What happens during the "Waiting for UDev uevents to be processed"?

Laserpithium · 2010-07-19 09:58:59

Hello dear archers,

I have arch installed on my laptop, working great, I really love it.
Only one thing bother me and I would like to solve it: at boot time, the system waits for about 15s on the stage "Waiting for UDev uevents to be processed".

Is it normal? What is it doing exactly during this stage: loading modules?
I try to see in my logs but I can't find anything related to this. How can I know if there is not some kind of issue which make him takes so long ? How can I improve this ?

karol · 2010-07-19 10:19:15

15s is really long. It's <5s here.

> Is it normal?
Does it bother you that much to invest an hour or more to investigate and _maybe_ get the thing booting 10s faster?

> What is it doing exactly during this stage: loading modules?
Processing udev rules I think.

Last edited by karol (2010-07-19 10:24:44)

Laserpithium · 2010-07-19 10:31:14

karol wrote:

Does it bother you that much to invest an hour or more to investigate and _maybe_ get the thing booting 10s faster?

Yes !
I am definitely ready to play a few hours with the distro to save a 10s boot. Not really for the improved boot time, but for playing with the distro.

karol · 2010-07-19 10:37:26

Post the output of

ls /etc/X11/xorg.conf.d/

http://wiki.archlinux.org/index.php/Udev#Introduction
I think the more stuff you have, the longer it will take to configure.

Last edited by karol (2010-07-19 10:39:15)

Laserpithium · 2010-07-19 10:45:12

ls /etc/X11/xorg.conf.d/
10-evdev.conf  10-quirks.conf  10-synaptics.conf

But are you sure this is related to X ? Because that happens at the beginning of the boot process (not yet in run-level 3), far before any X related stuff unless I am mistaking.

karol · 2010-07-19 10:51:51

> But are you sure this is related to X ?
You mean the 'X11' part? We keep all those .conf files in one place, and it so happens to be an X11 subfolder. Yours is certainly not overcrowded.

tomk · 2010-07-19 11:33:34

Read /etc/rc.sysinit, look for references to uevents, find out what the related udevadm commands do.

karol · 2010-07-19 11:45:26

Google 'bootchart', maybe this will help you speed things up.

Inxsible · 2010-07-19 13:42:00

Funny, how the most obvious hasn't been mentioned yet.....or maybe the OP already has done this.

Have you backgrounded all the DAEMONS in your rc.conf?

That's the most easiest way of speeding up your boot time. The only thing that I don't background is syslog-ng

Last edited by Inxsible (2010-07-19 13:42:50)

karol · 2010-07-19 14:13:59

OP wrote about 15s _udev_: about 15s on the stage "Waiting for UDev uevents to be processed".

Ashren · 2010-07-19 14:21:03

Karol: How could the contents of /etc/X11/xorg.conf.d/ possibly be related to how long udev events takes to process?

Laserphitium: I've had a similar problem when using a Samsung DVD burner in combination with IDE HDD's, but it took 40+ seconds. What kind of HW setup do you have?

Inxsible: That wouldn't really help much with this particular problem since the Daemons run after Udev has finished processing.

bobdob · 2010-07-19 14:27:03

I had a problem before with udev taking a long time if I had a cd/dvd in my dvd drive. It doesn't happen anymore, but it might be something related to that.

karol · 2010-07-19 14:33:54

@ Ashren
udev is for setting the devices - like /dev/dsp, right?
I honestly don't know whether evdev & automounting are for X only. I should have checked it first but I'm lazy and stupid so I said what I said.
Sorry.
I'll finish my coffee and go to bed.

cesura · 2010-07-19 16:06:37

karol wrote:

OP wrote about 15s _udev_: about 15s on the stage "Waiting for UDev uevents to be processed".

Ashren wrote:

Inxsible: That wouldn't really help much with this particular problem since the Daemons run after Udev has finished processing.

If you can eliminate, say, 12 seconds by backgrouning all of your daemons, then that's a 12 second faster boot, so Udev's long startup wouldn't really matter. Not really a solution, but it would help until you are actually able to solve it.

Runiq · 2010-07-19 16:47:57

Two shots in the dark:
- Does your laptop have an Optiarc optical drive?
- Do you have a large external HDD plugged in at boot?

Laserpithium · 2010-07-20 08:34:18

Thank you for all your answers.

Well, according to the man page and rc.sysinit, udevadm command in the rc.sysinit script does:

/sbin/udevadm settle
/sbin/udevadm control --property=STARTUP=

I assume this is the settle command which takes time.
But how can I list the uevents in the queue the udevadm settle command is waiting for ? If possible, with the delay of treatment of each of these uevents during the boot...
I have nothing related to this in my logs.

Regarding my hardware, I have one toshiba laptop P300-220 with two internal hard drives (and many partitions on them). But no external drive.

Last edited by Laserpithium (2010-07-20 08:35:36)

karol · 2010-07-20 08:36:24

I've heard about a re-wirte that executes those things in parallel so it takes only 0.5 second - but the code is not open atm.

Edit: Some fresh things going on with the udev package: http://bugs.archlinux.org/task/20107

Last edited by karol (2010-07-20 08:41:26)

Arch Linux

#1 2010-07-19 09:58:59

What happens during the "Waiting for UDev uevents to be processed"?

#2 2010-07-19 10:19:15

Re: What happens during the "Waiting for UDev uevents to be processed"?

#3 2010-07-19 10:31:14

Re: What happens during the "Waiting for UDev uevents to be processed"?

#4 2010-07-19 10:37:26

Re: What happens during the "Waiting for UDev uevents to be processed"?

#5 2010-07-19 10:45:12

Re: What happens during the "Waiting for UDev uevents to be processed"?

#6 2010-07-19 10:51:51

Re: What happens during the "Waiting for UDev uevents to be processed"?

#7 2010-07-19 11:33:34

Re: What happens during the "Waiting for UDev uevents to be processed"?

#8 2010-07-19 11:45:26

Re: What happens during the "Waiting for UDev uevents to be processed"?

#9 2010-07-19 13:42:00

Re: What happens during the "Waiting for UDev uevents to be processed"?

#10 2010-07-19 14:13:59

Re: What happens during the "Waiting for UDev uevents to be processed"?

#11 2010-07-19 14:21:03

Re: What happens during the "Waiting for UDev uevents to be processed"?

#12 2010-07-19 14:27:03

Re: What happens during the "Waiting for UDev uevents to be processed"?

#13 2010-07-19 14:33:54

Re: What happens during the "Waiting for UDev uevents to be processed"?

#14 2010-07-19 16:06:37

Re: What happens during the "Waiting for UDev uevents to be processed"?

#15 2010-07-19 16:47:57

Re: What happens during the "Waiting for UDev uevents to be processed"?

#16 2010-07-20 08:34:18

Re: What happens during the "Waiting for UDev uevents to be processed"?

#17 2010-07-20 08:36:24

Re: What happens during the "Waiting for UDev uevents to be processed"?

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