Messages in this thread | | | Date | Mon, 07 Oct 2013 19:41:21 -0600 | From | David Ahern <> | Subject | Re: [RFC PATCH 00/50] tools/perf: Speed up the build system |
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On 10/7/13 10:41 AM, Ingo Molnar wrote: > > * David Ahern <dsahern@gmail.com> wrote: > >> I also noticed that the dwarf test is still run even with the NO_DWARF >> option passed in: >> >> [daahern@nxos-vdc-dev1 perf]$ make O=/tmp/junk LDFLAGS=-static >> NO_DWARF=1 -j 4 >> BUILD: Doing 'make -j16' parallel build >> >> Auto-detecting system features: >> >> ... backtrace: [ on ] >> ... dwarf: [ on ] >> ... fortify-source: [ on ] >> >> Note the dwarf test shows 'on'. > > Hm, yes. > > This is just the print-out though - the actual feature logic should still > follow the NO_DWARF=1 setting (modulo bugs). > > So I'm wondering, should we solve this by adding extra logic linking the > feature flags with their legacy names. It would get unwieldy rather > quickly I think.
yes.
> Another solution would be to introduce a new method to disable features, > via something like: > > make FEATURE_dwarf=0 > > Where the pattern would follow the auto-detected naming. This would > simplify the printout logic and would simplify the feature support / flags > decision tree as well. > > Furthermore, it would unify the various flags we have today, which is > rather mixed: for example there's NO_DWARF which is a name that shows > negated logic, but there's also HAVE_CPLUS_DEMANGLE_SUPPORT is is a name > with positive logic. We'd have one uniform naming scheme permeating the > whole build system.
The Kconfig series converts all of the NO_XXXXX to CONFIG_XXXXX. I'd like to see that because it mirrors kernel configs and is a stepping stone to kconf integration.
If the NO_XXXX takes precedence over the autoprobe detection then the user gets what is asked, so I guess we can leave it as is for now.
> > And that brings in your [K]config patches: which would make sense in that > context as well, as they'd allow the permanent configuration of features > with 3 states for each feature flag: > > off > auto-detect > on > > Your scheme I think makes a lot of sense on top of my bits. Packagers > would likely want to use a .config to build perf, most users would likely > be fine with a default of everything on auto-detect. Specialized users > would want to use their own .config's.
Yes. This series helps with the auto-probing config option. Jiri has done quite a bit in this direction as well. Once this set goes in I'll see if I can find some time to revisit the kconf stuff - unless Jiri beats me to it. We have been overlapping on a few features. ;-)
David
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