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-rw-r--r--contrib/plugins/hotblocks.c145
1 files changed, 145 insertions, 0 deletions
diff --git a/contrib/plugins/hotblocks.c b/contrib/plugins/hotblocks.c
new file mode 100644
index 0000000000..3942a2ca54
--- /dev/null
+++ b/contrib/plugins/hotblocks.c
@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2019, Alex Bennée <alex.bennee@linaro.org>
+ *
+ * License: GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include <inttypes.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <glib.h>
+
+#include <qemu-plugin.h>
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
+
+static bool do_inline;
+
+/* Plugins need to take care of their own locking */
+static GMutex lock;
+static GHashTable *hotblocks;
+static guint64 limit = 20;
+
+/*
+ * Counting Structure
+ *
+ * The internals of the TCG are not exposed to plugins so we can only
+ * get the starting PC for each block. We cheat this slightly by
+ * xor'ing the number of instructions to the hash to help
+ * differentiate.
+ */
+typedef struct {
+ uint64_t start_addr;
+ uint64_t exec_count;
+ int trans_count;
+ unsigned long insns;
+} ExecCount;
+
+static gint cmp_exec_count(gconstpointer a, gconstpointer b)
+{
+ ExecCount *ea = (ExecCount *) a;
+ ExecCount *eb = (ExecCount *) b;
+ return ea->exec_count > eb->exec_count ? -1 : 1;
+}
+
+static void plugin_exit(qemu_plugin_id_t id, void *p)
+{
+ g_autoptr(GString) report = g_string_new("collected ");
+ GList *counts, *it;
+ int i;
+
+ g_mutex_lock(&lock);
+ g_string_append_printf(report, "%d entries in the hash table\n",
+ g_hash_table_size(hotblocks));
+ counts = g_hash_table_get_values(hotblocks);
+ it = g_list_sort(counts, cmp_exec_count);
+
+ if (it) {
+ g_string_append_printf(report, "pc, tcount, icount, ecount\n");
+
+ for (i = 0; i < limit && it->next; i++, it = it->next) {
+ ExecCount *rec = (ExecCount *) it->data;
+ g_string_append_printf(report, "%#016"PRIx64", %d, %ld, %"PRId64"\n",
+ rec->start_addr, rec->trans_count,
+ rec->insns, rec->exec_count);
+ }
+
+ g_list_free(it);
+ g_mutex_unlock(&lock);
+ }
+
+ qemu_plugin_outs(report->str);
+}
+
+static void plugin_init(void)
+{
+ hotblocks = g_hash_table_new(NULL, g_direct_equal);
+}
+
+static void vcpu_tb_exec(unsigned int cpu_index, void *udata)
+{
+ ExecCount *cnt;
+ uint64_t hash = (uint64_t) udata;
+
+ g_mutex_lock(&lock);
+ cnt = (ExecCount *) g_hash_table_lookup(hotblocks, (gconstpointer) hash);
+ /* should always succeed */
+ g_assert(cnt);
+ cnt->exec_count++;
+ g_mutex_unlock(&lock);
+}
+
+/*
+ * When do_inline we ask the plugin to increment the counter for us.
+ * Otherwise a helper is inserted which calls the vcpu_tb_exec
+ * callback.
+ */
+static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
+{
+ ExecCount *cnt;
+ uint64_t pc = qemu_plugin_tb_vaddr(tb);
+ unsigned long insns = qemu_plugin_tb_n_insns(tb);
+ uint64_t hash = pc ^ insns;
+
+ g_mutex_lock(&lock);
+ cnt = (ExecCount *) g_hash_table_lookup(hotblocks, (gconstpointer) hash);
+ if (cnt) {
+ cnt->trans_count++;
+ } else {
+ cnt = g_new0(ExecCount, 1);
+ cnt->start_addr = pc;
+ cnt->trans_count = 1;
+ cnt->insns = insns;
+ g_hash_table_insert(hotblocks, (gpointer) hash, (gpointer) cnt);
+ }
+
+ g_mutex_unlock(&lock);
+
+ if (do_inline) {
+ qemu_plugin_register_vcpu_tb_exec_inline(tb, QEMU_PLUGIN_INLINE_ADD_U64,
+ &cnt->exec_count, 1);
+ } else {
+ qemu_plugin_register_vcpu_tb_exec_cb(tb, vcpu_tb_exec,
+ QEMU_PLUGIN_CB_NO_REGS,
+ (void *)hash);
+ }
+}
+
+QEMU_PLUGIN_EXPORT
+int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
+ int argc, char **argv)
+{
+ if (argc && strcmp(argv[0], "inline") == 0) {
+ do_inline = true;
+ }
+
+ plugin_init();
+
+ qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
+ qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
+ return 0;
+}