Messages in this thread | | | Date | Wed, 27 Sep 2017 20:11:40 +0200 | From | Peter Zijlstra <> | Subject | 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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