Bug 173696

Summary: udev inicialization is very slow
Product: [Fedora] Fedora Reporter: Adam Pribyl <covex>
Component: udevAssignee: Harald Hoyer <harald>
Status: CLOSED RAWHIDE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 4Keywords: FutureFeature
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Fixed In Version: Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2005-11-21 02:29:02 EST Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Description Adam Pribyl 2005-11-18 17:37:59 EST
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Description of problem:
Udev inicialization as it is in FC3-4 extremely slows down boot especialy on old hardware (Pentium 233), but the inicialition is the longest part even with the modern hardware.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. Use some old hardware
2. Reboot

Actual Results:  The udev start is taking tenth of seconds, the rest of boot is pretty fast compared to this.

Additional info:

This is only about to point to weak boot speed up point.

I am not very familiar with udev design, but I noticed that with self compiled, optimized kernel, inicialization is faster - this is because there is not so many modules to probe at boot.
Udev is fine for hotplugable devices, but its usage as is it now for "static" devices, that are in desktop computer initialzed on every boot it's not the best option.

The only way I can now thing of to improve its performace is to apply some kind of caching of modules (I do not mean readahead) that are applicable for machine and rest probe at background.
I mean - store at shutdown used modules, then probe only these at boot, then background.

Maybe there are some other options for udev startup enhancement (dev.d?).
Comment 1 Harald Hoyer 2005-11-21 02:29:02 EST
there were some improvements in recent udev versions... try rawhide and the
latest udev and kernel