On Mon, Oct 6, 2014 at 11:22 AM, Jan Hubicka <hubi...@ucw.cz> wrote:
> Rong,
> Would be possible to use topn profiler to get resonale histograms for switch
> expansion, too? In that case it may make sense to have value version of it
> as well.
The underlying topn_profiler can be used the same way as the current
one_value profiler for different scenarios. However, I wonder if it is
useful for switch value profiling -- the arc profiling can do the
same.
David
>
> Otherwise the patch seems OK. I would implement it myself by introducing
> separate
> variables holding the topn profiler declaration, but can not think of
> downsides of
> doing it your way.
>
> The topn profiler should be better on determining the dominating target, so
> perhaps
> you could look into hooking it into ipa-profile.c. Extending speculative
> edges for
> multiple targets ought to be also quite easy - we need to update
> speculative_call_info
> to collect edges annotated to a given call stmt into a vector instead of
> taking the
> two references it does now.
>
> It would be also very nice to update it to handle case where all the edges
> are direct
> so we can use it tospeculatively inlinine functions that can be interposed at
> runtime.
>
> Thanks,
> Honza
>
> Index: gcc/tree-profile.c
> ===================================================================
> --- gcc/tree-profile.c (revision 215886)
> +++ gcc/tree-profile.c (working copy)
> @@ -56,6 +56,7 @@ along with GCC; see the file COPYING3. If not see
> #include "target.h"
> #include "tree-cfgcleanup.h"
> #include "tree-nested.h"
> +#include "params.h"
>
> static GTY(()) tree gcov_type_node;
> static GTY(()) tree tree_interval_profiler_fn;
> @@ -101,7 +102,10 @@ init_ic_make_global_vars (void)
> {
> ic_void_ptr_var
> = build_decl (UNKNOWN_LOCATION, VAR_DECL,
> - get_identifier ("__gcov_indirect_call_callee"),
> + get_identifier (
> + (PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) ?
> + "__gcov_indirect_call_topn_callee" :
> + "__gcov_indirect_call_callee")),
> ptr_void);
> TREE_PUBLIC (ic_void_ptr_var) = 1;
> DECL_EXTERNAL (ic_void_ptr_var) = 1;
> @@ -131,7 +135,10 @@ init_ic_make_global_vars (void)
> {
> ic_gcov_type_ptr_var
> = build_decl (UNKNOWN_LOCATION, VAR_DECL,
> - get_identifier ("__gcov_indirect_call_counters"),
> + get_identifier (
> + (PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) ?
> + "__gcov_indirect_call_topn_counters" :
> + "__gcov_indirect_call_counters")),
> gcov_type_ptr);
> TREE_PUBLIC (ic_gcov_type_ptr_var) = 1;
> DECL_EXTERNAL (ic_gcov_type_ptr_var) = 1;
> @@ -226,8 +233,10 @@ gimple_init_edge_profiler (void)
> ptr_void,
> NULL_TREE);
> tree_indirect_call_profiler_fn
> - = build_fn_decl ("__gcov_indirect_call_profiler_v2",
> - ic_profiler_fn_type);
> + = build_fn_decl ( (PARAM_VALUE
> (PARAM_INDIR_CALL_TOPN_PROFILE) ?
