On Fri, Aug 30, 2013 at 9:51 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.
I think we will never reach the state where the dumping is exactly what each developer wants (because their wants will differ). Developers can easily post-process the stderr output with piping through grep. Richard. > 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. > >> 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. > >> 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) ) > > 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. > > 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
