Messages in this thread | | | Date | Tue, 26 Nov 2013 19:03:33 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] perf: Move fs.* to generic lib/lk/ |
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* Borislav Petkov <bp@alien8.de> wrote:
> On Fri, Nov 22, 2013 at 04:54:25PM +0100, Ingo Molnar wrote: > > comet:~/tip/tools/perf> ls util/*.h > > util/annotate.h util/data.h util/fs.h util/parse-events-bison.h util/probe-event.h util/sort.h util/thread.h util/values.h > > util/build-id.h util/debug.h util/header.h util/parse-events-flex.h util/probe-finder.h util/stat.h util/thread_map.h util/vdso.h > > util/cache.h util/dso.h util/help.h util/parse-events.h util/pstack.h util/strbuf.h util/tool.h util/xyarray.h > > util/callchain.h util/dwarf-aux.h util/hist.h util/parse-options.h util/quote.h util/strfilter.h util/top.h > > util/cgroup.h util/event.h util/intlist.h util/perf_regs.h util/rblist.h util/strlist.h util/trace-event.h > > util/color.h util/evlist.h util/levenshtein.h util/pmu-bison.h util/run-command.h util/svghelper.h util/types.h > > util/comm.h util/evsel.h util/machine.h util/pmu-flex.h util/session.h util/symbol.h util/unwind.h > > util/cpumap.h util/exec_cmd.h util/map.h util/pmu.h util/sigchain.h util/target.h util/util.h > > > > That is pretty healty granularity IMO. > > > > Do we want a separate directory for each one? > > For each single one of them? This would be insane.
Not necessarily, if the number goes up - obviously then we'd also want to add some second directory structure to organize them into broad categories or so.
> > I don't see a big problem with doing that, but it could be kept in > > tools/lib/util/ or tools/lib/core/ as well, > > That's much better :) > > > _as long as they are not lumped together > > Why not a single .a?
Unnecessarily longer build time.
> > That also means that these bits shouldn't really be librarized in > > the classical sense into a single .a and linked into whatever tool > > uses it, but should be used individually as singular targets with > > clean .h interfaces to utilize them topically. > > Yeah, but why?
If a tool uses just a handful of these (hopefully quickly increasing number of) facilities then it should not be burdened by building it all.
> > That also means that utilities won't run into any dependency > > problems, and the build will be faster as well as it all will be a > > single dependency graph within a single make session. > > That's maybe the only half-reason for not lumping them together I've > read so far. I say half-reason because the preprocessor already will > include only stuff it needs. And if that were a problem, glibc > would've been multiple libs too.
The preprocessor does nothing with the .a - eliminating extra stuff from the .a is a link time step, and that means the whole .a will be built first ... just to throw away bits of it.
( Also, arguably, from a sw design POV glibc should probably have been multiple libs, but that's water down the bridge. No need to repeat/clone such mistakes though. )
Thanks,
Ingo
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