linux-kernel - Re: Kernel without RTC

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Date:   Wed, 8 Mar 2017 13:33:33 +0000
From:   "Hadimani, Jagadish" <Jagadish.Hadimani@....com>
To:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>
CC:     "Shah, Nehal-bakulchandra" <Nehal-bakulchandra.Shah@....com>,
        "a.zummo@...ertech.it" <a.zummo@...ertech.it>,
        "rtc-linux@...glegroups.com" <rtc-linux@...glegroups.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Kernel without RTC

Hello Alexandre,

I guess the Linux kernel uses HPET timer...
But can we can force Linux kernel to use Tsc or per core timer...

Sent from my iPhone

> On 8 Mar 2017, at 6:47 PM, Alexandre Belloni <alexandre.belloni@...e-electrons.com> wrote:
> 
> Hi,
> 
>> On 07/03/2017 at 00:48:18 +0530, Shah, Nehal-bakulchandra wrote:
>> Hi,
>> 
>> Currently we are having hardware which does not have RTC. It is single processor system. However it does have TSC timer.
>> 
>> Now, how to use scheduler with only TSC as current kernel scheduler leverage the RTC for scheduling? I had seen one old patch
>> 
>> http://marc.info/?l=linux-kernel&m=112013203625990&w=2 
>> 
>> But i guess this patch was later on not taken, It will be great if you can some pointers to move forward?
>> 
> 
> The kernel doesn't use the RTC for its time source so it can
> already work without an RTC.
> 
> 
> -- 
> Alexandre Belloni, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com