linux-kernel - Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2]

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Message-ID: <alpine.DEB.2.11.1601131443380.3575@nanos>
Date:	Wed, 13 Jan 2016 14:45:54 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Prarit Bhargava <prarit@...hat.com>
cc:	linux-kernel@...r.kernel.org, John Stultz <john.stultz@...aro.org>,
	Xunlei Pang <pang.xunlei@...aro.org>,
	Baolin Wang <baolin.wang@...aro.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Petr Mladek <pmladek@...e.cz>, Tejun Heo <tj@...nel.org>,
	Peter Hurley <peter@...leysoftware.com>,
	Vasily Averin <vvs@...tuozzo.com>,
	Joe Perches <joe@...ches.com>
Subject: Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2]

On Wed, 13 Jan 2016, Prarit Bhargava wrote:
> This patchset introduces additional NMI safe timekeeping functions and the
> kernel parameter printk.clock=[local|boot|real|tai] allowing a
> user to specify an adjusted clock to use with printk timestamps.  The
> hardware clock, or the existing functionality, is preserved by default.

You still fail to explain WHY we need a gazillion of different clocks
here.

What's the problem with using the fast monotonic clock instead of local_clock
and be done with it? I really don't see the point why we would need
boot/real/tai and all the extra churn in the fast clock.

Thanks,

	tglx