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From: Pasha Tatashin <pasha.tatashin@oracle.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com,
	tglx@linutronix.de, hpa@zytor.com
Subject: Re: [v1 0/9] Early boot time stamps for x86
Date: Wed, 22 Mar 2017 19:59:43 -0400	[thread overview]
Message-ID: <a3f027ee-c193-2e1f-4f4c-da6cffb80d05@oracle.com> (raw)
In-Reply-To: <20170322202807.y34mrortprg5pi43@hirez.programming.kicks-ass.net>

Hi Peter,

Thank you for looking at this patchset.

Yes, I am certain it is 0 or  near 0 on reset on this machine. Because, 
I actually wondered about it, and used stop watch as an alternative way 
to verify the result, twice.

While, I suspect it is often the case that on reset tsc is 0, it is not 
really import, as the offset value is not the important part of the 
project. The important part is that we can cover the whole Linux boot 
process with timestamps, and know where spend time, and avoid 
regressions in the future.

Thank you,
Pasha

On 2017-03-22 16:28, Peter Zijlstra wrote:
> On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote:
>> - early tsc offset is 549s, so it took over 9 minutes to get through POST,
>>   and GRUB before starting linux
>
> Lol, how cute. You assume TSC starts at 0 on reset.
>

  reply	other threads:[~2017-03-23  0:00 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-22 20:24 Pavel Tatashin
2017-03-22 20:24 ` [v1 1/9] sched/clock: broken stable to unstable transfer Pavel Tatashin
2017-03-27 10:27   ` [tip:sched/urgent] sched/clock: Fix " tip-bot for Pavel Tatashin
2017-03-22 20:24 ` [v1 2/9] sched/clock: interface to allow timestamps early in boot Pavel Tatashin
2017-03-22 20:24 ` [v1 3/9] x86/cpu: determining x86 vendor early Pavel Tatashin
2017-03-22 20:24 ` [v1 4/9] x86/tsc: early MSR-based CPU/TSC frequency discovery Pavel Tatashin
2017-03-22 20:24 ` [v1 5/9] x86/tsc: disable early messages from quick_pit_calibrate Pavel Tatashin
2017-03-22 20:24 ` [v1 6/9] x86/tsc: use cpuid to determine TSC frequency Pavel Tatashin
2017-03-22 20:24 ` [v1 7/9] x86/tsc: use cpuid to determine CPU frequency Pavel Tatashin
2017-03-22 20:24 ` [v1 8/9] x86/tsc: tsc early Pavel Tatashin
2017-03-24  5:38   ` kbuild test robot
2017-03-22 20:24 ` [v1 9/9] x86/tsc: use " Pavel Tatashin
2017-03-22 20:27 ` [v1 0/9] Early boot time stamps for x86 Peter Zijlstra
2017-03-23  0:02   ` Pasha Tatashin
2017-03-22 20:28 ` Peter Zijlstra
2017-03-22 23:59   ` Pasha Tatashin [this message]
2017-03-23 10:56     ` Thomas Gleixner
2017-03-23 14:39       ` Pasha Tatashin
2017-03-23 18:40         ` Thomas Gleixner

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