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Re: [PATCH v6 1/4] sched/clock: interface to allow timestamps early in boot

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On Wed, Sep 27, 2017 at 03:45:06PM +0100, Russell King - ARM Linux wrote:
> On Wed, Aug 30, 2017 at 02:03:22PM -0400, Pavel Tatashin wrote:
> > In Linux printk() can output timestamps next to every line.  This is very
> > useful for tracking regressions, and finding places that can be optimized.
> > However, the timestamps are available only later in boot. On smaller
> > machines it is insignificant amount of time, but on larger it can be many
> > seconds or even minutes into the boot process.
> 
> The sched_clock work I did for ARM could be setup really early at boot,
> from setup_arch().  I tried to encourage platforms to do that, but all
> my encouragement fell on deaf ears - most people setup the sched_clock
> source along side the time initialisation on ARM.
> 
> I don't think we need yet another "early" mechanism to solve this problem,
> we just need people to use the existing mechanism to register their
> sched_clock implementation earlier.

x86 is a bit 'special' in the whole sched_clock department. But yes, we
should very much make the regular sched_clock() happen earlier.

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Re: [PATCH v6 1/4] sched/clock: interface to allow timestamps early  in boot Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-09-27 16:50 +0200
  Re: [PATCH v6 1/4] sched/clock: interface to allow timestamps early  in boot Pasha Tatashin <pasha.tatashin@oracle.com> - 2017-09-27 19:20 +0200
  Re: [PATCH v6 1/4] sched/clock: interface to allow timestamps early  in boot Peter Zijlstra <peterz@infradead.org> - 2017-09-27 20:20 +0200

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