Greetings from the free side / T'as le bonjour du libre !

Aller au contenu | Aller au menu | Aller à la recherche

vendredi 17 octobre 2008

24 seconds !

This is my new boot time, thanks to the instructions of Mandriva's kernel star, pterjan :-p. Thanks for having been so reactive.

If you didn't, you should read my previous entry about boot time. So, how did these 9 seconds (compared to 2009.0 without the fix, and 7 compared to 2008.1) disapeared ? Well, first, I'd tell you I'm not sure they're completely gone, because I felt that loging in was sensibly slower (more time until I have a wallpaper) but I have no numbers for this, as I only measured the boot time until gdm for 2008.1 and 2009.0. So maybe the "graphical desktop startup time" is a bit longer, but not 7 seconds longer, so I'm sure I won some time...

So where was the problem ? Well it seems that the usb-storage module is at fault. Yes. Again. Here is what fcrozat told us a few weeks ago in his article named "Improving boot time on a general Linux distribution, not an easy task" :

We also had reports of "udev takes forever" when people had usb storage devices plugged on their system. We did some tests and it was adding about 5s to boot, mostly because of "usb-storage" settle delay (which is 5s), when udev coldplug starts. To try to reduce this, we are now loading usb-storage module before udev is started, if an usb mass storage device is detected, to make sure the 5s "usb-storage" settle delay is done in parallel with udev. Average gain : 3s (there is still a penalty of about 2s when usb mass storage is plugged but we can't really do anything about it ATM).

From my lsinitrd output, pterjan could see that my initrd was loading the usb-storage module. I had no USB storage device connected, but it was nonetheless slowing me. In fact, it seems that an old buggy version of harddrake used to add instructions to load usb-storage in /etc/modprobe.conf. It's an old bug, but unluckily, if the command is already there, no tool will remove it for you. I saw today that my work laptop running 2008.1 has the same problem.

The solution was to remove the /sbin/modprobe usb_storage; command from my /etc/modprobe.conf , and to regenerate the initrd (which I had never done before - don't laugh). This was easy. It seems this module is only required to be in the initrd if your root (/) partition is on an USB storage device.

If you want to do the same, first make sure you have another kernel on which you'll be able to boot (it may be the case if you upgraded from 2008.1 like me). If not, backup your current initrd (you'll however need a live CD to restore it in case you're in trouble). Then, as root, call this command :

mkinitrd -f /boot/initrd-$(uname -r).img $(uname -r)

This will regenerate the initrd for the kernel version you're currently running. Then bootchart again. Then enjoy.

mardi 14 octobre 2008

What happened to my boot time, dude ?

Hum... Why did I lose 2 seconds in boot time ? 2008.1 booted in 31s, and 2009.0 boots in 33s.

Update : As asked by pterjan, here is the result of the lsinitrd command.

Update : running depmod didn't fix the problem.

mardi 30 septembre 2008

Mandriva on the boot time front

It's nice to see that Mandriva is working on shortening the boot time. Even if we're not at a 5 seconds boot (which, I agree with fcrozat, is unreal - what people should ask for is flawless resume instead), I've seen on some of his bootchart graphs a 10% speedup which is cool. As it's been a long time since I didn't use bootchart, and tried it again and benchmarked my Mandriva 2008.1/GNOME system, in case it's useful for someone.

Here it is: