[ELDK] memory usage in embedded linux
wd at denx.de
Mon Sep 15 20:16:28 CEST 2008
In message <bb70857e0809150651k5e3470au1d4aa43802df6218 at mail.gmail.com> you wrote:
> There is small question about memory usage in embedded syste,.
It's a small question maybe, but a difficult one :-)
> Uboot takes 200kb in flash
> Kernel compress image take 2Mb in flash.
> compress Root File system takes 10Mb
> After expending and booting in SDRAM.
> Uboot takes 200Kb (for simple calculation i am putting 1Mb)
> Kernel takes 10Mb for example.
> File system expand to 40Mb.
> It means 51Mb memory used.
Now, it depends. This number is almost certainly incorrect.
First, U-Boot doesn;t use any RAM when Linux is running. It gets wiped
Second, file system footprint in RAM depends a lot on which file
system you use. Ramdisk is worst, because you always load everything,
and eventually even copy it again to execute it. Other file systems
like cramfs have a uch smaller RAM footprint as only parts of the
software that are actually needed have to be loaded into RAM. For a
> or How to calculate memory usage for kernel and application and what is safe
I am not aware of any generam tool you just run and which then spits
out some number - you have to carefully investigate each and every
system configuration from ground up, studying all configured
services, used applications, necessary error handling szenarios,
seldom run things like software update tools, etc.
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