Tim Bird: change name to 'boot cache'

2011-01-25T19:48:14Z

change name to 'boot cache'

Tim Bird: moved Add fastboot parameter cache to kernel to Add boot cache to kernel: name was similar to other proposal

2011-01-25T19:47:32Z

moved Add fastboot parameter cache to kernel to Add boot cache to kernel: name was similar to other proposal

Tim Bird: add boot cache proposal

2011-01-25T19:19:57Z

add boot cache proposal

New page

; Summary: Add fastboot parameter cache to kernel

; Proposer: Tim Bird

== Description ==
This proposal would be the creation and mainlining of a fastboot
parameter cache for the Linux kernel.

The purpose of this cache would be to store values which are
detected in one boot of the Linux kernel, so they can be
quickly accessed and used on subsequent boots of the kernel,
to reduce kernel initialization time (specifically, to avoid
unneeded probing for non-changing hardware.)

The idea would be to provide an internal facility (API)
inside the kernel that drivers could use to query for
hardware parameters, prior to probing. If a value is found,
then the probe can be avoided. If not, then probing is
done as usual. It would be important to have a very unintrusive and
easy-to-use API for this.

The mechanism would need to support a method of persistently storing
the values for future kernel invocations (for example, by storing
them in persistent memory, in a device tree, passing them on the
kernel command line, or attaching them to the kernel boot image)

This can be seen as a generalization of the way probing/autodetection
is avoided by using a command line parameter for loops_per_jiffy.

Andrew Murray proposed this under the name "boot cache", in August, 2010
to the kernel mailing list.

== Related work ==
* See Andrew Murray's talk at ELC Europe 2010 - The Right Approach to Minimal Boot Times
** http://elinux.org/images/f/f7/RightApproachMinimalBootTimes.pdf
* See [[Preset LPJ]] for a description of how preset loops_per_jiffy works
* Andrew Murray's RFC and discussion on LKML:
** See https://lkml.org/lkml/2010/8/31/347

== Scope ==
The mechanism could probably be developed in 4 to 8 weeks. Mainlining it
might take 4 to 6 additional weeks.

== Contractor Candidates ==

== Comments ==

[[Category:Project proposals 2011]]

@@ Line 1: / Line 1: @@
-; Summary: Add fastboot parameter cache to kernel
+; Summary: Add boot cache to kernel
 ; Proposer: Tim Bird
 == Description ==
-This proposal would be the creation and mainlining of a fastboot
+This proposal would be the creation and mainlining of a boot
 parameter cache for the Linux kernel.

Add boot cache to kernel - Revision history

Tim Bird: change name to 'boot cache'

Tim Bird: moved Add fastboot parameter cache to kernel to Add boot cache to kernel: name was similar to other proposal

Tim Bird: add boot cache proposal