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authorTavian Barnes <tavianator@tavianator.com>2014-08-19 17:10:03 -0400
committerTavian Barnes <tavianator@tavianator.com>2015-10-25 11:03:56 -0400
commit7b09710392d35fb55b52031d447a542d99fc6b4b (patch)
tree270eb927ee8c52ceeb99926ebf4843704775a610 /libdimension/base/profile.c
parent200c86b91ea7063d35be3bffc11c5da53c054653 (diff)
downloaddimension-7b09710392d35fb55b52031d447a542d99fc6b4b.tar.xz
Modularize the libdimension codebase.
Diffstat (limited to 'libdimension/base/profile.c')
-rw-r--r--libdimension/base/profile.c168
1 files changed, 168 insertions, 0 deletions
diff --git a/libdimension/base/profile.c b/libdimension/base/profile.c
new file mode 100644
index 0000000..87f27c1
--- /dev/null
+++ b/libdimension/base/profile.c
@@ -0,0 +1,168 @@
+/*************************************************************************
+ * Copyright (C) 2010-2011 Tavian Barnes <tavianator@tavianator.com> *
+ * *
+ * This file is part of The Dimension Library. *
+ * *
+ * The Dimension Library is free software; you can redistribute it and/ *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version. *
+ * *
+ * The Dimension Library is distributed in the hope that it will be *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
+ * Lesser General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU Lesser General Public *
+ * License along with this program. If not, see *
+ * <http://www.gnu.org/licenses/>. *
+ *************************************************************************/
+
+/**
+ * @file
+ * Branch profile accounting.
+ */
+
+#include "internal.h"
+#include "internal/concurrency.h"
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdio.h>
+
+/// Information on one predicted branch.
+typedef struct {
+ char *location;
+ uint64_t predicted, branches;
+} dmnsn_branch;
+
+/// Count of mispredicted branches.
+static dmnsn_dictionary *dmnsn_profile = NULL;
+/// Mutex which protects \c dmnsn_profile.
+static pthread_mutex_t dmnsn_profile_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+/// Thread-local count of mispredicted branches.
+static pthread_key_t dmnsn_thread_profile;
+/// Initialize the thread-specific pointer exactly once.
+static pthread_once_t dmnsn_thread_profile_once = PTHREAD_ONCE_INIT;
+
+/// Add thread-specific profile data to the global counts.
+static void
+dmnsn_profile_globalize(void *ptr)
+{
+ dmnsn_branch *branch = ptr;
+ dmnsn_branch *global = dmnsn_dictionary_at(dmnsn_profile, branch->location);
+ if (global) {
+ global->predicted += branch->predicted;
+ global->branches += branch->branches;
+ dmnsn_free(branch->location);
+ } else {
+ dmnsn_dictionary_insert(dmnsn_profile, branch->location, branch);
+ }
+}
+
+/// Destructor function for thread-specific profile data.
+static void
+dmnsn_delete_thread_profile(void *ptr)
+{
+ dmnsn_dictionary *thread_profile = ptr;
+
+ dmnsn_lock_mutex(&dmnsn_profile_mutex);
+ dmnsn_dictionary_apply(thread_profile, dmnsn_profile_globalize);
+ dmnsn_unlock_mutex(&dmnsn_profile_mutex);
+
+ dmnsn_delete_dictionary(thread_profile);
+}
+
+/// Initialize the thread-specific pointer.
+static void
+dmnsn_initialize_thread_profile(void)
+{
+ dmnsn_key_create(&dmnsn_thread_profile, dmnsn_delete_thread_profile);
+
+ dmnsn_lock_mutex(&dmnsn_profile_mutex);
+ dmnsn_profile = dmnsn_new_dictionary(sizeof(dmnsn_branch));
+ dmnsn_unlock_mutex(&dmnsn_profile_mutex);
+}
+
+/// Get the thread-specific profile data.
+static dmnsn_dictionary *
+dmnsn_get_thread_profile(void)
+{
+ dmnsn_once(&dmnsn_thread_profile_once, dmnsn_initialize_thread_profile);
+ return pthread_getspecific(dmnsn_thread_profile);
+}
+
+/// Set the thread-specific profile data.
+static void
+dmnsn_set_thread_profile(dmnsn_dictionary *thread_profile)
+{
+ dmnsn_setspecific(dmnsn_thread_profile, thread_profile);
+}
+
+bool
+dmnsn_expect(bool result, bool expected, const char *func, const char *file,
+ unsigned int line)
+{
+ int size = snprintf(NULL, 0, "%s:%s:%u", file, func, line) + 1;
+ if (size < 1) {
+ dmnsn_error("sprintf() failed.");
+ }
+
+ char key[size];
+ if (snprintf(key, size, "%s:%s:%u", file, func, line) < 0) {
+ dmnsn_error("sprintf() failed.");
+ }
+
+ dmnsn_dictionary *thread_profile = dmnsn_get_thread_profile();
+ if (!thread_profile) {
+ thread_profile = dmnsn_new_dictionary(sizeof(dmnsn_branch));
+ dmnsn_set_thread_profile(thread_profile);
+ }
+
+ dmnsn_branch *branch = dmnsn_dictionary_at(thread_profile, key);
+ if (branch) {
+ ++branch->branches;
+ if (result == expected) {
+ ++branch->predicted;
+ }
+ } else {
+ dmnsn_branch new_branch = {
+ .location = dmnsn_strdup(key),
+ .predicted = (result == expected) ? 1 : 0,
+ .branches = 1
+ };
+ dmnsn_dictionary_insert(thread_profile, key, &new_branch);
+ }
+
+ return result;
+}
+
+static void
+dmnsn_print_bad_prediction(void *ptr)
+{
+ dmnsn_branch *branch = ptr;
+ double rate = ((double)branch->predicted)/branch->branches;
+ if (rate < 0.75 || branch->branches < 100000) {
+ fprintf(stderr,
+ "Bad branch prediction: %s: %" PRIu64 "/%" PRIu64 " (%g%%)\n",
+ branch->location, branch->predicted, branch->branches, 100.0*rate);
+ }
+
+ dmnsn_free(branch->location);
+}
+
+DMNSN_DESTRUCTOR static void
+dmnsn_print_bad_predictions(void)
+{
+ dmnsn_dictionary *thread_profile = dmnsn_get_thread_profile();
+ if (thread_profile) {
+ dmnsn_delete_thread_profile(thread_profile);
+ dmnsn_set_thread_profile(NULL);
+ }
+
+ dmnsn_lock_mutex(&dmnsn_profile_mutex);
+ dmnsn_dictionary_apply(dmnsn_profile, dmnsn_print_bad_prediction);
+ dmnsn_delete_dictionary(dmnsn_profile);
+ dmnsn_profile = NULL;
+ dmnsn_unlock_mutex(&dmnsn_profile_mutex);
+}