[Bug 1488620] Re: [FFe] Add LZ4 support to initramfs-tools

[Steve Langasek]

This is a low-priority bug and has missed the window for 18.04.  I'm
nack'ing this for FFe.

The original request remains valid, so I'm resetting this to a non-FFe
bug rather than closing it.

** Summary changed:

- [FFe] Add LZ4 support to initramfs-tools
+ Add LZ4 support to initramfs-tools

** Description changed:

- Feature Freeze Justification
- ============================
- 
- Initramfs-tools uses gzip compression by default which served us well
- for quite some time but LZ4 offers way faster decompression while
- making a only slightly bigger initramfs files.
- 
- Having lz4 supported by initramfs-tools would allow users to opt-in for
- faster boot in Bionic from day 1.
- 
- On my old laptop the initramfs extraction time decreased from ~1.2s to ~0.24s:
- (with lz4)
- kernel: [    0.285692] Unpacking initramfs...
- kernel: [    0.518806] Freeing initrd memory: 65148K
- kernel: [    0.289731] Unpacking initramfs...
- kernel: [    0.522823] Freeing initrd memory: 65148K
- (with gzip)
- kernel: [    0.273748] Unpacking initramfs...
- kernel: [    1.490066] Freeing initrd memory: 57140K
- kernel: [    0.281729] Unpacking initramfs...
- kernel: [    1.498493] Freeing initrd memory: 57140K
- 
- Discussion on ubuntu-devel:
- https://lists.ubuntu.com/archives/ubuntu-devel/2018-March/040258.html
- 
- IMO the attached patch is minimally intrusive and it is safe to make
- this change even at this late hour of the release cycle.
- 
- I have uploaded the package to this PPA for testing the build:
- https://launchpad.net/~rbalint/+archive/ubuntu/scratch
- 
- I'm also using the updated package on my system.
- 
  Original Bug Text
  =================
  
  I found that I could enable LZ4 compression for initramfs on my vivid
  machine by installing liblz4-tool package, adding one line to
  mkinitramfs and installing a kernel compiled with CONFIG_CRYPTO_LZ4=y.
  
  Please include support for (legacy) LZ4.
  
  Attached patch includes changes made to the latest version (initramfs-
  tools_0.120ubuntu3).

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to initramfs-tools in Ubuntu.
https://bugs.launchpad.net/bugs/1488620

Title:
  Add LZ4 support to initramfs-tools

Status in initramfs-tools package in Ubuntu:
  New

Bug description:
  Original Bug Text
  =================

  I found that I could enable LZ4 compression for initramfs on my vivid
  machine by installing liblz4-tool package, adding one line to
  mkinitramfs and installing a kernel compiled with CONFIG_CRYPTO_LZ4=y.

  Please include support for (legacy) LZ4.

  Attached patch includes changes made to the latest version (initramfs-
  tools_0.120ubuntu3).

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/1488620/+subscriptions