Using uncompressed kernel

How do I have u-boot load an uncompressed kernel image instead of using uImage? I have searched for several days now and have not found a solution on how to do this. Can someone point me in the right direction? My goal is to have a quicker boot time, and I am wondering if this would help.

How do I have u-boot load an uncompressed kernel image instead of using
uImage?

First, uImage is just a wrapper around zImage, it doesn't add that
much overhead. Rebuild u-boot with:

#define CONFIG_CMD_BOOTZ

Then you can boot the zImage directly, probally only saves you a
couple clock cycles..

I have searched for several days now and have not found a solution
on how to do this.

http://free-electrons.com/blog/arm-xz-kernel-decompression-benchmarks/

Scroll down to "Benchmarks on OMAP4 Panda"

Notice how no-compression is actually worse.. :wink:

Can someone point me in the right direction? My goal is
to have a quicker boot time, and I am wondering if this would help.

We've pretty much set the default to about the fastest all ready.. :wink:

Regards,

Thanks for the link - it was an interesting read. So I suppose the biggest time saver will be making uImage as small as possible by removing all unnecessary configurations so it takes less time to copy and uncompress. What about disabling systemd-fsck on rootfs? I see that it takes 2 seconds to check the disk and can’t seem to find a way to disable it. Or would making the partition smaller help so it doesn’t have as much to check?

Thanks for the link - it was an interesting read. So I suppose the biggest
time saver will be making uImage as small as possible by removing all
unnecessary configurations so it takes less time to copy and uncompress.
What about disabling systemd-fsck on rootfs? I see that it takes 2 seconds
to check the disk and can't seem to find a way to disable it.

Sure, disable that.. Everyone likes a fast system that hard locks on
the eventual random file system errors..

Or would
making the partition smaller help so it doesn't have as much to check?

Well, if your using ext3, switch to ext4 as fast fsck'ing what one of
it's enhancements..

Regards,

Ouch… really? Random file system errors? Even if I shutdown instead of just pulling the plug? I’m already using ext4.

Ouch... really? Random file system errors?

From Random power spikes, random hardlocks (smsc95xx), etc...

Even if I shutdown instead of
just pulling the plug?

Well, if you really do that 100% of the time, you should be fine...
I'd never touch that system with 30 foot pole.

I'm already using ext4.

Regards,

BTW: More here too:
http://elinux.org/Boot_Time

Regards,

Ok, good to know. Sounds like it’s about as lean as it can be and still be reliable. I’m just trying to figure out what I can rip out to gain a few seconds. Thanks for your help!

I believe uImage has additional error checking that zImage doesn't. If
you value the error checking, use uImage.

-Andrew