On Fri, Aug 30, 2013 at 1:30 PM, Xinliang David Li <davi...@google.com> wrote: > On Fri, Aug 30, 2013 at 12:51 PM, Teresa Johnson <tejohn...@google.com> wrote: >> On Fri, Aug 30, 2013 at 9:27 AM, Xinliang David Li <davi...@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) > > >> >>> 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.guent...@gmail.com> wrote: >>>> On Thu, Aug 29, 2013 at 5:15 PM, Teresa Johnson <tejohn...@google.com> >>>> wrote: >>>>> On Thu, Aug 29, 2013 at 3:04 AM, Richard Biener >>>>> <richard.guent...@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 | tejohn...@google.com | 408-460-2413 >> >> >> >> -- >> Teresa Johnson | Software Engineer | tejohn...@google.com | 408-460-2413 -- Teresa Johnson | Software Engineer | tejohn...@google.com | 408-460-2413
