RE: [OE-core][PATCH] bitbake.conf: Add resource vars to hash ignore list

[Peter Kjellerstedt <peter.kjellerstedt@axis.com>]

> -----Original Message-----
> From: openembedded-core@lists.openembedded.org <openembedded-
> core@lists.openembedded.org> On Behalf Of Richard Purdie
> Sent: den 22 augusti 2022 13:19
> To: Quentin Schulz <quentin.schulz@theobroma-systems.com>; Wes Lindauer
> <wesley.lindauer@gmail.com>; openembedded-core@lists.openembedded.org
> Subject: Re: [OE-core][PATCH] bitbake.conf: Add resource vars to hash
> ignore list
> 
> On Mon, 2022-08-22 at 11:28 +0200, Quentin Schulz wrote:
> > Hi Wes,
> >
> > On 8/22/22 06:59, Wes Lindauer wrote:
> > > It should not matter what xz/zstd parallelism and resource usage is set to
> > > when determining hash signatures. This allows sharing more sstate across
> > > host machines with different CPU configurations.
> > >
> >
> > It seems like it does matter in some ways, c.f.:
> > https://git.openembedded.org/openembedded-core/commit/?id=0296dc71c01d1b7953d74ef37d56429e2f4fcfab
> > and
> > https://git.openembedded.org/openembedded-core/commit/?id=e72c0b94554a9bc293844ec2bddb0c04ea19791d
> 
> As Quentin mentions, the value does matter. In particular, those
> compiled with a single thread differ to those with multiple threads. As
> such the proposed patch can't be accepted.
> 
> Cheers,
> 
> Richard

Isn't the problem of varying XZ_THREAD/ZSTD_THREAD vs taskhashes 
already taken care of by having:

XZ_THREADS ?= "${@oe.utils.cpu_count(at_least=2)}" 
XZ_THREADS[vardepvalue] = "1"
XZ_DEFAULTS ?= "--memlimit=${XZ_MEMLIMIT} --threads=${XZ_THREADS}" 
XZ_DEFAULTS[vardepsexclude] += "XZ_MEMLIMIT XZ_THREADS"
ZSTD_THREADS ?= "${@oe.utils.cpu_count(at_least=2)}" 
ZSTD_THREADS[vardepvalue] = "1"

in bitbake.conf.

//Peter