On Thursday 05 May 2011 17:32:20 Wolfgang Denk wrote:
Dear Alexander Stein,
In message 201105030848.17576.alexander.stein@systec-electronic.com you
wrote:
This specific version was selected due to relocation problems on ARM. But I expect the dcache doesn't have that big influence on the named code part as the environment is already in RAM.
Your expectation is most likely completely wrong. Reading from / writing to uncached RAM is painfully slow compared to a system with caches turned on. And if you - as I speculate - need to checksum a huge amount of data, this will delay things without need.
Caching has a huge effect on **all** code and is the first thing I'd play with in trying to speed things up.
I have been doing some stuff to speed omap3 booting. It was taking approx 4 seconds from power up until the kernel started spewing boot messages. That is now down to less than 2 secs (including the funky omap3 romboot time, loading uboot from NAND and then loading the kernel from NAND). Only difference was turning on caching in uboot using the caching commands.
-- Charles