Hi,
this patch implements -fprofile-consistency-report that is useful to get an
statistic about what pass are major offenders in keeping profile up-to-date.
For example the following is output for combine.c
Pass: fnsplit (after pass) mismatched in: +16 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: fnsplit (after TODO) mismatched in: -16 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: inline (after pass) mismatched in: +197 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: inline (after TODO) mismatched in: -209 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: ccp (after TODO) mismatched in: +8 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: vrp (after pass) mismatched in: +191 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: vrp (after TODO) mismatched in: +25 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: dce (after TODO) mismatched in: -19 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: cdce (after pass) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: cselim (after pass) mismatched in: +1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: ifcombine (after TODO) mismatched in: +1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: phiopt (after pass) mismatched in: -2 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: ch (after pass) mismatched in: +2 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: ch (after TODO) mismatched in: +1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: dom (after pass) mismatched in: +89 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: dom (after TODO) mismatched in: -3 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: phicprop (after TODO) mismatched in: -6 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: dce (after TODO) mismatched in: -2 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: copyprop (after TODO) mismatched in: -17 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: unswitch (after pass) mismatched in: +7 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: unswitch (after TODO) mismatched in: +19 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: cunroll (after pass) mismatched in: +10 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: vrp (after pass) mismatched in: +18 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: vrp (after TODO) mismatched in: -8 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: dom (after pass) mismatched in: +14 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: dom (after TODO) mismatched in: +4 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: phicprop (after TODO) mismatched in: +1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: cddce (after TODO) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: expand (after pass) mismatched in: +435 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: jump (after pass) mismatched in: +6 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: cse1 (after pass) mismatched in: +1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: cprop (after pass) mismatched in: -8 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: rtl pre (after pass) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: cse_local (after pass) mismatched in: -7 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: ce1 (after pass) mismatched in: +5 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: loop2_init (after pass) mismatched in: +1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: loop2_done (after pass) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: reload (after pass) mismatched in: -4 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: gcse2 (after pass) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: split2 (after pass) mismatched in: +1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: pro_and_epilogue (after pass) mismatched in: +4 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: dse2 (after pass) mismatched in: -2 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: jump2 (after pass) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: ce3 (after pass) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: bbro (after pass) mismatched in: -6 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
Pass: compgotos (after pass) mismatched in: -1 (freqs) +0
(counts); michmatched out: +0 (freqs) +0 (counts)
As a quick explanation, inliner is recomputing frequencies as part of TODO, so
the divergence. VRP and DOM breaks a lot of probabilities by jump threading
where the original estimate was inconsistent (it would make sense to do some of
jump threading prior profile estimate).
Expansion obviously needs a lot of TLC, not only in switch expansion that
is currently all wrong and quite commonly excercised in combine.c
Regtested/bootstrapped x86_64-linux. If there are no complains I will commit
the patch tomorrow.
Honza
* doc/invoke.texi (-fprofile-consistency-report): Document.
* common.opt (fprofile-consistency-report): New.
* toplev.h (dump_profile_consistency_report): Declare.
* toplev.c (finalize): Call dump_profile_consistency_report.
* passes.c (profile_record): New global var.
(check_profile_consistency): New function.
(dump_profile_consistency_report): New function.
(execute_one_ipa_transform_pass): Call check_profile_consistency.
(execute_one_pass): Likewise.
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi (revision 191852)
+++ doc/invoke.texi (working copy)
@@ -386,7 +386,7 @@ Objective-C and Objective-C++ Dialects}.
-fno-toplevel-reorder -fno-trapping-math -fno-zero-initialized-in-bss @gol
-fomit-frame-pointer -foptimize-register-move -foptimize-sibling-calls @gol
-fpartial-inlining -fpeel-loops -fpredictive-commoning @gol
--fprefetch-loop-arrays @gol
+-fprefetch-loop-arrays -fprofile-consistency-report @gol
-fprofile-correction -fprofile-dir=@var{path} -fprofile-generate @gol
-fprofile-generate=@var{path} @gol
-fprofile-use -fprofile-use=@var{path} -fprofile-values @gol
@@ -5149,6 +5149,11 @@ allocation for the WPA phase only.
Makes the compiler print some statistics about permanent memory
allocation before or after interprocedural optimization.
+@item -fprofile-consistency-report
+@opindex fprofile-consistency-report
+Makes the compiler print some statistics about consistency of the
+(estimated) profile.
