On Tue, Oct 15, 2013 at 3:39 PM, Teresa Johnson <tejohn...@google.com> wrote: > On Tue, Oct 15, 2013 at 2:57 PM, Jan Hubicka <hubi...@ucw.cz> wrote: >>> On Tue, Oct 15, 2013 at 2:03 PM, Jan Hubicka <hubi...@ucw.cz> wrote: >>> >> Yes, that would work. So let's discard this patch because the fix for >>> >> comdat can also fix this problem. >>> > >>> > Unforutnately ipa-profile-estimate is an IPA pass and as such it does >>> > not have access to profile_status_to_function. >>> >>> I see. I was coding that up today but hadn't tested it yet. >>> >>> > You can probably just factor this out into a function that can be called >>> > and for normal FDO we call it where the loop stis now and for auto-FDO we >>> > can >>> > probably have another invocation from before early passes where auto-FDO >>> > is collected. >>> >>> Ok, let's go with that approach for now. It won't address the 0 count >>> COMDAT calling another 0 count COMDAT problem, but I will probably >>> just find a way to deal with this when inlining. >> >> You can still propagate, since tree-profile is an simple-ipa pass. > > Ok, I think I will leave that for the second patch, since I need to do > some testing on the effects - i.e. the propagation I had in mind would > make any 0-count routine called by a routine that was dropped to > guessed to also be dropped to guessed (and no longer unlikely). It may > be too aggressive, I need to check. > >>> >>> >> >>> + if (node->count) >>> >> >>> + continue; >>> > Also here we should sum the counts and consider function non unlikely >>> > executed >>> > in the same way as probably_never_executed does. >>> >>> I assume you mean by doing the same comparison to the number of >>> profile->runs. Yes, this makes sense. >> >> Yes. >>> >>> > >>> > I can prepare updated patch, but i am currently travelling, so i would not >>> > be disapointed if you beat me ;) >>> >>> I'm working on it, and I think based on Dehao's needs I am going to >>> split up the patch into two phases, the one that does just the part >>> you had sent a patch for (making sure 0 count routines with non-zero >>> calls are marked guessed and have their node frequency set >>> appropriately), and a subsequent one to do the count application when >>> we inline a 0-count routine into a non-zero callsite. I'll shoot for >>> getting this ready by tomorrow. >>> >>> BTW, in your original patch you are checking for both e->count or >>> cgraph_maybe_hot_edge_p(e), but AFAICT the call to >>> cgraph_maybe_hot_edge_p will never return true when e->count is zero. >>> When there is a profile it will return false via maybe_hot_count_p >>> since e->count == 0. When there is no profile it will return false >>> when the callee has NODE_FREQUENCY_UNLIKELY_EXECUTED. So I think just >>> checking for e->count >0 is sufficient here. >> >> I think I was checking caller count here (that is read) and the code >> was supposed to make functoin with hot caller to be hot... > > The code in your patch was just checking the edge count, not the > caller count. cgraph_maybe_hot_edge_p also doesn't check the caller > count, just the edge count. Do we want to make all functions with hot > callers also be hot, even when the edge count is not hot? This may be > to aggressive. I was simply going to make the code check e->count.
Here is the patch from Honza, that I revised based on discussions and testing. Once this related patch goes in, I can change the check against the profile_info->runs that hardcodes the threshold with the new parameter proposed for probably_never_executed there: http://gcc.gnu.org/ml/gcc-patches/2013-10/msg00743.html Bootstrapped and tested on x86_64-unknown-linux-gnu. Ok for trunk? Thanks, Teresa 2013-10-16 Jan Hubicka <j...@suse.cz> Teresa Johnson <tejohn...@google.com> * predict.c (handle_missing_profiles): New function. (counts_to_freqs): Don't overwrite estimated frequencies when function has no profile counts. * predict.h (handle_missing_profiles): Declare. * tree-profile.c (tree_profiling): Invoke handle_missing_profiles. Index: predict.c =================================================================== --- predict.c (revision 203633) +++ predict.c (working copy) @@ -2742,6 +2742,39 @@ estimate_loops (void) BITMAP_FREE (tovisit); } +void +handle_missing_profiles (void) +{ + struct cgraph_node *node; + /* See if 0 count function has non-0 count callers. In this case we + lost some profile. Drop its function profile to PROFILE_GUESSED. */ + FOR_EACH_DEFINED_FUNCTION (node) + { + struct cgraph_edge *e; + gcov_type call_count = 0; + struct function *fn = DECL_STRUCT_FUNCTION (node->symbol.decl); + if (node->count) + continue; + for (e = node->callers; e; e = e->next_caller) + call_count += e->count; + if (call_count + && fn && fn->cfg + && (call_count * 4 >= profile_info->runs)) + { + bool maybe_hot = maybe_hot_count_p (NULL, call_count); + if (dump_file) + fprintf (dump_file, + "Dropping 0 profile for %s/%i. %s based on calls.\n", + cgraph_node_name (node), node->symbol.order, + maybe_hot ? "Function is hot" : "Function is normal"); + profile_status_for_function (fn) + = (flag_guess_branch_prob ? PROFILE_GUESSED : PROFILE_ABSENT); + node->frequency + = maybe_hot ? NODE_FREQUENCY_HOT : NODE_FREQUENCY_NORMAL; + } + } +} + /* Convert counts measured by profile driven feedback to frequencies. Return nonzero iff there was any nonzero execution count. */ @@ -2751,6 +2784,9 @@ counts_to_freqs (void) gcov_type count_max, true_count_max = 0; basic_block bb; + if (!ENTRY_BLOCK_PTR->count) + return 0; + FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb) true_count_max = MAX (bb->count, true_count_max); Index: predict.h =================================================================== --- predict.h (revision 203633) +++ predict.h (working copy) @@ -37,6 +37,7 @@ enum prediction extern void predict_insn_def (rtx, enum br_predictor, enum prediction); extern int counts_to_freqs (void); +extern void handle_missing_profiles (void); extern void estimate_bb_frequencies (bool); extern const char *predictor_name (enum br_predictor); extern tree build_predict_expr (enum br_predictor, enum prediction); Index: tree-profile.c =================================================================== --- tree-profile.c (revision 203633) +++ tree-profile.c (working copy) @@ -607,6 +607,8 @@ tree_profiling (void) pop_cfun (); } + handle_missing_profiles (); + del_node_map (); return 0; } > > Teresa > >> >> Honza >>> >>> Thanks, >>> Teresa >>> >>> > >>> > Honza >>> >>> >>> >>> -- >>> 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
