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Author Topic: Is possible to get rid of udevd errors at boot?  (Read 5288 times)

Offline julcar

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Is possible to get rid of udevd errors at boot?
« on: March 02, 2020, 01:24:58 AM »
I am testing Tinycore in a Limbo (qemu) virtual machine on my android tablet, it is a bit slow but works, however when booting there is a lot of udevd related messages showed in screen while loading the system, and in fact every message takes its time to be printed and makes even slower the system loading, needless to say that older versions of tinycore (tested 4.4.7) almost doesn't show these messages and load faster than newer ones.

The messages are something like this:

Code: [Select]
udevd[122]: timeout: killing '/sbin/modprobe blabla
udevd[122]: '/sbin/modprobe -bv blabla [202] terminated by signal 9 (Killed)

Maybe digging to find the root of the problem could fix it, but right now I am clueless...

Thanks guys.

Offline andyj

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Offline Rich

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Re: Is possible to get rid of udevd errors at boot?
« Reply #2 on: March 02, 2020, 06:14:35 AM »
Hi julcar
... and in fact every message takes its time to be printed and makes even slower the system loading, ...
It's not each message taking its time to be printed that's slowing things down. It's likely something is using so much CPU time
it's slowing down the printing of messages, as well as every other process competing for time.

... The messages are something like this:

Code: [Select]
udevd[122]: timeout: killing '/sbin/modprobe blabla
udevd[122]: '/sbin/modprobe -bv blabla [202] terminated by signal 9 (Killed)
...
The  blabla  kernel module is known to be a source of trouble, so you should blacklist it. I also recommend running:
Code: [Select]
dmesg > dmesg.txtThen attach  dmesg.txt  to your next post.

Offline julcar

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Re: Is possible to get rid of udevd errors at boot?
« Reply #3 on: March 02, 2020, 10:38:40 PM »
here is the dmesg attached, surprisingly there is no mention about the countless messages at boot

Offline julcar

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Re: Is possible to get rid of udevd errors at boot?
« Reply #4 on: March 02, 2020, 11:19:35 PM »
Also here I recorded a small video to show the messages appearing in screen and slowing down the boot (the video itself lasts 3 minutes, the whole boot takes much longer)

https://www.facebook.com/julio.carchi.9/videos/2811331228920619/

Offline andyj

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Re: Is possible to get rid of udevd errors at boot?
« Reply #5 on: March 03, 2020, 05:19:40 AM »
Have you tried adding this to your kernel command line yet?

Code: [Select]
udev.children-max=24
If so, did it have any effect?

Offline Rich

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Re: Is possible to get rid of udevd errors at boot?
« Reply #6 on: March 03, 2020, 06:39:56 AM »
Hi julcar
I don't know whats going on, but it looks like it's having trouble finding your hardware. In some cases  dmesg  says it exists, like:
Code: [Select]
pci 0000:00:02.0: [1234:1111] type 00 class 0x030000and in some cases, it doesn't even show up in  dmesg , like  pcspkr  or  LNXSYBUS.

Offline julcar

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Re: Is possible to get rid of udevd errors at boot?
« Reply #7 on: March 03, 2020, 11:40:27 AM »
here is a screenshot of the lsmod command output after completing the boot process, seems a bit short for me

Offline julcar

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Re: Is possible to get rid of udevd errors at boot?
« Reply #8 on: March 03, 2020, 11:42:06 AM »
Have you tried adding this to your kernel command line yet?

Code: [Select]
udev.children-max=24
If so, did it have any effect?

no remarkable effect

Offline andyj

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Re: Is possible to get rid of udevd errors at boot?
« Reply #9 on: March 03, 2020, 01:45:09 PM »
Your VM has 64 MB of RAM. Try udev.children-max with a lower number. 6, or even 4. Or give your VM a little more RAM. There's not a lot of headroom.

Offline Rich

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Re: Is possible to get rid of udevd errors at boot?
« Reply #10 on: March 03, 2020, 01:50:08 PM »
Hi julcar
Your VM has 64 MB of RAM. Try udev.children-max with a lower number. 6, or even 4. Or give your VM a little more RAM. There's not a lot of headroom.
I misread the value in dmseg as 650 Meg. Definitely increase the amount of memory.

Offline julcar

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Re: Is possible to get rid of udevd errors at boot?
« Reply #11 on: March 03, 2020, 10:33:05 PM »
Your VM has 64 MB of RAM. Try udev.children-max with a lower number. 6, or even 4. Or give your VM a little more RAM. There's not a lot of headroom.

Tweaking the number to 3 or 2 makes some difference, I think this kind of info should be accessible somewhere to people who needs to install TinyCore into VM's with low resources...

by the way, which is the lowest amount of RAM that could boot an usable setup of Core? (no graphic interface), more RAM is not an option for me because my device has only 512 mb free for apps, and this VM is meant to run as service in background...


Offline julcar

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Re: Is possible to get rid of udevd errors at boot?
« Reply #12 on: March 03, 2020, 11:18:02 PM »
Answering to myself, in this article it states about the minimum RAM requirements for TinyCore, as small as 46 mb and recommended 64 mb.

Offline Rich

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Re: Is possible to get rid of udevd errors at boot?
« Reply #13 on: March 04, 2020, 06:43:11 AM »
Hi julcar
Answering to myself, in this article it states about the minimum RAM requirements for TinyCore, as small as 46 mb and recommended 64 mb.
That information is dated. It says the size of the current version of Core is 9 MB. It's 13 MB. For Tinycore it says 15 MB. It's 18 MB.

... older versions of tinycore (tested 4.4.7) almost doesn't show these messages and load faster than newer ones. ...
Jumping 6 releases from TC4 to TC10 or TC11 a lot has changed.

The kernel (vmLinuz) has grown from ~2.5 MB to ~4.3 MB.
The initrd (core.gz) has grown from ~5.3 MB to ~9.1 MB.
The newer extension likely also have larger memory requirements.

Try bumping up your memory to 96 MB to determine whether this is an insufficient memory issue or whether something else
is going on here.

Offline julcar

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Re: Is possible to get rid of udevd errors at boot?
« Reply #14 on: March 25, 2020, 11:11:16 PM »
Well, I could mark this as solved, finally after severals "try and error" I found the perfect config for my VM, I was not able to use any newer version than 4.7.7 (though 5.3 works also sometimes) with this append line:

Code: [Select]
quiet noswap nozswap noutc norestore noapic udev.children-max=3 tce=sda1 opt=sda1 home=sda1 swapfile=sda1

Especially the udev.children-max=3 reduced the countless udevd errors to just one, and setting it to 2 lets me to boot with only 48 MB of RAM, again I suggest to site admins to post this info anywhere on the wiki, because out there could be many users struggling with low-resources virtual machines, and TinyCore fits perfectly with this profile.