Optimization of linux kernel & uboot

Hi Srini,

1) How unwanted core drivers(mainly i want to remove SGX driver & other core drivers as well) can removed in menuconfig

Yes, you can remove the unwanted driver through menuconfig option.

2) After removing few unwanted drivers in menuconfig the .config which am going to get , how this .config can be loaded (resused) for further removing unwanted driver modules (along with already removed  few unwanted drivers) by loading it in menuconfig again

It would get update every time when you call menuconfig and you can see ".config saved or updated" like that.

3)Basically I will be using the following controllers in my custom board, could anybody please let me know what is the boot time roughly can be reduced only which these core drivers after removing the unwanted drivers apart from the following

Please refer to the following TI wikis.

http://processors.wiki.ti.com/index.php/Boot_Time_Optimization

http://processors.wiki.ti.com/index.php/Optimize_Linux_Boot_Time

http://processors.wiki.ti.com/index.php/All_This_For_1_Second_Boot

Thanks a lot for your replies Titus,

I need some more clarification w.r.t .retaining the .config changes everytime, as am using following commands everytime

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- mrproper
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- tisdk_am335x-evm_defconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- menuconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- uImage dtbs

As menuconfig is GUI of tisdk_am335x-evm_defconfig, Now should I use only the following commands inorder to retain the previous .config changes & do some more changes on this .config(along with the previous changes)

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- menuconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- uImage dtbs

Could you please clarify on the same am bit confused on this can you please correct me with correct & detailed steps,

could you please do the needful as early as poosible

Many thanks in advance

Hi Srini,

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- mrproper   ---> To Clean the all old configured (.config) files and object files
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- tisdk_am335x-evm_defconfig ---> To create default configuration for the TI EVM boards (It would update the .config file)

"mrproper" option is combination of "clean" and "distclean"

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- distclean (It will clean the configuration file (.config))

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- clean  (It will clean the object files)

You have to use the above command only at initial stage (only one time).

After that, we can use the following commands for configuration as well building kernel and dtbs.

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- menuconfig   ----> To select the drivers and linux kernel optons.
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- uImage dtbs   ---> To build/compile the kernel image and dtb files (dtbs)

As menuconfig is GUI of tisdk_am335x-evm_defconfig, Now should I use only the following commands inorder to retain the previous .config changes & do some more changes on this .config(along with the previous changes)

Yes, your understanding is correct.

It is always to take a backup of ".config" for every good expected boot.

And you can use the backup .config by just copy & paste the .config in linux kernel source "/' location.

Hi Titus,

Thanks for the replies,

It is really helpful,

1)

Now I have customized enough drivers from menuconfig, now I need to use this .conifg always,

I have copied it to '/',  now how can I load this .config everytime, is it necessary to create the defconfig from this .config, if so (please let me know how to create this defconfig)

or

Is there any options in this kernel menuconfig ie., to load this .confif everytime (because in old kernels in menuconfig we had options of loading alternate configuration file but am unable to find this in this kernel ie.,ti-sdk-am335x-evm-07.00.00.00)

Could you please let me know how this customized .config can be loaded every time instead of default configuration

2)

I am trying to measure the boot time (http://processors.wiki.ti.com/index.php/Measuring_Boot_Time)

I have cross compiled tstamp.c & I have loaded the timestamp ie., using

 arm-linux-gnueabihf-gcc timestamp.c -o timestamp & I have copied to /rootfs/usr/bin/

Am trying to run this executable on board as shown below

root@beaglebone:~# timestamp < /dev/ttyO0

But am unable to get any bootprints with time stamps inorder to measure boot time , could you please correct me if am I wrong w.r.t this

Or could you please let me know there any other alternate ways to measure boot time apart from this

Kindly do the needful as early as possible

Many Thanks in advance

Hi Srini,

1)

Now I have customized enough drivers from menuconfig, now I need to use this .conifg always,

I have copied it to '/',  now how can I load this .config everytime, is it necessary to create the defconfig from this .config, if so (please let me know how to create this defconfig)

or

Is there any options in this kernel menuconfig ie., to load this .confif everytime (because in old kernels in menuconfig we had options of loading alternate configuration file but am unable to find this in this kernel ie.,ti-sdk-am335x-evm-07.00.00.00)

Could you please let me know how this customized .config can be loaded every time instead of default configuration

Just copy .config and rename into configs folder.

cp -rf .config arch/arm/configs/titus_am335x_new_defconfig

2) Regarding measuring the boot time,

We have to use any serial port software to read the time stamp.

I have used "timestamp" for reading time for network transfer.

http://processors.wiki.ti.com/index.php/Optimize_Linux_Boot_Time#Measuring_boot_time