xref: /openbmc/qemu/contrib/plugins/howvec.c (revision 4921d0a7)
1 /*
2  * Copyright (C) 2019, Alex Bennée <alex.bennee@linaro.org>
3  *
4  * How vectorised is this code?
5  *
6  * Attempt to measure the amount of vectorisation that has been done
7  * on some code by counting classes of instruction.
8  *
9  * License: GNU GPL, version 2 or later.
10  *   See the COPYING file in the top-level directory.
11  */
12 #include <inttypes.h>
13 #include <assert.h>
14 #include <stdlib.h>
15 #include <inttypes.h>
16 #include <string.h>
17 #include <unistd.h>
18 #include <stdio.h>
19 #include <glib.h>
20 
21 #include <qemu-plugin.h>
22 
23 QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
24 
25 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
26 
27 typedef enum {
28     COUNT_CLASS,
29     COUNT_INDIVIDUAL,
30     COUNT_NONE
31 } CountType;
32 
33 static int limit = 50;
34 static bool do_inline;
35 static bool verbose;
36 
37 static GMutex lock;
38 static GHashTable *insns;
39 
40 typedef struct {
41     const char *class;
42     const char *opt;
43     uint32_t mask;
44     uint32_t pattern;
45     CountType what;
46     qemu_plugin_u64 count;
47 } InsnClassExecCount;
48 
49 typedef struct {
50     char *insn;
51     uint32_t opcode;
52     qemu_plugin_u64 count;
53     InsnClassExecCount *class;
54 } InsnExecCount;
55 
56 /*
57  * Matchers for classes of instructions, order is important.
58  *
59  * Your most precise match must be before looser matches. If no match
60  * is found in the table we can create an individual entry.
61  *
62  * 31..28 27..24 23..20 19..16 15..12 11..8 7..4 3..0
63  */
64 static InsnClassExecCount aarch64_insn_classes[] = {
65     /* "Reserved"" */
66     { "  UDEF",              "udef",   0xffff0000, 0x00000000, COUNT_NONE},
67     { "  SVE",               "sve",    0x1e000000, 0x04000000, COUNT_CLASS},
68     { "Reserved",            "res",    0x1e000000, 0x00000000, COUNT_CLASS},
69     /* Data Processing Immediate */
70     { "  PCrel addr",        "pcrel",  0x1f000000, 0x10000000, COUNT_CLASS},
71     { "  Add/Sub (imm,tags)", "asit",   0x1f800000, 0x11800000, COUNT_CLASS},
72     { "  Add/Sub (imm)",     "asi",    0x1f000000, 0x11000000, COUNT_CLASS},
73     { "  Logical (imm)",     "logi",   0x1f800000, 0x12000000, COUNT_CLASS},
74     { "  Move Wide (imm)",   "movwi",  0x1f800000, 0x12800000, COUNT_CLASS},
75     { "  Bitfield",          "bitf",   0x1f800000, 0x13000000, COUNT_CLASS},
76     { "  Extract",           "extr",   0x1f800000, 0x13800000, COUNT_CLASS},
77     { "Data Proc Imm",       "dpri",   0x1c000000, 0x10000000, COUNT_CLASS},
78     /* Branches */
79     { "  Cond Branch (imm)", "cndb",   0xfe000000, 0x54000000, COUNT_CLASS},
80     { "  Exception Gen",     "excp",   0xff000000, 0xd4000000, COUNT_CLASS},
81     { "    NOP",             "nop",    0xffffffff, 0xd503201f, COUNT_NONE},
82     { "  Hints",             "hint",   0xfffff000, 0xd5032000, COUNT_CLASS},
83     { "  Barriers",          "barr",   0xfffff000, 0xd5033000, COUNT_CLASS},
84     { "  PSTATE",            "psta",   0xfff8f000, 0xd5004000, COUNT_CLASS},
85     { "  System Insn",       "sins",   0xffd80000, 0xd5080000, COUNT_CLASS},
86     { "  System Reg",        "sreg",   0xffd00000, 0xd5100000, COUNT_CLASS},
87     { "  Branch (reg)",      "breg",   0xfe000000, 0xd6000000, COUNT_CLASS},
88     { "  Branch (imm)",      "bimm",   0x7c000000, 0x14000000, COUNT_CLASS},
89     { "  Cmp & Branch",      "cmpb",   0x7e000000, 0x34000000, COUNT_CLASS},
90     { "  Tst & Branch",      "tstb",   0x7e000000, 0x36000000, COUNT_CLASS},
91     { "Branches",            "branch", 0x1c000000, 0x14000000, COUNT_CLASS},
92     /* Loads and Stores */
93     { "  AdvSimd ldstmult",  "advlsm", 0xbfbf0000, 0x0c000000, COUNT_CLASS},
94     { "  AdvSimd ldstmult++", "advlsmp", 0xbfb00000, 0x0c800000, COUNT_CLASS},
95     { "  AdvSimd ldst",      "advlss", 0xbf9f0000, 0x0d000000, COUNT_CLASS},
96     { "  AdvSimd ldst++",    "advlssp", 0xbf800000, 0x0d800000, COUNT_CLASS},
97     { "  ldst excl",         "ldstx",  0x3f000000, 0x08000000, COUNT_CLASS},
98     { "    Prefetch",        "prfm",   0xff000000, 0xd8000000, COUNT_CLASS},
99     { "  Load Reg (lit)",    "ldlit",  0x1b000000, 0x18000000, COUNT_CLASS},
100     { "  ldst noalloc pair", "ldstnap", 0x3b800000, 0x28000000, COUNT_CLASS},
101     { "  ldst pair",         "ldstp",  0x38000000, 0x28000000, COUNT_CLASS},
102     { "  ldst reg",          "ldstr",  0x3b200000, 0x38000000, COUNT_CLASS},
103     { "  Atomic ldst",       "atomic", 0x3b200c00, 0x38200000, COUNT_CLASS},
104     { "  ldst reg (reg off)", "ldstro", 0x3b200b00, 0x38200800, COUNT_CLASS},
105     { "  ldst reg (pac)",    "ldstpa", 0x3b200200, 0x38200800, COUNT_CLASS},
106     { "  ldst reg (imm)",    "ldsti",  0x3b000000, 0x39000000, COUNT_CLASS},
107     { "Loads & Stores",      "ldst",   0x0a000000, 0x08000000, COUNT_CLASS},
108     /* Data Processing Register */
