> -----Original Message----- > From: Thomas Monjalon <tho...@monjalon.net> > Sent: Tuesday, November 17, 2020 10:58 AM > To: Bruce Richardson <bruce.richard...@intel.com> > Cc: Juraj Linkeš <juraj.lin...@pantheon.tech>; Honnappa Nagarahalli > <honnappa.nagaraha...@arm.com>; Ruifeng Wang > <ruifeng.w...@arm.com>; Phil Yang <phil.y...@arm.com>; > vcchu...@amazon.com; Dharmik Thakkar <dharmik.thak...@arm.com>; > jerinjac...@gmail.com; hemant.agra...@nxp.com; Ajit Khaparde > (ajit.khapa...@broadcom.com) <ajit.khapa...@broadcom.com>; > ferruh.yi...@intel.com; dev@dpdk.org; david.march...@redhat.com; nd > <n...@arm.com> > Subject: Re: [dpdk-dev] [PATCH v12 01/14] build: alias default build as > generic > > 17/11/2020 10:15, Bruce Richardson: > > On Tue, Nov 17, 2020 at 08:49:45AM +0100, Thomas Monjalon wrote: > > > 17/11/2020 03:46, Honnappa Nagarahalli: > > > > <snip> > > > > > > > > > > > > > > 16/11/2020 17:16, Bruce Richardson: > > > > > > On Mon, Nov 16, 2020 at 03:50:31PM +0000, Juraj Linkeš wrote: > > > > > > > From: Thomas Monjalon <tho...@monjalon.net> > > > > > > > > 13/11/2020 15:31, Juraj Linkeš: > > > > > > > > > The current machine='default' build name is not > > > > > > > > > descriptive. The actual default build is > > > > > > > > > machine='native'. Add an alternative string which does > > > > > > > > > the same build and better describes what we're > > > > > building: > > > > > > > > > machine='generic'. Leave machine='default' for backwards > > > > > compatibility. > > > > > > > > > > > > > > > > What? > > > > > > > > > > > > > > > > "generic" means... nothing. > > > > > > > > > > > > > > > > > > > > > > An absence of anything means nothing. Generic means > > > > > > > "characteristic of > > > > > or relating to a class or group of things; not specific", which > > > > > is pretty much what we're looking for. > > > > > > > > > > > > > > > "default" should be the most common set of options to make > > > > > > > > a build work everywhere. > > > > > > > > > > > > > > What we want is a value of machine that would "be the most > > > > > > > common > > > > > set of options to make a build work everywhere" and using the > > > > > above definition of generic, it fits very well. > > > > > > > The reason I said the actual default build is > > > > > > > machine='native' is because > > > > > that's how the machine option is defined in meson_options.txt. > > > > > It follows from what default actually means - "a preselected > > > > > option adopted by a computer program or other mechanism when no > > > > > alternative is specified by the user or programmer". Default > > > > > then means no user input, which means machine='native', which means > the default build is the default build. > > > > > > > > > > > > > > What ""default" should mean" looks like an attempt at > > > > > > > redefining what > > > > > the word actually means and leads to confusion, in my > > > > > experience. Hence an attempt to remove the potential ambiguity. > > > > > > > > > > > > > > > > > > > I would tend to agree that "generic" is probably a better term > > > > > > than "default" for what we use it for here in the config. > > > > > > > > > > In the past, we had a different definition with make config. > > > > > I am just trying to be consistent. > > > > > Even with meson, default means "minimal CPU instructions". > > > > > > > > > > Example in devtools/test-meson-builds.sh: > > > > > "test compilation with minimal x86 instruction set" > > > > > is called build-x86-default. > > > > > > > > > > In config/meson.build: > > > > > " > > > > > machine type 'default' is special, it defaults to the per arch > > > > > agreed common minimal baseline needed for DPDK. > > > > > That might not be the most optimized, but the most portable > > > > > version while still being able to support the CPU features required > > > > > for > DPDK. > > > > > This can be bumped up by the DPDK project, but it can never be > > > > > an invariant like 'native' > > > > > " > > > > > > > > > > So, why this definition is called "generic" in meson Arm config? > > > > The explanation above is for a build type 'default'. Whereas meson by > default builds for build type 'native'. Also when you look at the > config/arm/meson.build the word 'default' was used where it was not related to > the build type default. It created lot of confusion. > > > > > > > > From the dictionary 'default' - "a preselected option adopted by a > computer program or other mechanism when no alternative is specified by the > user or programmer." But, if one had to do build of type default, they have to > mention -Dmachine=default. If nothing is mentioned, it is a build type > 'native', > which does not go along with the definition of 'default'. > > > > > > > > But for 'generic' - "characteristic of or relating to a class or group > > > > of things; > not specific". IMO, it better suits the explanation you have provided above. > So, > separating this machine type to 'generic' to cover the same definition makes > more sense. > > > > > > > > However, 'default' is still supported for backward compatibility. > > > > > > So? Are you going to change the DPDK definitions we had for years? > > > > > > > I think we should, or at least support "generic" alongside it. Using > > the term "default" for something that is not the default is confusing. > > It's also not a good description of what the result is, since it's a > > generic binary for the architecture, rather than a "default" one for the > architecture. > > OK in this case, please do the patch which changes it everywhere, not only for > Arm. We can change our names as long as it is explained and have some > consistency. >
Yes, I'll make a separate patchset for this. In this case the change also started out as arm specific and we made it arch agnostic over time.