+2020-02-18 Martin Liska <mliska@suse.cz>
+
+ PR ipa/92924
+ * common.opt: Add -fprofile-reproducibility.
+ * doc/invoke.texi: Document it.
+ * value-prof.c (dump_histogram_value):
+ Document and support behavior for counters[0]
+ being a negative value.
+ (get_nth_most_common_value): Handle negative
+ counters[0] in respect to flag_profile_reproducible.
+
2020-02-18 Jakub Jelinek <jakub@redhat.com>
PR ipa/93797
Common Joined RejectNegative Var(flag_profile_exclude_files)
Instrument only functions from files where names do not match all the regular expressions (separated by a semi-colon).
+Enum
+Name(profile_reproducibility) Type(enum profile_reproducibility) UnknownError(unknown profile reproducibility method %qs)
+
+EnumValue
+Enum(profile_reproducibility) String(serial) Value(PROFILE_REPRODUCIBILITY_SERIAL)
+
+EnumValue
+Enum(profile_reproducibility) String(parallel-runs) Value(PROFILE_REPRODUCIBILITY_PARALLEL_RUNS)
+
+EnumValue
+Enum(profile_reproducibility) String(multithreaded) Value(PROFILE_REPRODUCIBILITY_MULTITHREADED)
+
+fprofile-reproducible
+Common Joined RejectNegative Var(flag_profile_reproducible) Enum(profile_reproducibility) Init(PROFILE_REPRODUCIBILITY_SERIAL)
+-fprofile-reproducible=[serial|parallel-runs|multithreaded] Control level of reproducibility of profile gathered by -fprofile-generate.
+
Enum
Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
PROFILE_UPDATE_PREFER_ATOMIC
};
+/* Type of profile reproducibility methods. */
+enum profile_reproducibility {
+ PROFILE_REPRODUCIBILITY_SERIAL,
+ PROFILE_REPRODUCIBILITY_PARALLEL_RUNS,
+ PROFILE_REPRODUCIBILITY_MULTITHREADED
+};
+
/* Types of unwind/exception handling info that can be generated. */
enum unwind_info_type
-fprofile-abs-path @gol
-fprofile-dir=@var{path} -fprofile-generate -fprofile-generate=@var{path} @gol
-fprofile-note=@var{path} -fprofile-update=@var{method} @gol
--fprofile-filter-files=@var{regex} -fprofile-exclude-files=@var{regex} @gol
+-fprofile-filter-files=@var{regex} -fprofile-exclude-files=@var{regex} -fprofile-reproducibility @gol
-fsanitize=@var{style} -fsanitize-recover -fsanitize-recover=@var{style} @gol
-fasan-shadow-offset=@var{number} -fsanitize-sections=@var{s1},@var{s2},... @gol
-fsanitize-undefined-trap-on-error -fbounds-check @gol
For example, @option{-fprofile-exclude-files=/usr/*} will prevent instrumentation
of all files that are located in @file{/usr/} folder.
+@item -fprofile-reproducible
+@opindex fprofile-reproducible
+Control level of reproducibility of profile gathered by
+@code{-fprofile-generate}. This makes it possible to rebuild program
+with same outcome which is useful, for example, for distribution
+packages.
+
+With @option{-fprofile-reproducibility=serial} the profile gathered by
+@option{-fprofile-generate} is reproducible provided the trained program
+behaves the same at each invocation of the train run, it is not
+multi-threaded and profile data streaming is always done in the same
+order. Note that profile streaming happens at the end of program run but
+also before @code{fork} function is invoked.
+
+Note that it is quite common that execution counts of some part of
+programs depends, for example, on length of temporary file names or
+memory space randomization (that may affect hash-table collision rate).
+Such non-reproducible part of programs may be annotated by
+@code{no_instrument_function} function attribute. @code{gcov-dump} with
+@option{-l} can be used to dump gathered data and verify that they are
+indeed reproducible.
+
+With @option{-fprofile-reproducibility=parallel-runs} collected profile
+stays reproducible regardless the order of streaming of the data into
+gcda files. This setting makes it possible to run multiple instances of
+instrumented program in parallel (such as with @code{make -j}). This
+reduces quality of gathered data, in particular of indirect call
+profiling.
+
@item -fsanitize=address
@opindex fsanitize=address
Enable AddressSanitizer, a fast memory error detector.
