs_cpu(i, j)); + seq_put_decimal_ull_width(p, " ", kstat_softirqs_cpu(i, j), 10); seq_putc(p, '\n'); } return 0; -- 2.43.0