> + "__gcov_indirect_call_topn_profiler":
> + "__gcov_indirect_call_profiler_v2"),
> + ic_profiler_fn_type);
> }
> TREE_NOTHROW (tree_indirect_call_profiler_fn) = 1;
> DECL_ATTRIBUTES (tree_indirect_call_profiler_fn)
> @@ -398,6 +407,12 @@ gimple_gen_ic_profiler (histogram_value value, uns
> gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
> tree ref_ptr = tree_coverage_counter_addr (tag, base);
>
> + if ( (PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) &&
> + tag == GCOV_COUNTER_V_INDIR) ||
> + (!PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) &&
> + tag == GCOV_COUNTER_ICALL_TOPNV))
> + return;
> +
> ref_ptr = force_gimple_operand_gsi (&gsi, ref_ptr,
> true, NULL_TREE, true, GSI_SAME_STMT);
>
> @@ -442,8 +457,7 @@ gimple_gen_ic_func_profiler (void)
> stmt1: __gcov_indirect_call_profiler_v2 (profile_id,
> ¤t_function_decl)
> */
> - gsi =
> - gsi_after_labels (split_edge
> (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))));
> + gsi = gsi_after_labels (split_edge (single_succ_edge
> (ENTRY_BLOCK_PTR_FOR_FN (cfun))));
>
> cur_func = force_gimple_operand_gsi (&gsi,
> build_addr (current_function_decl,
> Index: gcc/value-prof.c
> ===================================================================
> --- gcc/value-prof.c (revision 215886)
> +++ gcc/value-prof.c (working copy)
> @@ -60,6 +60,7 @@ along with GCC; see the file COPYING3. If not see
> #include "builtins.h"
> #include "tree-nested.h"
> #include "hash-set.h"
> +#include "params.h"
>
> /* In this file value profile based optimizations are placed. Currently the
> following optimizations are implemented (for more detailed descriptions
> @@ -359,6 +360,22 @@ dump_histogram_value (FILE *dump_file, histogram_v
> }
> fprintf (dump_file, ".\n");
> break;
> + case HIST_TYPE_INDIR_CALL_TOPN:
> + fprintf (dump_file, "Indirect call topn ");
> + if (hist->hvalue.counters)
> + {
> + int i;
> +
> + fprintf (dump_file, "accu:%"PRId64, hist->hvalue.counters[0]);
> + for (i = 1; i < (GCOV_ICALL_TOPN_VAL << 2); i += 2)
> + {
> + fprintf (dump_file, " target:%"PRId64 " value:%"PRId64,
> + (int64_t) hist->hvalue.counters[i],
> + (int64_t) hist->hvalue.counters[i+1]);
> + }
> + }
> + fprintf (dump_file, ".\n");
> + break;
> case HIST_TYPE_MAX:
> gcc_unreachable ();
> }
> @@ -432,9 +449,14 @@ stream_in_histogram_value (struct lto_input_block
> break;
>
> case HIST_TYPE_IOR:
> - case HIST_TYPE_TIME_PROFILE:
> + case HIST_TYPE_TIME_PROFILE:
> ncounters = 1;
> break;
> +
> + case HIST_TYPE_INDIR_CALL_TOPN:
> + ncounters = (GCOV_ICALL_TOPN_VAL << 2) + 1;
> + break;
> +
> case HIST_TYPE_MAX:
> gcc_unreachable ();
> }
> @@ -1920,8 +1942,12 @@ gimple_indirect_call_to_profile (gimple stmt, hist
>
> values->reserve (3);
>
> - values->quick_push (gimple_alloc_histogram_value (cfun,
> HIST_TYPE_INDIR_CALL,
> - stmt, callee));
> + values->quick_push (gimple_alloc_histogram_value (
> + cfun,
> + PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) ?
> + HIST_TYPE_INDIR_CALL_TOPN :
> + HIST_TYPE_INDIR_CALL,
> + stmt, callee));
>
> return;
> }
> @@ -2011,9 +2037,9 @@ gimple_find_values_to_profile (histogram_values *v
> hist->n_counters = 3;
> break;
>
> - case HIST_TYPE_TIME_PROFILE:
> - hist->n_counters = 1;
> - break;
> + case HIST_TYPE_TIME_PROFILE:
> + hist->n_counters = 1;
> + break;
>
> case HIST_TYPE_AVERAGE:
> hist->n_counters = 2;
> @@ -2023,6 +2049,10 @@ gimple_find_values_to_profile (histogram_values *v
> hist->n_counters = 1;
> break;
>
> + case HIST_TYPE_INDIR_CALL_TOPN:
> + hist->n_counters = GCOV_ICALL_TOPN_NCOUNTS;
> + break;
> +
> default:
> gcc_unreachable ();
> }
> Index: gcc/value-prof.h
> ===================================================================
> --- gcc/value-prof.h (revision 215886)
> +++ gcc/value-prof.h (working copy)
> @@ -35,6 +35,8 @@ enum hist_type
> HIST_TYPE_AVERAGE, /* Compute average value (sum of all values). */
> HIST_TYPE_IOR, /* Used to compute expected alignment. */
> HIST_TYPE_TIME_PROFILE, /* Used for time profile */
> + HIST_TYPE_INDIR_CALL_TOPN, /* Tries to identify the top N most frequently
> + called functions in indirect call. */
> HIST_TYPE_MAX
> };
>
> Index: gcc/profile.c
> ===================================================================
> --- gcc/profile.c (revision 215886)
> +++ gcc/profile.c (working copy)
> @@ -183,6 +183,7 @@ instrument_values (histogram_values values)
> break;
>
> case HIST_TYPE_INDIR_CALL:
> + case HIST_TYPE_INDIR_CALL_TOPN:
> gimple_gen_ic_profiler (hist, t, 0);
> break;
>
