Slow boot speed of the pre compared to other embedded devices - why?

[tdo]

Hello all,

We all know the pre is pretty slow to boot... and this is even more glaring compared to other embedded devices.

A Nokia N800 (128MB RAM, OMAP 2420 at 400MHz) boots in one third of the time as a Pre- (oc'd@1GHz, webos 2.1)... and it is also a full linux system based on debian with a custom window manager.
My galaxy tab (1GHz) is even faster than the N800.
My EEE PC, with SSD, boots to kubuntu 10.10 login screen in max 15 seconds and a few more seconds to usable desktop.

Now, usually the culprit is(was) the slow hard disk access time (random access), as usually at boot a lot of files need to be read scattered throughout the disk. SSD disks on PCs (i.e. flash, like on embedded devices) cut boot time by a tremendous amount. Usually SSD have 30x or faster random access time than a physical disk (sequential read is more on par, with maybe a 2-3 speedup).

Now a device such as a pre, galaxy tab, or n800 has the OS on flash, which is should be fast to get the data from. So the rest of the time is initialization of drivers, filesystem checks, etc.

But the pre is just waaay too slow at boot compared to the other devices and I cannot find a reason for it.

The time where the static logo (pinguin, or hp/palm logo without glow) is on screen corresponds to the kernel loading and init of the subsystem.

When the logo starts to glow this is when the LunaSysMgr is loading; that is the window manager that displays the cards and manages the user input.

The first part slowness could be linked to checking filesystem if the device was improperly turned off, but actually it's not that which takes the time (dmesg on a console for info)

Even that second part, LunaSysMgr starting up, seems waaay to slow. What could be the reason? Is it read speed? Flash can be read at about 50MB per second (conservatively, but sequential). In 1 minute, that's 3GB of data that is read... so no, can't be that much data that is loaded... the whole os (see the webos doctor) is about 200MB...

So what else is going on behind the scenes? It can't be that loading the window manager, scanning the partition to load the icons to display, and setting up the services takes so much time....

So, end rant: how do you guys, especially you guys compiling kernels and doing low-level stuff, explain the boot time of the pre?

Maybe some major flash initialization issue? Or some filesystem issue? Or maybe is it just "normal" - in which case why are the N800 (clearly underpowered compared to a pre) or a galaxy tab (faster, or on par to an oc'd pre) are speedier?

Please comment! I'm really curious about what could be an explanation for that.


Best,
tdo

[rsanchez1]

I don't know what makes it boot so slowly, but I do know the Pre 2 boots noticeably more quickly.

-- Sent from my Palm Pre using Forums

[greenoyster]

LunaSysMgr also runs all of the Javascript apps. Try "stop LunaSysMgr" and run it directly from the command line (make sure you're logged in as root) so you can see everything it's doing.

[Furuboru]

First step: State the problem.

I wonder if we can speed this up as well.

[tdo]

@greenoyster: good idea. Still that must be an awful lot of scripts... Of course js is much slower than native...

@sanchez: is it right the Pre2 is at 1GHz from the boot, whereas with an overclocked kernel it starts at the normal speed (500) then moves to the oclocked speed at some later point.

@furuboru: there's no problem, just curiosity and the desire to understand the breakdown of time used by program/function/boot stage. Of course would be nicer if it was faster. Can also be that this wasn't at all optimized as normally the phone should always be on, not booted up.

Best,
tdo