[PATCH] Convert more passes to new dump framework

[Bernhard Reutner-Fischer]

On 30 August 2013 23:23:16 Teresa Johnson <tejohnson@google.com> wrote:
> On Fri, Aug 30, 2013 at 1:30 PM, Xinliang David Li <davidxl@google.com> wrote:
> > On Fri, Aug 30, 2013 at 12:51 PM, Teresa Johnson <tejohnson@google.com> 
> wrote:
> >> On Fri, Aug 30, 2013 at 9:27 AM, Xinliang David Li <davidxl@google.com> 
> wrote:
> >>> Except that in this form, the dump will be extremely large and not
> >>> suitable for very large applications.
> >>
> >> Yes. I did some measurements for both a fairly large source file that
> >> is heavily optimized with LIPO and for a simple toy example that has
> >> some inlining. For the large source file, the output from
> >> -fdump-ipa-inline=stderr was almost 100x the line count of the
> >> -fopt-info output. For the toy source file it was 43x. The size of the
> >> -details output was 250x and 100x, respectively. Which is untenable
> >> for a large app.
> >>
> >> The issue I am having here is that I want a more verbose message, not
> >> a more voluminous set of messages. Using either -fopt-info-all or
> >> -fdump-ipa-inline to provoke the more verbose inline message will give
> >> me a much greater volume of output.
> >>
> >> One compromise could be to emit the more verbose inliner message under
> >> a param (and a more concise "foo inlined into bar" by default with
> >> -fopt-info). Or we could do some variant of what David talks about
> >> below.
> >
> > something like --param=verbose-opt-info=1
>
> Yes. Richard, would this be acceptable for now?
>
> i.e. the inliner messages would be like:
>
> -fopt-info:
>    "test.c:8:3: note: foobar inlined into foo with call count 99999000"
> (the "with call count X" only when there is profile feedback)
>
> -fopt-info --param=verbose-opt-info=1:
>    "test.c:8:3: note: foobar/0 (99999000) inlined into foo/2 (1000)
> with call count 99999000 (via inline instance bar [3] (99999000))
> (again the call counts only emitted under profile feedback)

Assuming the [3] is order, please change that to match what the in liner 
uses, I.e. /3

