From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC9E0C43219 for ; Wed, 1 May 2019 11:02:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A60D321743 for ; Wed, 1 May 2019 11:02:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726400AbfEALCP (ORCPT ); Wed, 1 May 2019 07:02:15 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:58092 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726052AbfEALCP (ORCPT ); Wed, 1 May 2019 07:02:15 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DDA5780D; Wed, 1 May 2019 04:02:14 -0700 (PDT) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3AC263F719; Wed, 1 May 2019 04:02:12 -0700 (PDT) Subject: Re: [PATCH] arm64: Demote boot and shutdown messages to pr_debug To: Mark Rutland , Florian Fainelli Cc: Rob Herring , Daniel Thompson , Lorenzo Pieralisi , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Julien Thierry , Will Deacon , open list , rmk+kernel@armlinux.org.uk, Sudeep Holla , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, Steve Capper References: <20190430223835.23513-1-f.fainelli@gmail.com> <20190501104733.GB11740@lakrids.cambridge.arm.com> From: Robin Murphy Message-ID: <61e61f14-c991-179f-66a9-a98dcee6c10b@arm.com> Date: Wed, 1 May 2019 12:02:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190501104733.GB11740@lakrids.cambridge.arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/05/2019 11:47, Mark Rutland wrote: > On Tue, Apr 30, 2019 at 03:38:31PM -0700, Florian Fainelli wrote: >> Similar to commits c68b0274fb3cf ("ARM: reduce "Booted secondary >> processor" message to debug level") and 035e787543de7 ("ARM: 8644/1: Reduce "CPU: >> shutdown" message to debug level"), demote the secondary_start_kernel() >> and __cpu_die() messages from info, respectively notice to debug. While >> we are at it, also do this for cpu_psci_cpu_kill() which is redundant >> with __cpu_die(). >> >> This helps improve the amount of possible hotplug cycles by around +50% >> on ARCH_BRCMSTB. > > Could you elaborate on why that matters? Yeah, in general if you have a slow serial console then removing all the prints from the kernel makes lots of things much faster, but that's not necessarily a good argument for doing so. If that's a problem that really concerns users then I'd have to ask why they aren't using a stricter loglevel or a different console to begin with. > e.g. is this just for testing, or does this matter in some shutdown or > hibernate scenario? > >> Signed-off-by: Florian Fainelli >> --- >> arch/arm64/kernel/psci.c | 2 +- >> arch/arm64/kernel/smp.c | 4 ++-- >> 2 files changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c >> index 8cdaf25e99cd..a78581046c80 100644 >> --- a/arch/arm64/kernel/psci.c >> +++ b/arch/arm64/kernel/psci.c >> @@ -96,7 +96,7 @@ static int cpu_psci_cpu_kill(unsigned int cpu) >> for (i = 0; i < 10; i++) { >> err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); >> if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { >> - pr_info("CPU%d killed.\n", cpu); >> + pr_debug("CPU%d killed.\n", cpu); >> return 0; >> } >> >> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c >> index 824de7038967..71fd2b5a3f0e 100644 >> --- a/arch/arm64/kernel/smp.c >> +++ b/arch/arm64/kernel/smp.c >> @@ -259,7 +259,7 @@ asmlinkage notrace void secondary_start_kernel(void) >> * the CPU migration code to notice that the CPU is online >> * before we continue. >> */ >> - pr_info("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n", >> + pr_debug("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n", >> cpu, (unsigned long)mpidr, >> read_cpuid_id()); > > I generally agree that we don't need to be verbose, and demoting these > to debug is fine, but it's a shame that these won't be accessible in > defconfig. > > I wonder if we should enable DYNAMIC_DEBUG so that we can turn these on > from the kernel command line, or if we should have something like a > verbose_hotplug option specifically for these messages. We've had DYNAMIC_DEBUG=y in defconfig for a while already :/ Robin. > > Thanks, > Mark. > >> update_cpu_boot_status(CPU_BOOT_SUCCESS); >> @@ -348,7 +348,7 @@ void __cpu_die(unsigned int cpu) >> pr_crit("CPU%u: cpu didn't die\n", cpu); >> return; >> } >> - pr_notice("CPU%u: shutdown\n", cpu); >> + pr_debug("CPU%u: shutdown\n", cpu); >> >> /* >> * Now that the dying CPU is beyond the point of no return w.r.t. >> -- >> 2.17.1 >> > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >