From mboxrd@z Thu Jan  1 00:00:00 1970
From: js@sig21.net (Johannes Stezenbach)
Date: Tue, 19 Jan 2010 12:04:08 +0100
Subject: Kernel Start-up Time
In-Reply-To: <201001181010.01975.caglarakyuz@gmail.com>
References: <201001181010.01975.caglarakyuz@gmail.com>
Message-ID: <20100119110408.GB9187@sig21.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Jan 18, 2010 at 10:10:01AM +0200, Caglar Akyuz wrote:
> 
> While measuring Linux start-up time, I see that printing version string in 
> "start_kernel" takes ~1.3 seconds. I guess this is the time between from 
> "bootloader jumping to uImage" and "printing version string in generic 
> start_kernel code". Relevant part of my boot log is attached.
> 
> My question: is it normal this 1.3 sec init time? My system is 297 MHZ 
> arm926ej-s with a 162MHZ DDR2 memory.

> [    4.700896] Starting kernel ...
> [    4.702971]
> [    5.966039] [    0.000000] Linux version 2.6.30-davinci1-06079-g4e73fae-

Actually printk goes to a buffer which is output only after the
serial console has been initialized (unless you use some
kind of early printk).  So to find out what causes the delay
look further down in your kernel messages, and look at the kernel
timestamps not the ptx_ts ones.


HTH
Johannes