Thanks
>
> >
> >
> >>
> >>> Besides, we might also want to
> >>> use the same machinery (dump_printf_loc etc) for dump file dumping.
> >>> The current behavior of using '-details' to turn on opt-info-all
> >>> messages for dump files are not desirable.
> >>
> >> Interestingly, this doesn't even work. When I do
> >> -fdump-ipa-inline-details=stderr (with my patch containing the inliner
> >> messages) I am not getting those inliner messages emitted to stderr.
> >> Even though in dumpfile.c "details" is set to (TDF_DETAILS |
> >> MSG_OPTIMIZED_LOCATIONS | MSG_MISSED_OPTIMIZATION | MSG_NOTE). I'm not
> >> sure why, but will need to debug this.
> >
> > It works for vectorizer pass.
>
> Ok, let me see what is going on - I just confirmed that it is not
> working for the loop unroller messages either.
>
> >
> >>
> >>> How about the following:
> >>>
> >>> 1) add a new dump_kind modifier so that when that modifier is
> >>> specified, the messages won't goto the alt_dumpfile (controlled by
> >>> -fopt-info), but only to primary dump file. With this, the inline
> >>> messages can be dumped via:
> >>>
> >>>    dump_printf_loc (OPT_OPTIMIZED_LOCATIONS | OPT_DUMP_FILE_ONLY, .....)
> >>
> >> (you mean (MSG_OPTIMIZED_LOCATIONS | OPT_DUMP_FILE_ONLY) )
> >>
> >
> > Yes.
> >
> >> Typically OR-ing together flags like this indicates dump under any of
> >> those conditions. But we could implement special handling for
> >> OPT_DUMP_FILE_ONLY, which in the above case would mean dump only to
> >> the primary dump file, and only under the other conditions specified
> >> in the flag (here under "-optimized")
> >>
> >>>
> >>>
> >>> 2) add more flags in -fdump- support:
> >>>
> >>>    -fdump-ipa-inline-opt   --> turn on opt-info messages only
> >>>    -fdump-ipa-inline-optall --> turn on opt-info-all messages
> >>
> >> According to the documentation (see the -fdump-tree- documentation on
> >> http://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html#Debugging-Options),
> >> the above are already supposed to be there (-optimized, -missed, -note
> >> and -optall). However, specifying any of these gives a warning like:
> >>    cc1: warning: ignoring unknown option ‘optimized’ in
> >> ‘-fdump-ipa-inline’ [enabled by default]
> >> Probably because none is listed in the dump_options[] array in dumpfile.c.
> >>
> >> However, I don't think there is currently a way to use -fdump- options
> >> and *only* get one of these, as much of the current dump output is
> >> emitted whenever there is a dump_file defined. Until everything is
> >> migrated to the new framework it may be difficult to get this to work.
> >>
> >>>    -fdump-tree-pre-ir --> turn on GIMPLE dump only
> >>>    -fdump-tree-pre-details --> turn on everything (ir, optall, trace)
> >>>
> >>> With this, developers can really just use
> >>>
> >>>
> >>> -fdump-ipa-inline-opt=stderr for inline messages.
> >>
> >> Yes, if we can figure out a good way to get this to work (i.e. only
> >> emit the optimized messages and not the rest of the dump messages).
> >> And unfortunately to get them all you need to specify
> >> "-fdump-ipa-all-optimized -fdump-tree-all-optimized
> >> -fdump-rtl-all-optimized" instead of just -fopt-info. Unless we can
> >> add -fdump-all-all-optimized.
> >
> > Having general support requires cleanup of all the old style  if
> > (dump_file) fprintf (dump_file, ...) instances to be:
> >
> >   if (dump_enabled_p ())
> >     dump_printf (dump_kind ....);
>
> Right. But that is going to be a big longer-term effort - grepping for
> dump_file in gcc/*.c gives about 6000 instances.
>
> >
> >
> > However, it might be easier to do this filtering for IR dump only (in
> > execute_function_dump) -- do not dump IR if any of the MSG_xxxx is
> > specified unless IR flag (a new flag) is also specified.
>
> Unfortunately there are a lot of messages that are not from
> execute_function_dump.
>
> Thanks,
> Teresa
>
> >
> > David
> >
> >
> >>
> >> Teresa
> >>
> >>>
> >>> thanks,
> >>>
> >>> David
> >>>
> >>> On Fri, Aug 30, 2013 at 1:30 AM, Richard Biener
> >>> <richard.guenther@gmail.com> wrote:
> >>>> On Thu, Aug 29, 2013 at 5:15 PM, Teresa Johnson <tejohnson@google.com> 
> wrote:
> >>>>> On Thu, Aug 29, 2013 at 3:04 AM, Richard Biener
> >>>>> <richard.guenther@gmail.com> wrote:
> >>>>>>>>> New patch below that removes this global variable, and also outputs
> >>>>>>>>> the node->symbol.order (in square brackets after the function name so
> >>>>>>>>> as to not clutter it). Inline messages with profile data look look:
> >>>>>>>>>
