Re: [PATCH] perf tools: Do not show trace command if it's not compiled in

[Arnaldo Carvalho de Melo]

Em Tue, Jan 12, 2016 at 12:23:41PM +0100, Ingo Molnar escreveu:
> 
> * Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> 
> > The trace command still appears in help message when you
> > run simple 'perf' command.
> > 
> > It's because the generate-cmdlist.sh does not care about the
> > HAVE_LIBAUDIT_SUPPORT dependency of trace command and puts
> > it into generated common_cmds array.
> > 
> > Wrapping trace command under HAVE_LIBAUDIT_SUPPORT dependency,
> > which will exclude it from common_cmds array if HAVE_LIBAUDIT_SUPPORT
> > is not set.
> 
> Btw., would it make sense to still list them, but denote them as '[NOT BUILT IN]':

Yeah, just like we have:

  $ make NO_DWARF=1 O=/tmp/build/perf -C tools/perf/ install
  make: Entering directory '/home/git/linux/tools/perf'
    BUILD:   Doing 'make -j4' parallel build
  config/Makefile:328: DWARF support is off, BPF prologue is disabled
    SUBDIR   Documentation
    ASCIIDOC /tmp/build/perf/perf-diff.xml
    CC       /tmp/build/perf/util/abspath.o
  <SNIP>

  $ perf record -h vm build

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -B, --no-buildid        do not collect buildids in perf.data
      -N, --no-buildid-cache  do not update the buildid cache
          --vmlinux <file>    vmlinux pathname
                              (not built-in because NO_DWARF=1)

  $
 
>  The most commonly used perf commands are:
>    annotate        Read perf.data (created by perf record) and display annotated code
>    archive         Create archive with object files with build-ids found in perf.data file
>    bench           General framework for benchmark suites
>    buildid-cache   Manage build-id cache.
>    buildid-list    List the buildids in a perf.data file
>    config          Get and set variables in a configuration file.
>    data            Data file related processing
>    diff            Read perf.data files and display the differential profile
>    evlist          List the event names in a perf.data file
>    inject          Filter to augment the events stream with additional information
>    kmem            Tool to trace/measure kernel memory properties
>    kvm             Tool to trace/measure kvm guest os
>    list            List all symbolic event types
>    lock            Analyze lock events
>    mem             Profile memory accesses
>    record          Run a command and record its profile into perf.data
>    report          Read perf.data (created by perf record) and display the profile
>    sched           Tool to trace/measure scheduler properties (latencies)
>    script          Read perf.data (created by perf record) and display trace output
>    stat            Run a command and gather performance counter statistics
>    test            Runs sanity tests.
>    timechart       Tool to visualize total system behavior during a workload
>    top             System profiling tool.
>    probe           Define new dynamic tracepoints
>    trace           [NOT BUILT IN] strace inspired tool
> 
> ?
> 
> ... and print something informative if someone tries to use it:
> 
>   triton:~/tip> perf trace
>   Error: The 'trace' subcommand is not built into this version of perf.
>   Solution: You can enable it by rebuilding perf with all required libraries installed.
> 
> Instead of the rather misleading:
> 
>   triton:~/tip> perf trace
>   perf: 'trace' is not a perf-command. See 'perf --help'.
> 
> (Plus once we grow a 'perf upgrade' command, we can suggest rebuilding via that 
> route.)
> 
> Thanks,
> 
> 	Ingo