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Date:      Fri, 1 Mar 2013 01:41:57 +0100
From:      Bernd Walter <ticso@cicely7.cicely.de>
To:        Ian Lepore <ian@freebsd.org>
Cc:        freebsd-arm@freebsd.org
Subject:   Re: PHYSADDR
Message-ID:  <20130301004157.GB64366@cicely7.cicely.de>
In-Reply-To: <1362068453.1195.40.camel@revolution.hippie.lan>
References:  <E886046B-1612-425B-902B-72D4B0E93618@freebsd.org> <1362068453.1195.40.camel@revolution.hippie.lan>

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On Thu, Feb 28, 2013 at 09:20:53AM -0700, Ian Lepore wrote:
> 
> The trampoline is relatively horrible for performance as well, it
> decompresses the kernel to one place, then copies it to another.  I'm
> curious whether anyone uses it at all, except us at Symmetricom?  I'm
> not even sure there's any advantage to us using it.  I suspect it was at
> one time better for performance to load a smaller image from sdcard
> (because that's slow) and take the hit on the decompress time.  Recently
> I enabled the MMU and caches in our low-level bootloader, and I have a
> feeling that plus other changes to the boot sd code may mean it's faster
> to load an uncompressed kernel now.  I need to do some testing.

I think it is from early days when the kernel was loaded from space
limited SPI flash before Warner did the SD support.
I have a 2MB SPI flash on my RM9200 board (Warner did with larger, but
also had placed something else inside)
Without compression it wouldn't have fit:
[54]beaver.cicely.de# ls -al /boot/kernel*
/boot/kernel:
total 5044
drwxr-xr-x  2 root  wheel      512 Nov 22  2009 .
drwxr-xr-x  8 root  wheel      512 Nov 22  2009 ..
-r-xr-xr-x  1 root  wheel  3661569 Nov 22  2009 kernel
-r-xr-xr-x  1 root  wheel  1453672 Nov 22  2009 kernel.gz.tramp

Not sure about actual kernel size, but I don't expect them to be any
smaller.

Btw.
In case anyone have doubts that FreeBSD-arm can be running solid:
[55]beaver.cicely.de# uptime
 1:32AM  up 797 days,  4:42, 1 user, load averages: 0.02, 0.03, 0.00
[56]beaver.cicely.de# uname -a
FreeBSD beaver.cicely.de 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Sun Nov 22 07:52:33 CET 2009     ticso@beaver.cicely.de:/mnt2/arm-2009-04-17/head/sys/arm/compile/BEAVER  arm
The system is running my home automation.

-- 
B.Walter <bernd@bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.



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