qemu

FORK: QEMU emulator
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hotblocks.c (4441B)

      1 /*
      2  * Copyright (C) 2019, Alex Bennée <alex.bennee@linaro.org>
      3  *
      4  * License: GNU GPL, version 2 or later.
      5  *   See the COPYING file in the top-level directory.
      6  */
      7 #include <inttypes.h>
      8 #include <assert.h>
      9 #include <stdlib.h>
     10 #include <inttypes.h>
     11 #include <string.h>
     12 #include <unistd.h>
     13 #include <stdio.h>
     14 #include <glib.h>
     15 
     16 #include <qemu-plugin.h>
     17 
     18 QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
     19 
     20 static bool do_inline;
     21 
     22 /* Plugins need to take care of their own locking */
     23 static GMutex lock;
     24 static GHashTable *hotblocks;
     25 static guint64 limit = 20;
     26 
     27 /*
     28  * Counting Structure
     29  *
     30  * The internals of the TCG are not exposed to plugins so we can only
     31  * get the starting PC for each block. We cheat this slightly by
     32  * xor'ing the number of instructions to the hash to help
     33  * differentiate.
     34  */
     35 typedef struct {
     36     uint64_t start_addr;
     37     uint64_t exec_count;
     38     int      trans_count;
     39     unsigned long insns;
     40 } ExecCount;
     41 
     42 static gint cmp_exec_count(gconstpointer a, gconstpointer b)
     43 {
     44     ExecCount *ea = (ExecCount *) a;
     45     ExecCount *eb = (ExecCount *) b;
     46     return ea->exec_count > eb->exec_count ? -1 : 1;
     47 }
     48 
     49 static void plugin_exit(qemu_plugin_id_t id, void *p)
     50 {
     51     g_autoptr(GString) report = g_string_new("collected ");
     52     GList *counts, *it;
     53     int i;
     54 
     55     g_mutex_lock(&lock);
     56     g_string_append_printf(report, "%d entries in the hash table\n",
     57                            g_hash_table_size(hotblocks));
     58     counts = g_hash_table_get_values(hotblocks);
     59     it = g_list_sort(counts, cmp_exec_count);
     60 
     61     if (it) {
     62         g_string_append_printf(report, "pc, tcount, icount, ecount\n");
     63 
     64         for (i = 0; i < limit && it->next; i++, it = it->next) {
     65             ExecCount *rec = (ExecCount *) it->data;
     66             g_string_append_printf(report, "0x%016"PRIx64", %d, %ld, %"PRId64"\n",
     67                                    rec->start_addr, rec->trans_count,
     68                                    rec->insns, rec->exec_count);
     69         }
     70 
     71         g_list_free(it);
     72         g_mutex_unlock(&lock);
     73     }
     74 
     75     qemu_plugin_outs(report->str);
     76 }
     77 
     78 static void plugin_init(void)
     79 {
     80     hotblocks = g_hash_table_new(NULL, g_direct_equal);
     81 }
     82 
     83 static void vcpu_tb_exec(unsigned int cpu_index, void *udata)
     84 {
     85     ExecCount *cnt;
     86     uint64_t hash = (uint64_t) udata;
     87 
     88     g_mutex_lock(&lock);
     89     cnt = (ExecCount *) g_hash_table_lookup(hotblocks, (gconstpointer) hash);
     90     /* should always succeed */
     91     g_assert(cnt);
     92     cnt->exec_count++;
     93     g_mutex_unlock(&lock);
     94 }
     95 
     96 /*
     97  * When do_inline we ask the plugin to increment the counter for us.
     98  * Otherwise a helper is inserted which calls the vcpu_tb_exec
     99  * callback.
    100  */
    101 static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
    102 {
    103     ExecCount *cnt;
    104     uint64_t pc = qemu_plugin_tb_vaddr(tb);
    105     size_t insns = qemu_plugin_tb_n_insns(tb);
    106     uint64_t hash = pc ^ insns;
    107 
    108     g_mutex_lock(&lock);
    109     cnt = (ExecCount *) g_hash_table_lookup(hotblocks, (gconstpointer) hash);
    110     if (cnt) {
    111         cnt->trans_count++;
    112     } else {
    113         cnt = g_new0(ExecCount, 1);
    114         cnt->start_addr = pc;
    115         cnt->trans_count = 1;
    116         cnt->insns = insns;
    117         g_hash_table_insert(hotblocks, (gpointer) hash, (gpointer) cnt);
    118     }
    119 
    120     g_mutex_unlock(&lock);
    121 
    122     if (do_inline) {
    123         qemu_plugin_register_vcpu_tb_exec_inline(tb, QEMU_PLUGIN_INLINE_ADD_U64,
    124                                                  &cnt->exec_count, 1);
    125     } else {
    126         qemu_plugin_register_vcpu_tb_exec_cb(tb, vcpu_tb_exec,
    127                                              QEMU_PLUGIN_CB_NO_REGS,
    128                                              (void *)hash);
    129     }
    130 }
    131 
    132 QEMU_PLUGIN_EXPORT
    133 int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
    134                         int argc, char **argv)
    135 {
    136     for (int i = 0; i < argc; i++) {
    137         char *opt = argv[i];
    138         g_autofree char **tokens = g_strsplit(opt, "=", 2);
    139         if (g_strcmp0(tokens[0], "inline") == 0) {
    140             if (!qemu_plugin_bool_parse(tokens[0], tokens[1], &do_inline)) {
    141                 fprintf(stderr, "boolean argument parsing failed: %s\n", opt);
    142                 return -1;
    143             }
    144         } else {
    145             fprintf(stderr, "option parsing failed: %s\n", opt);
    146             return -1;
    147         }
    148     }
    149 
    150     plugin_init();
    151 
    152     qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
    153     qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
    154     return 0;
    155 }