4 ms·

> critically for embedded environments - startup time improvements. This is so true. Back in the day when I was involve in embedded Linux development, the quic

> critically for embedded environments - startup time improvements. This is so true. Back in the day when I was involve in embedded Linux development, the quickest bootup time was about 40secs. This was booting a v2.6 kernel in a minimum configuration on an ARM7 system over SPI NAND FLASH. Hopefully, the bootup time is in the subseconds by now. Are we getting to these speed yet?

_pmf_ 10y ago
> This is so true. Back in the day when I was involve in embedded Linux development, the quickest bootup time was about 40secs. This was booting a v2.6 kernel in a minimum configuration on an ARM7 system over SPI NAND FLASH. The older NAND file systems were very slow. I've had a similar case where repartitioning the huge NAND into a smaller partition and only using a small partition reduced the boot time to 10 seconds without any other change. Modern UBIFS systems apparently don't have this problem. As for subsecond boot times: no chance with Linux.
- yitchelle 10y ago
  Just looked up what UBIFS is, and saw the reference to JFFS2. We tried JFFS, it was painfully slow. JFFS2 was emerging and tried that too. In reality, it did not really worked for booting up. Once it was up, it was pretty good. Unfortunately, we were developing a hand hand consumer electronics device, so boot up times were absolutely critical.
- rkeene2 10y ago
  I've booted Linux in sub-second times using User Mode Linux so there's nothing actually preventing it other than the need to probe hardware in various slow ways, which could be improved.
  - yitchelle 10y ago
    So this is going from connecting power to having a full system ready to go?
    - rkeene2 10y ago
      The question doesn't really make sense since there's no "power" involved -- the kernel neither has nor lacks power... but if I understand the nature of the question, then the answer is "yes" -- the system goes from not existing to being at a bash prompt in under 0.3s on my laptop.
kbart 10y ago
"Hopefully, the bootup time is in the subseconds by now. Are we getting to these speed yet?" You can do that[0] with minimal system. Actually, it's not that difficult to get booting time down to few seconds on most embedded systems. But in real world boot time highly depends on modules and drivers that must be loaded to make system up and running. http://www.makelinux.com/emb/fastboot/omap http://www.makelinux.com/emb/fastboot/omap
Fredej 10y ago
I'm working on a system which some decently advanced functionality booting a linux 3.14 kernel on an ARM. Currently I'm getting around ~5 seconds, from turning the power on to having the system fully loaded and ready. I could possibly get it lower but it meets spec and any additional shaving off would probably require plenty of work while sacrificing debug-ability etc. so for now I'm fine where it is :)

_pmf_ 10y ago

> This is so true. Back in the day when I was involve in embedded Linux development, the quickest bootup time was about 40secs. This was booting a v2.6 kernel in a minimum configuration on an ARM7 system over SPI NAND FLASH. The older NAND file systems were very slow. I've had a similar case where repartitioning the huge NAND into a smaller partition and only using a small partition reduced the boot time to 10 seconds without any other change. Modern UBIFS systems apparently don't have this problem. As for subsecond boot times: no chance with Linux.

yitchelle 10y ago
Just looked up what UBIFS is, and saw the reference to JFFS2. We tried JFFS, it was painfully slow. JFFS2 was emerging and tried that too. In reality, it did not really worked for booting up. Once it was up, it was pretty good. Unfortunately, we were developing a hand hand consumer electronics device, so boot up times were absolutely critical.
rkeene2 10y ago
I've booted Linux in sub-second times using User Mode Linux so there's nothing actually preventing it other than the need to probe hardware in various slow ways, which could be improved.
- yitchelle 10y ago
  So this is going from connecting power to having a full system ready to go?
  - rkeene2 10y ago
    The question doesn't really make sense since there's no "power" involved -- the kernel neither has nor lacks power... but if I understand the nature of the question, then the answer is "yes" -- the system goes from not existing to being at a bash prompt in under 0.3s on my laptop.

kbart 10y ago

"Hopefully, the bootup time is in the subseconds by now. Are we getting to these speed yet?" You can do that[0] with minimal system. Actually, it's not that difficult to get booting time down to few seconds on most embedded systems. But in real world boot time highly depends on modules and drivers that must be loaded to make system up and running. http://www.makelinux.com/emb/fastboot/omap http://www.makelinux.com/emb/fastboot/omap

Fredej 10y ago

I'm working on a system which some decently advanced functionality booting a linux 3.14 kernel on an ARM. Currently I'm getting around ~5 seconds, from turning the power on to having the system fully loaded and ready. I could possibly get it lower but it meets spec and any additional shaving off would probably require plenty of work while sacrificing debug-ability etc. so for now I'm fine where it is :)