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[ts-7000] Re: how hard would it be to have mavcrunch support all through

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Subject: [ts-7000] Re: how hard would it be to have mavcrunch support all throughout debian arm, up
From: "waggywagz" <>
Date: Sun, 09 Jul 2006 17:50:06 -0000
There is a group already working on better ARM FPU support (including
MaverickCrunch) by creating a new target architecture likely to
replace the existing ARM port sometime down the road.

http://wiki.debian.org/ArmEabiPort

This page is being revised frequently, but the gist when I last read
it is that they are planning on having the architecture available in
the next distribution after Etch, though it would be possible to get
it into Etch with some more help.  Since they are targeting a future
distribution, support for use with the older Linux kernel (2.4), gcc,
C libraries, and such backporting will also need to be done by those
who need it in addition to development of the new architecture.  

That said, I don't think your problem with apt-get has much to do with
floating point.  I had the same frustration, but found it was due to
the Debian default of mounting removable media (including SD cards)
synchronously.  Try: 

cat /etc/fstab

If your root filesystem is mounted 'sync' instead of 'async', change
it temporarily with the following command:

mount / -o remount,async

Edit /etc/fstab to change it permanently.

Doing this makes a HUGE difference in overall SD card I/O performance.
 For example, I used a tiny, innocuous package to test apt-get install
(wordplay).  On a TS-7300 with 128MB RAM, it took 35 minutes to
install it with the SD card (1GB, 70% free) mounted synchronously;
mounted asynchronously, it took about 2 minutes.  Installing a much
larger package and its dependancies (vim, 3844kB compressed) took less
than 4 minutes, indicating the base overhead of apt-get install is
close to 2 minutes when the SD card is mounted asynchronously.

Note, as discussed recently in this forum, you may have a Good Reason
to mount an SD card synchronously.  But, if you will be doing a lot of
file access, especially write access or operations involving repeated
reading and writing a file, i think at least your root filesystem
should be mounted asynchronously.

I hope this helps.

-David Wagner

P.S.  The 1 MByte/sec you report from sdparm is raw read speed.  I
have done some testing of TS-SD write speed, and found raw write speed
to be (independent of a card's rating) about 700 kB/sec; dd speed from
one card to another clocks in around 500 kB/sec.  However, typical
filesystem write speed is, as you might expect, a bit less than half
raw write speed at about 300 kB/sec.  Also, whenever I attempted to do
a large card filesystem write (copying or unpacking the root
filesystem to the second SD card, for example), if the filesystems on
the cards were mounted synchronously the operation would fail after
about 40 minutes leaving a partially installed filesystem on the
target with literally thousands of errors.  Mounting the filesystems
asynchronously fixed this. 








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