+
@item -fstack-usage
@opindex fstack-usage
Makes the compiler output stack usage information for the program, on a
Index: common.opt
===================================================================
--- common.opt (revision 191852)
+++ common.opt (working copy)
@@ -1649,6 +1649,10 @@ fprofile-values
Common Report Var(flag_profile_values)
Insert code to profile values of expressions
+fprofile-consistency-report
+Common Report Var(profile_report)
+Report on consistency of profile
+
frandom-seed
Common Var(common_deferred_options) Defer
Index: toplev.c
===================================================================
--- toplev.c (revision 191852)
+++ toplev.c (working copy)
@@ -1815,6 +1815,9 @@ finalize (bool no_backend)
if (mem_report)
dump_memory_report (true);
+ if (profile_report)
+ dump_profile_consistency_report ();
+
/* Language-specific end of compilation actions. */
lang_hooks.finish ();
}
Index: passes.c
===================================================================
--- passes.c (revision 191852)
+++ passes.c (working copy)
@@ -1782,6 +1784,108 @@ execute_function_dump (void *data ATTRIB
}
}
+/* Hold statistic about profile consistency. */
+
+struct profile_record
+{
+ int num_mismatched_freq_in[2];
+ int num_mismatched_freq_out[2];
+ int num_mismatched_count_in[2];
+ int num_mismatched_count_out[2];
+ bool tested;
+};
+
+static struct profile_record *profile_record;
+
+/* Account profile inconsistencies for pass INDEX. If SUBPASS is non-zero, the
+ accounting happens after TODO. */
+
+static void
+check_profile_consistency (int index, int subpass)
+{
+ basic_block bb;
+ edge_iterator ei;
+ edge e;
+ int sum;
+ gcov_type lsum;
+
+ if (index == -1)
+ return;
+ if (!profile_record)
+ profile_record = XCNEWVEC (struct profile_record,
+ passes_by_id_size);
+ gcc_assert (index < passes_by_id_size && index >= 0);
+ gcc_assert (subpass < 2);
+ profile_record[index].tested = true;
+
+ FOR_ALL_BB (bb)
+ {
+ if (bb != EXIT_BLOCK_PTR_FOR_FUNCTION (cfun))
+ {
+ sum = 0;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ sum += e->probability;
+ if (EDGE_COUNT (bb->succs) && abs (sum - REG_BR_PROB_BASE) > 100)
+ profile_record[index].num_mismatched_freq_out[subpass]++;
+ lsum = 0;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ lsum += e->count;
+ if (EDGE_COUNT (bb->succs)
+ && (lsum - bb->count > 100 || lsum - bb->count < -100))
+ profile_record[index].num_mismatched_count_out[subpass]++;
+ }
+ if (bb != ENTRY_BLOCK_PTR_FOR_FUNCTION (cfun))
+ {
+ sum = 0;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ sum += EDGE_FREQUENCY (e);
+ if (abs (sum - bb->frequency) > 100
+ || (MAX (sum, bb->frequency) > 10
+ && abs ((sum - bb->frequency) * 100 / (MAX (sum,
bb->frequency) + 1)) > 10))
+ profile_record[index].num_mismatched_freq_in[subpass]++;
+ lsum = 0;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ lsum += e->count;
+ if (lsum - bb->count > 100 || lsum - bb->count < -100)
+ profile_record[index].num_mismatched_count_in[subpass]++;
+ }
+ }
+}
+
+/* Output profile consistency. */
+
+void
+dump_profile_consistency_report (void)
+{
+ int i, j;
+ int last_freq_in = 0, last_count_in = 0, last_freq_out = 0, last_count_out =
0;
+
+ if (!profile_record)
+ return;
+ fprintf (stderr, "\nProfile consistency report:\n");
+ for (i = 0; i < passes_by_id_size; i++)
+ for (j = 0 ; j < 2; j++)
+ if ((profile_record[i].num_mismatched_freq_in[j] != last_freq_in
+ || profile_record[i].num_mismatched_freq_out[j] != last_freq_out
+ || profile_record[i].num_mismatched_count_in[j] != last_count_in
+ || profile_record[i].num_mismatched_count_out[j] != last_count_out)
+ && profile_record[i].tested)
+ {
+ fprintf (stderr," Pass: %-20s %s mismatched in: %+4i (freqs) %+4i
(counts); "
+ "michmatched out: %+4i (freqs) %+4i (counts)\n",
+ passes_by_id [i]->name,
+ j ? "(after TODO)" : "(after pass)",
+ profile_record[i].num_mismatched_freq_in[j] - last_freq_in,
+ profile_record[i].num_mismatched_count_in[j] - last_count_in,
+ profile_record[i].num_mismatched_freq_out[j] - last_freq_out,
+ profile_record[i].num_mismatched_count_out[j] -
last_count_out);
+ last_freq_in = profile_record[i].num_mismatched_freq_in[j];
+ last_freq_out = profile_record[i].num_mismatched_freq_out[j];
+ last_count_in = profile_record[i].num_mismatched_count_in[j];
+ last_count_out = profile_record[i].num_mismatched_count_out[j];
+ }
+}
+
/* Perform all TODO actions that ought to be done on each function. */
static void
@@ -2050,9 +2150,16 @@ execute_one_ipa_transform_pass (struct c
if (pass->tv_id != TV_NONE)
timevar_pop (pass->tv_id);
+ if (profile_report && cfun && (cfun->curr_properties & PROP_cfg)
+ && profile_status != PROFILE_ABSENT)
+ check_profile_consistency (pass->static_pass_number, 0);
+
/* Run post-pass cleanup and verification. */
execute_todo (todo_after);
verify_interpass_invariants ();
+ if (profile_report && cfun && (cfun->curr_properties & PROP_cfg)
+ && profile_status != PROFILE_ABSENT)
+ check_profile_consistency (pass->static_pass_number, 1);
do_per_function (execute_function_dump, NULL);
pass_fini_dump_file (pass);
@@ -2218,8 +2325,16 @@ execute_one_pass (struct opt_pass *pass)
clean_graph_dump_file (dump_file_name);
}
+ if (profile_report && cfun && (cfun->curr_properties & PROP_cfg)
+ && profile_status != PROFILE_ABSENT)
+ check_profile_consistency (pass->static_pass_number, 0);
+
/* Run post-pass cleanup and verification. */
execute_todo (todo_after | pass->todo_flags_finish);
+ if (profile_report && cfun && (cfun->curr_properties & PROP_cfg)
+ && profile_status != PROFILE_ABSENT)
+ check_profile_consistency (pass->static_pass_number, 1);
+
verify_interpass_invariants ();
do_per_function (execute_function_dump, NULL);
if (pass->type == IPA_PASS)
Index: toplev.h
===================================================================
--- toplev.h (revision 191852)
+++ toplev.h (working copy)
@@ -49,6 +49,7 @@ extern void emit_debug_global_declaratio
extern void write_global_declarations (void);
extern void dump_memory_report (bool);
+extern void dump_profile_consistency_report (void);
extern void target_reinit (void);
