Not having to copy ramdisk.gz from flash to RAM

Roberto Waltman rwaltman at electrophysics.com
Fri Aug 10 11:23:29 CDT 2007


Andy Ngo wrote:
> ...   If I use a non-compressed image (ramdisk instead of ramdisk.gz), 
> will it buy me much time?  By that I mean copy time < uncompressing time?

Measure, measure, measure.  In an imaginary system with a slow bandwidth 
interface to the device from where the ramdisk image is copied, but with 
fast ram and a fast processor, using compression would save time.
In another system with a high bandwidth to copy between FLASH and RAM, 
but with a slow processor, not using compression may save time.
You can find out only by testing. (Not necessarily the full boot 
process, but at least having some figures on how long does it take to 
copy N kbytes of data between various devices, how long does it take to 
uncompress a typical ramdisk image, etc,  and extrapolating from there.)




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