Re: New fast(?)-boot results on ARM

Dirk Behme
2009-08-15T06:00:15Z

Robert Schwebel wrote:
> On Fri, Aug 14, 2009 at 10:04:57PM +0200, Denys Vlasenko wrote:
>>> rsc@thebe:~$ microcom | ptx_ts "U-Boot 2.0.0-rc9"
>>> [ 2.395740] < 2.395740>
>>> [ 2.395860] < 0.000120>
>>> [ 0.000011] < 0.000011> U-Boot 2.0.0-rc9 (Aug 5 2009 - 10:05:58)
>>> [ 0.000059] < 0.000048>
>>> [ 0.003823] < 0.003764> Board: Phytec phyCORE-i.MX27
>>> [ 0.010753] < 0.006930> cfi_probe: cfi_flash base: 0xc0000000 size: 0x02000000
>>> [ 0.018711] < 0.007958> NAND device: Manufacturer ID: 0x20, Chip ID: 0x36 (ST Micro NAND 64MiB 1,8V 8-bit)
>>> [ 0.026592] < 0.007881> imxfb@imxfb0: i.MX Framebuffer driver
>>> [ 0.178655] < 0.152063> dev_protect: currently broken
>>> [ 0.178736] < 0.000081> Using environment in NOR Flash
>>> [ 0.182577] < 0.003841> initialising PLLs
>>> [ 0.367142] < 0.184565> Malloc space: 0xa3f00000 -> 0xa7f00000 (size 64 MB)
>>> [ 0.370568] < 0.003426> Stack space : 0xa3ef8000 -> 0xa3f00000 (size 32 kB)
>>> [ 0.445993] < 0.075425> running /env/bin/init...
>>> [ 0.870592] < 0.424599>
>>> [ 0.874559] < 0.003967> Hit any key to stop autoboot: 0
>> boot loader is not fast. considering its simple task, it can be made
>> faster.
>
> Yup, will check. Almost 1 s seems really long.

Some things to check regarding this and kernel uncompression (copy):

- How often is (compressed/uncompressed) kernel data copied? Once the
compressed one from storage (NOR/NAND?) to RAM by boot loader? Then by
kernel's uncompression from RAM to it's final location in RAM?

- For boot loader and uncompression, is D-Cache enabled?

- Is data (image) copy done by optimized functions? Using (a) DMA or
at least (b) some optimized memcpy using ARM's ldmia/stmia?

Best regards

Dirk