Hi, sorry for the delay. I hope it's still possible to consider this
proposal for this year.

Caching of information on udev

; Summary: Caching device information on udev

; Proposer: Lucas De Marchi (lucas.demar...@profusion.mobi)

== Description ==
Currently udev is the most widely used device manager on Linux. It is
responsible for managing
the /dev entries, and provides several useful actions to be run on
specific occasions.

Right now udev does device discovery and setup on every boot. But
usually this is not needed, especially on embedded devices where the
hardware will not change over time. One major point of
improvement then in order to speed boot now is to cache the
information used by udev, and providing a way of verifying if this
cache is still valid or if it needs to be re-done.

Udev has several builtin handlers to address changes in the system, as
reported by the kernel: load modules, find firmware, apply rules to
new devices, etc. The purpose of this project is to add the necessary
infrastructure in udev so these builtin handlers can ask for caching
the information they need and re-play them on next boot. This
infrastructure will be evaluated by applying it to module loading:
instead of probing the bus on every boot to decide we need to load a
certain module, we can load it nonetheless because previous boots
needed them. Later on boot sequence we can verify if they were indeed
needed and cache for next boot.

This idea has already been discussed with the udev upstream, and
they want to see how performance is improved by having such a cache.
The intention is to implement this cache and create benchmarks for
embedded devices, where usually the hardware is not changed between
reboots.

== Related work ==
* http://en.wikipedia.org/wiki/Udev

== Scope ==
 # Implementation: 2 weeks
 # Benchmark creation: 1 week
 # Adapt to community feedback, tests and upstream: 2 weeks

== Comments ==



--
Lucas De Marchi
_______________________________________________
Celinux-dev mailing list
Celinux-dev@lists.celinuxforum.org
https://lists.celinuxforum.org/mailman/listinfo/celinux-dev

Reply via email to