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Hi,
I know linux and glibc have optimized memcpy functions for armv5, does the same
hold true
for armv4? If so, is it worth considering putting those in uboot for testing?
regards,
Koen
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Hi
Some time ago I did some speed optimization/investigation with uboot.
I found that the memcpy/memmove function used in uboot is VERY SLOW
compared to the one supplied with the Linux kernel.
I found that an uncompressed kernel with CRC check off and the use of the
memcpy routine drastically decreased the thime spent in uboot.
With an Freescale i.mx21 (mx21.ads board) I could boot uboot within appr.
200us (time from boot until jump to kernel, this is including an
uncompressed kernel copied to mem).
The penalty is ofcourse the larger kernel size in flash.
One comment though is that my kernel was appr. 3MB uncompressed.
I had a minimum kernel configuration with cramfs, ethernet and busybox.
Total boot including uboot was appr. 0.9 secs.
Best wishes,
Mads.
[EMAIL PROTECTED] wrote on 20-02-2007
16:21:43:
> Here are the results (configuration at the end of the message).
>
> * Times are in seconds
> * Total time is time from power-on to bash prompt
> * u-boot time is time from power-on to start of kernel (include crc
> check time
> and uncompression time when applicable)
> * Kernel time is time start of kernel to bash prompt
>
> zImage (size in flash: 1.9M)
> Mem: 125824KB available (3264K code, 630K data, 128K init)
> boot time, with crc check : 7.366/3.890/3.476 (total/kernel/u-boot)
> boot time, without crc check : 6.679/3.898/2.781 (total/kernel/u-boot)
>
> Image (size in flash: 3.8M)
> Mem: 125824KB available (3264K code, 630K data, 128K init)
> boot time, with crc check : 7.015/3.875/3.140 (total/kernel/u-boot)
> boot time, without crc check : 5.609/3.875/1.734 (total/kernel/u-boot)
>
> xipImage (size in flash: 3.8M)
> Mem: 129152KB available (3247K code, 662K data, 16K init)
> boot time, with crc check : 7.967/5.921/2.046 (total/kernel/u-boot)
> boot time, without crc check : 6.561/5.921/0.640 (total/kernel/u-boot)
>
> Comments:
> + XIP uses less RAM (~3.2 Mo less), since the kernel code is in flash
> - XIP kernel is very slow to boot, time earned in u-boot is lost in
kernel.
> * The faster boot is obtained using an uncompressed kernel Image, and
not
> checking the crc
>
> An finally a question:
> Is there any interest in the XIP code in the arm-linux community?
> Other comments???
>
> Marc
>
>
>
> *************************************
> Configuration:
> arm920t @ 180 MHz (at91rm9200 custom board)
> 128Mo of SDRAM and 16 Mo of flash
> linux kernel 2.6.19 + maxim.org.za patches configured with a LOT of
options
> u-boot 1.1.4 + custom patches
> root file system on nfs (init=/bin/bash)
>
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