Date: Thu, 19 Apr 2018 20:59:34 +0000 From: Colin Percival <cperciva@tarsnap.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: RFC: Hiding per-CPU kernel output behind bootverbose Message-ID: <01000162dfb48d86-02daee46-919a-4193-84d2-5352d6b05107-000000@email.amazonses.com> In-Reply-To: <20180419204405.GE6887@kib.kiev.ua> References: <01000162df15f856-1e5d2641-2a72-4250-8d8e-adcd47bc5db4-000000@email.amazonses.com> <20180419204405.GE6887@kib.kiev.ua>
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On 04/19/18 13:44, Konstantin Belousov wrote: > On Thu, Apr 19, 2018 at 06:06:21PM +0000, Colin Percival wrote: >> On large systems (e.g., EC2's x1e.32xlarge instance type, with 128 vCPUs) >> the boot time console output contains a large number of lines of the forms >> >> SMP: AP CPU #N Launched! >> cpuN: <ACPI CPU> on acpi0 >> estN: <Enhanced SpeedStep Frequency Control> on cpuN >> >> Having 128 almost-identical lines of output doesn't seem very useful, and >> it actually has a nontrivial impact on the time spent booting. >> >> Does anyone mind if I hide these by default, having them only show up if >> boot verbosity is requested? > > The 'CPU XX Launched' messages are very useful for initial diagnostic > of the SMP startup failures. You need to enable bootverbose to see the > hang details, but for initial hint they are required. Unfortunately, AP > startup hangs occur too often to pretend that this can be delegated to > very specific circumstances. Do SMP startup failures need to be debugged often enough to justify having this verbosity every time a FreeBSD system boots? > Rest of the lines you pasted are normal device attach messages, so it is > not clear how would you hide them without ugly hacks. I would be willing to employ ugly hacks in order to silence unhelpful output and speed up the boot process. -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid
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