[PATCH] Indirect-call topn targets profiler (instrumentation)

Discussion:

Rong Xu

2014-10-06 16:50:10 UTC

Hi,

I ported the indirect-call topn target profile from google branch. It
implements the algorithm described in "Value profiling and
optimization" by Brad Calder and Peter Feller. This patch is about the
instrumentation. When --param=indir-call-topn-profile=1 is specified,
we will use indirection-call-topn profiler in this patch, instead of
indirect_call_profiler_v2.

Tested with gcc regression tests and the runtime patch (in a separated patch).

Thanks,

-Rong

Jan Hubicka

2014-10-06 18:22:40 UTC

Permalink

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.

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,
&current_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;

Xinliang David Li

2014-10-06 18:30:27 UTC

Permalink

Post by Jan Hubicka
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

Post by Jan Hubicka
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_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_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_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,
&current_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;
+ 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;
gcc_unreachable ();
}
@@ -432,9 +449,14 @@ stream_in_histogram_value (struct lto_input_block
break;
ncounters = 1;
break;
+
+ ncounters = (GCOV_ICALL_TOPN_VAL << 2) + 1;
+ break;
+
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,
+ stmt, callee));
return;
}
@@ -2011,9 +2037,9 @@ gimple_find_values_to_profile (histogram_values *v
hist->n_counters = 3;
break;
- hist->n_counters = 1;
- break;
+ hist->n_counters = 1;
+ break;
hist->n_counters = 2;
@@ -2023,6 +2049,10 @@ gimple_find_values_to_profile (histogram_values *v
hist->n_counters = 1;
break;
+ hist->n_counters = GCOV_ICALL_TOPN_NCOUNTS;
+ break;
+
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;
gimple_gen_ic_profiler (hist, t, 0);
break;

Jan Hubicka

2014-10-06 19:21:01 UTC

Permalink

Post by Xinliang David Li

Post by Jan Hubicka
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.

Well, for switch expansion one really wants a histogram of values across the switch
values for the decision tree balancing. But I guess this profiler does not fit
that very well.

Consider cases like

switch (a)
{
case 3:
case 5:
case 7:
prime();
case 2:
case 4:
case 6:
even();
default:
bogus ();
}

Arc profiling does tell you how often a is prime or even, but it does not help you
to balance the tree, because the value ranges are iinterlacing

Post by Xinliang David Li
David

Rong Xu

2014-10-06 20:11:57 UTC

Permalink

Post by Jan Hubicka

Post by Xinliang David Li

Post by Jan Hubicka
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.

Yes. That's doable. I'm just not sure if top 2 entries are enough. I
can see from your example that it will be useful for BBs having
multiple case stmt.

Post by Jan Hubicka

Post by Xinliang David Li
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.

Well, for switch expansion one really wants a histogram of values across the switch
values for the decision tree balancing. But I guess this profiler does not fit
that very well.
Consider cases like
switch (a)
{
prime();
even();
bogus ();
}
Arc profiling does tell you how often a is prime or even, but it does not help you
to balance the tree, because the value ranges are iinterlacing

Post by Xinliang David Li
David

Yes. I'm looking at this too. I actually ported the fdo-use part of
the patch and it passes spec2006. But it performs the transformation
using the old way (in gimple_ic_transform()) -- so I did not send out
that patch.
I'm trying to do this in the new way (in ipa-profile()). In any case,
that will be a separated patch.

Also, the switch expansion profile should be also a separated patch.

Is it ok to commit these two patches now?

Thanks,

-Rong

Post by Jan Hubicka

Post by Xinliang David Li

Post by Jan Hubicka
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_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_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_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,
&current_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;
+ 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;
gcc_unreachable ();
}
@@ -432,9 +449,14 @@ stream_in_histogram_value (struct lto_input_block
break;
ncounters = 1;
break;
+
+ ncounters = (GCOV_ICALL_TOPN_VAL << 2) + 1;
+ break;
+
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,
+ stmt, callee));
return;
}
@@ -2011,9 +2037,9 @@ gimple_find_values_to_profile (histogram_values *v
hist->n_counters = 3;
break;
- hist->n_counters = 1;
- break;
+ hist->n_counters = 1;
+ break;
hist->n_counters = 2;
@@ -2023,6 +2049,10 @@ gimple_find_values_to_profile (histogram_values *v
hist->n_counters = 1;
break;
+ hist->n_counters = GCOV_ICALL_TOPN_NCOUNTS;
+ break;
+
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;
gimple_gen_ic_profiler (hist, t, 0);
break;

Jan Hubicka

2014-10-06 20:31:18 UTC

Permalink

Post by Rong Xu
Yes. That's doable. I'm just not sure if top 2 entries are enough. I
can see from your example that it will be useful for BBs having
multiple case stmt.

I suppose we want real histogram profiler here. I.e. something that is given
value ranges and fill in the counts depending on value ranges.
Other case where your profiler may be useful is the division/modulo conversion.
For hashtables divisions/modules are often small sets of prime numbers.

Post by Rong Xu
Yes. I'm looking at this too. I actually ported the fdo-use part of
the patch and it passes spec2006. But it performs the transformation
using the old way (in gimple_ic_transform()) -- so I did not send out
that patch.
I'm trying to do this in the new way (in ipa-profile()). In any case,
that will be a separated patch.
Also, the switch expansion profile should be also a separated patch.
Is it ok to commit these two patches now?

Yes, it is OK, thanks!

Honza

Post by Rong Xu
Thanks,
-Rong

Post by Rong Xu
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_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_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_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,
&current_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;
+ 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;
gcc_unreachable ();
}
@@ -432,9 +449,14 @@ stream_in_histogram_value (struct lto_input_block
break;
ncounters = 1;
break;
+
+ ncounters = (GCOV_ICALL_TOPN_VAL << 2) + 1;
+ break;
+
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,
+ stmt, callee));
return;
}
@@ -2011,9 +2037,9 @@ gimple_find_values_to_profile (histogram_values *v
hist->n_counters = 3;
break;
- hist->n_counters = 1;
- break;
+ hist->n_counters = 1;
+ break;
hist->n_counters = 2;
@@ -2023,6 +2049,10 @@ gimple_find_values_to_profile (histogram_values *v
hist->n_counters = 1;
break;
+ hist->n_counters = GCOV_ICALL_TOPN_NCOUNTS;
+ break;
+
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;
gimple_gen_ic_profiler (hist, t, 0);
break;

Xinliang David Li

2014-10-06 20:35:53 UTC

Permalink

Post by Jan Hubicka

Post by Rong Xu
Yes. That's doable. I'm just not sure if top 2 entries are enough. I
can see from your example that it will be useful for BBs having
multiple case stmt.

yes, tracking value ranges sounds interesting. The topn is also
configurable to track more values, but it will become more expensive
to use.

David

Post by Jan Hubicka

Yes, it is OK, thanks!
Honza

Post by Rong Xu
Thanks,
-Rong