> >>>>>>>>> test.c:8:3: note: foobar [0] (99999000) inlined into foo [2] (1000)
> >>>>>>>>> with call count 99999000 (via inline instance bar [3] (99999000))
> >>>>>>>>
> >>>>>>>> Ick.  This looks both redundant and cluttered.  This is supposed to be
> >>>>>>>> understandable by GCC users, not only GCC developers.
> >>>>>>>
> >>>>>>> The main part that is only useful/understandable to gcc developers is
> >>>>>>> the node->symbol.order in square brackes, requested by Martin. One
> >>>>>>> possibility is that I could put that part under a param, disabled by
> >>>>>>> default. We have something similar on the google branches that emits
> >>>>>>> LIPO module info in the message, enabled via a param.
> >>>>>>
> >>>>>> But we have _dump files_ for that.  That's the developer-consumed
> >>>>>> form of opt-info.  -fopt-info is purely user sugar and for usual 
> translation
> >>>>>> units it shouldn't exceed a single terminal full of output.
> >>>>>
> >>>>> But as a developer I don't want to have to parse lots of dump files
> >>>>> for a summary of the major optimizations performed (e.g. inlining,
> >>>>> unrolling) for an application, unless I am diving into the reasons for
> >>>>> why or why not one of those optimizations occurred in a particular
> >>>>> location. I really do want a summary emitted to stderr so that it is
> >>>>> easily searchable/summarizable for the app as a whole.
> >>>>>
> >>>>> For example, some of the apps I am interested in have thousands of
> >>>>> input files, and trying to collect and parse dump files for each and
> >>>>> every one is overwhelming (it probably would be even if my input files
> >>>>> numbered in the hundreds). What has been very useful is having these
> >>>>> high level summary messages of inlines and unrolls emitted to stderr
> >>>>> by -fopt-info. Then it is easy to search and sort by hotness to get a
> >>>>> feel for things like what inlines are missing when moving to a new
> >>>>> compiler, or compiling a new version of the source, for example. Then
> >>>>> you know which files to focus on and collect dump files for.
> >>>>
> >>>> I thought we can direct dump files to stderr now?  So, just use
> >>>> -fdump-tree-all=stderr
> >>>>
> >>>> and grep its contents.
> >>>>
> >>>>>>
> >>>>>>> I'd argue that the other information (the profile counts, emitted only
> >>>>>>> when using -fprofile-use, and the inline call chains) are useful if
> >>>>>>> you want to understand whether and how critical inlines are occurring.
> >>>>>>> I think this is the type of information that users focused on
> >>>>>>> optimizations, as well as gcc developers, want when they use
> >>>>>>> -fopt-info. Otherwise it is difficult to make sense of the inline
> >>>>>>> information.
> >>>>>>
> >>>>>> Well, I doubt that inline information is interesting to users unless 
> we are
> >>>>>> able to aggressively filter it to what users are interested in.  
> Which IMHO
> >>>>>> isn't possible - users are interested in "I have not inlined this 
> even though
> >>>>>> inlining would severely improve performance" which would indicate a bug
> >>>>>> in the heuristics we can reliably detect and thus it wouldn't be there.
> >>>>>
> >>>>> I have interacted with users who are aware of optimizations such as
> >>>>> inlining and unrolling and want to look at that information to
> >>>>> diagnose performance differences when refactoring code or using a new
> >>>>> compiler version. I also think inlining (especially cross-module) is
> >>>>> one example of an optimization that is still being tuned, and user
> >>>>> reports of performance issues related to that have been useful.
> >>>>>
> >>>>> I really think that the two groups of people who will find -fopt-info
> >>>>> useful are gcc developers and savvy performance-hungry users. For the
> >>>>> former group the additional info is extremely useful. For the latter
> >>>>> group some of the extra information may not be required (although a
> >>>>> call count is useful for those using profile feedback), but IMO is not
> >>>>> unreasonable.
> >>>>
> >>>> well, your proposed output wrecks my 80x24 terminal already due to overly
> >>>> long lines.
> >>>>
> >>>> In the end we may up with a verbosity level for each sub-set of opt-info
> >>>> messages.  Ick.
> >>>>
> >>>> Richard.
> >>>>
> >>>>> Teresa
> >>>>>
> >>>>>
> >>>>> --
> >>>>> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
> >>
> >>
> >>
> >> --
> >> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
>
>
>
> --
> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413


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