Edgy concurrent boot speed

[boban]

Hi!

I have question about concurrent boot in Edgy. How can I configure it? Is it default? Can it be disabled?

And most important:
While rumbling through my config files I saw in /etc/init.d/rc:

# Specify method used to enable concurrent init.d scripts.
# Valid options are 'none', 'shell' and 'startpar'
CONCURRENCY=none

What does it mean? Is this another concurrency option in edgy/linux?

[K.Mandla]

Nice find. I'm going by what I scraped up from Debian Administration, but it looks like you might see a boot time decrease if you change that line to

CONCURRENCY=shell

I'll try it when I get home and see if it has any effect.

I just love speed tweaks!

[kerry_s]

I wouldn't mess with that bad things happen.

[K.Mandla]

Well, I tried it anyway and my boot time went from 28 seconds to 25.5 seconds on a dual 2.8Ghz P4 Xeon machine. No problems or errors as of yet. I'm going to see what happens when I try it on an older laptop ...

Cheers!

[boban]

I did some googling and found, that the main difference between using CONCURRENCY=startpar and CONCURRENCY=shell in /etc/default/rcS is that the latter doesn't care about the order in which messages are printed to the screen[1].

According to some other sites boot speed increase varies from 2-6 sec.

But how can I check/test that normal booting procedure is parallel? Really - I didn't see any boot speed improvement between Dapper and Edgy (but I didn't measure time either, so that is very subjective).

And another thing - about single core cpus... I am a programmer myself and according to my previous experience adding concurrency to programs actually slows them [on single processor/core system] a bit. It's because additional overhead of concurrency control mechanisms and task switching. Parallel execution is only beneficial if some external delays are introduced, like waiting for ip address from dhcp server. So I assume that only some tasks are booting concurrent in Edgy boot-up process... Can I control it somehow or at least see execution order?

[1] http://bootdebian.blogspot.com/2006_...n_archive.html

[boban]

Originally Posted by K.Mandla Well, I tried it anyway and my boot time went from 28 seconds to 25.5 seconds on a dual 2.8Ghz P4 Xeon machine. No problems or errors as of yet. I'm going to see what happens when I try it on an older laptop ... Cheers!

Cool! I can't wait to try it by myslef (but I cannot do it right now, because I'm compiling OpenOffice, and I don't want to interrupt the process )

[K.Mandla]

Originally Posted by boban But how can I check/test that normal booting procedure ais parallel?

Good question. Personally, I just used the Timex method and got a slightly faster boot time. (Actually, 2.5 seconds on this machine is a huge improvement. Most tweaks have no effect at all.) Would bootchart give any indication of what was working at any given moment?

Originally Posted by boban I didn't see any boot speed improvement between Dapper and Edgy (but I didn't measure time either, so that is very subjective).

Really? I thought the Edgy startup was quite a bit faster than Dapper. Of course, I thought Dapper was faster than Breezy, too.

Originally Posted by boban And another thing - about single core cpus... I am a programmer myself and according to my previous experience adding concurrency to programs actually slows them [on single processor/core system] a bit. It's because additional overhead of concurrency control mechanisms and task switching. Parallel execution is only beneficial if some external delays are introduced, like waiting for ip address from dhcp server. So I assume that only some tasks are booting concurrent in Edgy boot-up process... Can I control it somehow or at least see execution order?

That's fairly complex stuff, and not anything I'm really proficient at. However, there is the sysv-rc-conf tool that allows you to arrange runlevels for some services. And again, bootchart might give you a clue when things are triggered and if they're actually being executed in an efficient manner.

Let me know what you come up with. I really do enjoy tweaking machines for speed, and anything that helps is something I like to try. Cheers!

[boban]

Originally Posted by K.Mandla Let me know what you come up with. I really do enjoy tweaking machines for speed, and anything that helps is something I like to try. Cheers!

I'll do it... And I'll answer your post in more details later (this might be tomorrow). Now I have to get back to work (yeah, I know it's Sunday, but I have no other choice right now )...

[boban]

Originally Posted by K.Mandla Would bootchart give any indication of what was working at any given moment?

I'll check that package soon... it looks cool

Originally Posted by K.Mandla sysv-rc-conf tool that allows you to arrange runlevels for some services. And again, bootchart might give you a clue when things are triggered and if they're actually being executed in an efficient manner.

I know this tool, but I thought it can only enable/disable services at certain runlevel (that is some control). But how could I control that one service has to be run before another within the same runlevel?

Originally Posted by K.Mandla Let me know what you come up with. I really do enjoy tweaking machines for speed, and anything that helps is something I like to try.

I have some issue with mounting disk during boot - I saw it just today (I don't reboot my system often). It hangs for about 15 seconds during boot on "mounting local filesystems" (or something like that). It drops even to console :/. But everything is working fine... (I'll dwell into that mater later).

My stats are:
* Ubuntu without concurrency - 56 sec
* Ubuntu with concurrency (shell) - 56 sec too
* Ubuntu with concurrency (startpar) - couldn't reboot my system after changing it (it started rebooting, then dropped to console - logged in as root! It looked like it was booted in 'single' mode)
* Gentoo without concurrency - 30 sek
* Gentoo with concurrency - 29 sek
* Windows Xp - 34 sek

When I resolve issue with mounting Ubuntu boot time should be shorter.

I'll optimise my boot services soon (haven't time to do that after switching to Edgy) and then post my new boot time

[K.Mandla]

Originally Posted by boban I know this tool, but I thought it can only enable/disable services at certain runlevel (that is some control). But how could I control that one service has to be run before another within the same runlevel?

That's a tough one. You'll probably have to hit Google to find an answer to that. Or maybe the Debian forums.

Originally Posted by boban I'll optimise my boot services soon (haven't time to do that after switching to Edgy) and then post my new boot time

I've put that tweak on a couple of machines and I usually see a slim cut in boot times, and still haven't run into any problems. I haven't used the startpar option though; I've been sticking with shell.

I used it on a straight Dapper Xubuntu build and saw a slight improvement, then reversed it only because I don't really care how long it takes to boot that machine (it's an always-on laptop).

I mostly have been putting it on Edgy Openbox builds which are already tuned for speed, but the results have been good. This GX260 (2.26Ghz, 512Mb, 10Gb 7200rpm) dropped three seconds on its start time, with no side effects that I've seen.

Cheers and thanks again!