109     { "Data Proc Reg",       "dprr",   0x0e000000, 0x0a000000, COUNT_CLASS},
110     /* Scalar FP */
111     { "Scalar FP ",          "fpsimd", 0x0e000000, 0x0e000000, COUNT_CLASS},
112     /* Unclassified */
113     { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_CLASS},
114 };
115 
116 static InsnClassExecCount sparc32_insn_classes[] = {
117     { "Call",                "call",   0xc0000000, 0x40000000, COUNT_CLASS},
118     { "Branch ICond",        "bcc",    0xc1c00000, 0x00800000, COUNT_CLASS},
119     { "Branch Fcond",        "fbcc",   0xc1c00000, 0x01800000, COUNT_CLASS},
120     { "SetHi",               "sethi",  0xc1c00000, 0x01000000, COUNT_CLASS},
121     { "FPU ALU",             "fpu",    0xc1f00000, 0x81a00000, COUNT_CLASS},
122     { "ALU",                 "alu",    0xc0000000, 0x80000000, COUNT_CLASS},
123     { "Load/Store",          "ldst",   0xc0000000, 0xc0000000, COUNT_CLASS},
124     /* Unclassified */
125     { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_INDIVIDUAL},
126 };
127 
128 static InsnClassExecCount sparc64_insn_classes[] = {
129     { "SetHi & Branches",     "op0",   0xc0000000, 0x00000000, COUNT_CLASS},
130     { "Call",                 "op1",   0xc0000000, 0x40000000, COUNT_CLASS},
131     { "Arith/Logical/Move",   "op2",   0xc0000000, 0x80000000, COUNT_CLASS},
132     { "Arith/Logical/Move",   "op3",   0xc0000000, 0xc0000000, COUNT_CLASS},
133     /* Unclassified */
134     { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_INDIVIDUAL},
135 };
136 
137 /* Default matcher for currently unclassified architectures */
138 static InsnClassExecCount default_insn_classes[] = {
139     { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_INDIVIDUAL},
140 };
141 
142 typedef struct {
143     const char *qemu_target;
144     InsnClassExecCount *table;
145     int table_sz;
146 } ClassSelector;
147 
148 static ClassSelector class_tables[] = {
149     { "aarch64", aarch64_insn_classes, ARRAY_SIZE(aarch64_insn_classes) },
150     { "sparc",   sparc32_insn_classes, ARRAY_SIZE(sparc32_insn_classes) },
151     { "sparc64", sparc64_insn_classes, ARRAY_SIZE(sparc64_insn_classes) },
152     { NULL, default_insn_classes, ARRAY_SIZE(default_insn_classes) },
153 };
154 
155 static InsnClassExecCount *class_table;
156 static int class_table_sz;
157 
158 static gint cmp_exec_count(gconstpointer a, gconstpointer b)
159 {
160     InsnExecCount *ea = (InsnExecCount *) a;
161     InsnExecCount *eb = (InsnExecCount *) b;
162     uint64_t count_a = qemu_plugin_u64_sum(ea->count);
163     uint64_t count_b = qemu_plugin_u64_sum(eb->count);
164     return count_a > count_b ? -1 : 1;
165 }
166 
167 static void free_record(gpointer data)
168 {
169     InsnExecCount *rec = (InsnExecCount *) data;
170     qemu_plugin_scoreboard_free(rec->count.score);
171     g_free(rec->insn);
172     g_free(rec);
173 }
174 
175 static void plugin_exit(qemu_plugin_id_t id, void *p)
176 {
177     g_autoptr(GString) report = g_string_new("Instruction Classes:\n");
178     int i;
179     uint64_t total_count;
180     GList *counts;
181     InsnClassExecCount *class = NULL;
182 
183     for (i = 0; i < class_table_sz; i++) {
184         class = &class_table[i];
185         switch (class->what) {
186         case COUNT_CLASS:
187             total_count = qemu_plugin_u64_sum(class->count);
188             if (total_count || verbose) {
189                 g_string_append_printf(report,
190                                        "Class: %-24s\t(%" PRId64 " hits)\n",
191                                        class->class,
192                                        total_count);
193             }
194             break;
195         case COUNT_INDIVIDUAL:
196             g_string_append_printf(report, "Class: %-24s\tcounted individually\n",
197                                    class->class);
198             break;
199         case COUNT_NONE:
200             g_string_append_printf(report, "Class: %-24s\tnot counted\n",
201                                    class->class);
202             break;
203         default:
204             break;
205         }
206     }
207 
208     counts = g_hash_table_get_values(insns);
209     if (counts && g_list_next(counts)) {
210         g_string_append_printf(report, "Individual Instructions:\n");
211         counts = g_list_sort(counts, cmp_exec_count);
212 
213         for (i = 0; i < limit && g_list_next(counts);
214              i++, counts = g_list_next(counts)) {
215             InsnExecCount *rec = (InsnExecCount *) counts->data;
216             g_string_append_printf(report,
217                                    "Instr: %-24s\t(%" PRId64 " hits)"
218                                    "\t(op=0x%08x/%s)\n",
219                                    rec->insn,
220                                    qemu_plugin_u64_sum(rec->count),
221                                    rec->opcode,
222                                    rec->class ?