? "Top N value counter" : "Indirect call counter"));
if (hist->hvalue.counters)
{
- fprintf (dump_file, " all: %" PRId64 ", values: ",
- (int64_t) hist->hvalue.counters[0]);
+ fprintf (dump_file, " all: %" PRId64 "%s, values: ",
+ abs ((int64_t) hist->hvalue.counters[0]),
+ hist->hvalue.counters[0] < 0
+ ? " (values missing)": "");
for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
{
fprintf (dump_file, "[%" PRId64 ":%" PRId64 "]",
/* Return the n-th value count of TOPN_VALUE histogram. If
there's a value, return true and set VALUE and COUNT
- arguments. */
+ arguments.
+
+ Counters have the following meaning.
+
+ abs (counters[0]) is the number of executions
+ for i in 0 ... TOPN-1
+ counters[2 * i + 1] is target
+ abs (counters[2 * i + 2]) is corresponding hitrate counter.
+
+ Value of counters[0] negative when counter became
+ full during merging and some values are lost. */
bool
get_nth_most_common_value (gimple *stmt, const char *counter_type,
histogram_value hist, gcov_type *value,
gcov_type *count, gcov_type *all, unsigned n)
{
- if (hist->hvalue.counters[2] == -1)
- return false;
-
gcc_assert (n < GCOV_TOPN_VALUES);
*count = 0;
*value = 0;
- gcov_type read_all = hist->hvalue.counters[0];
+ gcov_type read_all = abs (hist->hvalue.counters[0]);
gcov_type v = hist->hvalue.counters[2 * n + 1];
gcov_type c = hist->hvalue.counters[2 * n + 2];
+ if (hist->hvalue.counters[0] < 0
+ && (flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS
+ || (flag_profile_reproducible
+ == PROFILE_REPRODUCIBILITY_MULTITHREADED)))
+ return false;
+
/* Indirect calls can't be verified. */
if (stmt
&& check_counter (stmt, counter_type, &c, &read_all,
+2020-02-18 Martin Liska <mliska@suse.cz>
+
+ PR ipa/92924
+ * libgcov-merge.c (merge_topn_values_set): Record
+ when a TOP N counter becomes invalid. When merging
+ remove a smallest value if the space is needed.
+
2020-02-12 Sandra Loosemore <sandra@codesourcery.com>
PR libstdc++/79193
#ifdef L_gcov_merge_topn
+/* To merging of TOPN profiles.
+ counters[0] is the number of executions
+ for i in 0 ... TOPN-1
+ counters[2 * i + 1] is target
+ counters[2 * i + 2] is corresponding hitrate counter.
+
+ Because we prune counters only those with probability >= 1/TOPN are
+ present now.
+
+ We use sign of counters[0] to track whether the number of different
+ targets exceeds TOPN. */
+
static void
merge_topn_values_set (gcov_type *counters)
{
/* First value is number of total executions of the profiler. */
- gcov_type all = gcov_get_counter_ignore_scaling (-1);
- counters[0] += all;
+ gcov_type all = gcov_get_counter ();
+ gcov_type *total = &counters[0];
++counters;
+ /* Negative value means that counter is missing some of values. */
+ if (all < 0)
+ *total = -(*total);
+
+ *total += all;
+
/* Read all part values. */
gcov_type read_counters[2 * GCOV_TOPN_VALUES];
-
for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
{
read_counters[2 * i] = gcov_get_counter_target ();
read_counters[2 * i + 1] = gcov_get_counter_ignore_scaling (-1);
}
- if (read_counters[1] == -1)
- {
- counters[1] = -1;
- return;
- }
-
for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
{
if (read_counters[2 * i + 1] == 0)
continue;
unsigned j;
- int slot = -1;
+ int slot = 0;
for (j = 0; j < GCOV_TOPN_VALUES; j++)
{
counters[2 * j + 1] += read_counters[2 * i + 1];
break;
}
- else if (counters[2 * j + 1] == 0)
+ else if (counters[2 * j + 1] < counters[2 * slot + 1])
slot = j;
}
if (j == GCOV_TOPN_VALUES)
{
- if (slot > 0)
+ gcov_type slot_count = counters[2 * slot + 1];
+ /* We found an empty slot. */
+ if (slot_count == 0)
{
/* If we found empty slot, add the value. */
counters[2 * slot] = read_counters[2 * i];
}
else
{
- /* We haven't found a slot, bail out. */
- counters[1] = -1;
- return;
+ /* Here we are loosing some values. */
+ if (*total >= 0)
+ *total = -(*total);
+ if (read_counters[2 * i + 1] > slot_count)
+ {
+ counters[2 * slot] = read_counters[2 * i];
+ counters[2 * slot + 1] = read_counters[2 * i + 1];
+ }
+ else
+ counters[2 * slot + 1] -= read_counters[2 * i + 1];
}
}
}
projects / gcc.git / commitdiff