[PATCH] UBUNTU: [Config] Switch from DECOMP_SINGLE to DECOMP_MULTI_PERCPU

[Dimitri John Ledkov]

Hi,

On Mon, 29 Aug 2022 at 08:07, Andrea Righi <andrea.righi at canonical.com> wrote:
>
> On Fri, Aug 26, 2022 at 03:31:28PM +0100, Dimitri John Ledkov wrote:
> > BugLink: https://bugs.launchpad.net/bugs/1980861
> >
> > Overall MULTI_PERCPU has similar or better performance on the wide
> > range of instance types and squashfs filesystems.
> >
> > Signed-off-by: Dimitri John Ledkov <dimitri.ledkov at canonical.com>
>
> How about memory usage? Have we done any test to measure the memory
> footprint after this change?
>
> Considering that snap is using squashfs and snap is pretty much
> everywhere nowdays, I was wondering if this change may trigger potential
> OOM conditions in some small cloud instances that we support (i.e., on
> AWS) or small systems in general.
>

We have tested this change on a variety of instance types, in a
variety of clouds. Including tiny, regular and large instance types.

Generally, there is some small increase in memory usage, but we were
unable to trigger OOM conditions. Specifically, because small RAM
systems typically also have small CPU core count as well, resulting in
very negligible positive or negative impact on them.


> Thanks,
> -Andrea
>
> > ---
> >  debian.master/config/annotations          | 5 +++--
> >  debian.master/config/config.common.ubuntu | 4 ++--
> >  2 files changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/debian.master/config/annotations b/debian.master/config/annotations
> > index 2e96b8206b..c28ef8ab47 100644
> > --- a/debian.master/config/annotations
> > +++ b/debian.master/config/annotations
> > @@ -10848,9 +10848,10 @@ CONFIG_SQUASHFS_4K_DEVBLK_SIZE                  note<non-default block size>
> >  CONFIG_SQUASHFS                                 mark<ENFORCED> note<LP: #1593134>
> >
> >  # Menu: File systems >> Miscellaneous filesystems >> SquashFS 4.0 - Squashed file system support >> Decompressor parallelisation options
> > -CONFIG_SQUASHFS_DECOMP_SINGLE                   policy<{'amd64': 'y', 'arm64': 'y', 'armhf': 'y', 'ppc64el': 'y', 'riscv64': 'y', 's390x': 'y'}>
> > +CONFIG_SQUASHFS_DECOMP_SINGLE                   policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'ppc64el': 'n', 'riscv64': 'n', 's390x': 'n'}>
> >  CONFIG_SQUASHFS_DECOMP_MULTI                    policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'ppc64el': 'n', 'riscv64': 'n', 's390x': 'n'}>
> > -CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU             policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'ppc64el': 'n', 'riscv64': 'n', 's390x': 'n'}>
> > +CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU             policy<{'amd64': 'y', 'arm64': 'y', 'armhf': 'y', 'ppc64el': 'y', 'riscv64': 'y', 's390x': 'y'}>
> > +CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU             mark<ENFORCED> note<LP: #1980861>
> >
> >  # Menu: File systems >> Miscellaneous filesystems >> SquashFS 4.0 - Squashed file system support >> File decompression options
> >  CONFIG_SQUASHFS_FILE_CACHE                      policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'ppc64el': 'n', 'riscv64': 'n', 's390x': 'n'}>
> > diff --git a/debian.master/config/config.common.ubuntu b/debian.master/config/config.common.ubuntu
> > index c52f519868..cb3fc66a03 100644
> > --- a/debian.master/config/config.common.ubuntu
> > +++ b/debian.master/config/config.common.ubuntu
> > @@ -11188,8 +11188,8 @@ CONFIG_SPS30_SERIAL=m
> >  CONFIG_SQUASHFS=y
> >  # CONFIG_SQUASHFS_4K_DEVBLK_SIZE is not set
> >  # CONFIG_SQUASHFS_DECOMP_MULTI is not set
> > -# CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU is not set
> > -CONFIG_SQUASHFS_DECOMP_SINGLE=y
> > +CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU=y
> > +# CONFIG_SQUASHFS_DECOMP_SINGLE is not set
> >  # CONFIG_SQUASHFS_EMBEDDED is not set
> >  # CONFIG_SQUASHFS_FILE_CACHE is not set
> >  CONFIG_SQUASHFS_FILE_DIRECT=y
> > --
> > 2.34.1
> >
> >
> > --
> > kernel-team mailing list
> > kernel-team at lists.ubuntu.com
> > https://lists.ubuntu.com/mailman/listinfo/kernel-team



-- 
okurrr,

Dimitri