On 6/19/19 10:56 AM, Martin Liška wrote:
> Thank you very much for the numbers. Today, I'm going to prepare the
> generalization of single-value counter to track N values.
Ok, here's a patch candidate that does tracking of most common N values. For
your test-case I can see:
pr69678.gcda: 01a90000: 18:COUNTERS indirect_call 9 counts
pr69678.gcda: 0: 350000000 1868707024 175000000 969338501
175000000 0 0 0
pr69678.gcda: 8: 0
So for now, you'll need to generalize get_most_common_single_value to return
N most common values.
Eventually we'll need to renamed the counter as it won't be tracking just a
single value
any longer. I can take care of it.
Can you please verify that the patch candidate works for you?
Thanks,
Martin
>From 93175b20aa794baf1795ff1ccb3ac0391c326ada Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Wed, 19 Jun 2019 14:15:14 +0200
Subject: [PATCH] Support N values in libgcov for single value counter type.
---
libgcc/libgcov-merge.c | 48 +++++++++++++++++++++------------------
libgcc/libgcov-profiler.c | 38 +++++++++++++++++++++++--------
2 files changed, 54 insertions(+), 32 deletions(-)
diff --git a/libgcc/libgcov-merge.c b/libgcc/libgcov-merge.c
index f778cc4b6b7..84367005663 100644
--- a/libgcc/libgcov-merge.c
+++ b/libgcc/libgcov-merge.c
@@ -89,49 +89,53 @@ __gcov_merge_time_profile (gcov_type *counters, unsigned n_counters)
static void
merge_single_value_set (gcov_type *counters)
{
- unsigned j;
- gcov_type value, counter;
-
/* First value is number of total executions of the profiler. */
gcov_type all = gcov_get_counter_ignore_scaling (-1);
counters[0] += all;
++counters;
+ /* Read all part values. */
+ gcov_type read_counters[2 * GCOV_DISK_SINGLE_VALUES];
+
for (unsigned i = 0; i < GCOV_DISK_SINGLE_VALUES; i++)
{
- value = gcov_get_counter_target ();
- counter = gcov_get_counter_ignore_scaling (-1);
+ read_counters[2 * i] = gcov_get_counter_target ();
+ read_counters[2 * i + 1] = gcov_get_counter_ignore_scaling (-1);
+ }
- if (counter == -1)
- {
- counters[1] = -1;
- /* We can't return as we need to read all counters. */
- continue;
- }
- else if (counter == 0 || counters[1] == -1)
- {
- /* We can't return as we need to read all counters. */
- continue;
- }
+ if (read_counters[1] == -1)
+ {
+ counters[1] = -1;
+ return;
+ }
+
+ for (unsigned i = 0; i < GCOV_DISK_SINGLE_VALUES; i++)
+ {
+ if (read_counters[2 * i + 1] == 0)
+ return;
+ unsigned j;
for (j = 0; j < GCOV_DISK_SINGLE_VALUES; j++)
{
- if (counters[2 * j] == value)
+ if (counters[2 * j] == read_counters[2 * i])
{
- counters[2 * j + 1] += counter;
+ counters[2 * j + 1] += read_counters[2 * i + 1];
break;
}
else if (counters[2 * j + 1] == 0)
{
- counters[2 * j] = value;
- counters[2 * j + 1] = counter;
+ counters[2 * j] += read_counters[2 * i];
+ counters[2 * j + 1] += read_counters[2 * i + 1];
break;
}
}
- /* We haven't found a free slot for the value, mark overflow. */
+ /* We haven't found a slot, bail out. */
if (j == GCOV_DISK_SINGLE_VALUES)
- counters[1] = -1;
+ {
+ counters[1] = -1;
+ return;
+ }
}
}
diff --git a/libgcc/libgcov-profiler.c b/libgcc/libgcov-profiler.c
index 9ba65b90df3..0ef400bdda7 100644
--- a/libgcc/libgcov-profiler.c
+++ b/libgcc/libgcov-profiler.c
@@ -118,20 +118,38 @@ static inline void
__gcov_one_value_profiler_body (gcov_type *counters, gcov_type value,
int use_atomic)
{
- if (value == counters[1])
- counters[2]++;
- else if (counters[2] == 0)
- {
- counters[2] = 1;
- counters[1] = value;
- }
- else
- counters[2]--;
-
if (use_atomic)
__atomic_fetch_add (&counters[0], 1, __ATOMIC_RELAXED);
else
counters[0]++;
+
+ ++counters;
+
+ /* We have GCOV_DISK_SINGLE_VALUES as we can keep multiple values
+ next to each other. */
+ unsigned sindex = 0;
+
+ for (unsigned i = 0; i < GCOV_DISK_SINGLE_VALUES; i++)
+ {
+ if (value == counters[2 * i])
+ {
+ counters[2 * i + 1]++;
+ return;
+ }
+ else if (counters[2 * i + 1] == 0)
+ {
+ /* We found an empty slot. */
+ counters[2 * i] = value;
+ counters[2 * i + 1] = 1;
+ return;
+ }
+
+ if (counters[2 * i + 1] < counters[2 * sindex + 1])
+ sindex = i;
+ }
+
+ /* We haven't found an empty slot, then decrement the smallest. */
+ counters[2 * sindex + 1]--;
}
#ifdef L_gcov_one_value_profiler_v2
--
2.21.0