223                                    rec->class->class : "un-categorised");
224         }
225         g_list_free(counts);
226     }
227 
228     g_hash_table_destroy(insns);
229     for (i = 0; i < ARRAY_SIZE(class_tables); i++) {
230         for (int j = 0; j < class_tables[i].table_sz; ++j) {
231             qemu_plugin_scoreboard_free(class_tables[i].table[j].count.score);
232         }
233     }
234 
235 
236     qemu_plugin_outs(report->str);
237 }
238 
239 static void plugin_init(void)
240 {
241     insns = g_hash_table_new_full(NULL, g_direct_equal, NULL, &free_record);
242 }
243 
244 static void vcpu_insn_exec_before(unsigned int cpu_index, void *udata)
245 {
246     struct qemu_plugin_scoreboard *score = udata;
247     qemu_plugin_u64_add(qemu_plugin_scoreboard_u64(score), cpu_index, 1);
248 }
249 
250 static struct qemu_plugin_scoreboard *find_counter(
251     struct qemu_plugin_insn *insn)
252 {
253     int i;
254     uint64_t *cnt = NULL;
255     uint32_t opcode;
256     InsnClassExecCount *class = NULL;
257 
258     /*
259      * We only match the first 32 bits of the instruction which is
260      * fine for most RISCs but a bit limiting for CISC architectures.
261      * They would probably benefit from a more tailored plugin.
262      * However we can fall back to individual instruction counting.
263      */
264     opcode = *((uint32_t *)qemu_plugin_insn_data(insn));
265 
266     for (i = 0; !cnt && i < class_table_sz; i++) {
267         class = &class_table[i];
268         uint32_t masked_bits = opcode & class->mask;
269         if (masked_bits == class->pattern) {
270             break;
271         }
272     }
273 
274     g_assert(class);
275 
276     switch (class->what) {
277     case COUNT_NONE:
278         return NULL;
279     case COUNT_CLASS:
280         return class->count.score;
281     case COUNT_INDIVIDUAL:
282     {
283         InsnExecCount *icount;
284 
285         g_mutex_lock(&lock);
286         icount = (InsnExecCount *) g_hash_table_lookup(insns,
287                                                        GUINT_TO_POINTER(opcode));
288 
289         if (!icount) {
290             icount = g_new0(InsnExecCount, 1);
291             icount->opcode = opcode;
292             icount->insn = qemu_plugin_insn_disas(insn);
293             icount->class = class;
294             struct qemu_plugin_scoreboard *score =
295                 qemu_plugin_scoreboard_new(sizeof(uint64_t));
296             icount->count = qemu_plugin_scoreboard_u64(score);
297 
298             g_hash_table_insert(insns, GUINT_TO_POINTER(opcode),
299                                 (gpointer) icount);
300         }
301         g_mutex_unlock(&lock);
302 
303         return icount->count.score;
304     }
305     default:
306         g_assert_not_reached();
307     }
308 
309     return NULL;
310 }
311 
312 static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
313 {
314     size_t n = qemu_plugin_tb_n_insns(tb);
315     size_t i;
316 
317     for (i = 0; i < n; i++) {
318         struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
319         struct qemu_plugin_scoreboard *cnt = find_counter(insn);
320 
321         if (cnt) {
322             if (do_inline) {
323                 qemu_plugin_register_vcpu_insn_exec_inline_per_vcpu(
324                     insn, QEMU_PLUGIN_INLINE_ADD_U64,
325                     qemu_plugin_scoreboard_u64(cnt), 1);
326             } else {
327                 qemu_plugin_register_vcpu_insn_exec_cb(
328                     insn, vcpu_insn_exec_before, QEMU_PLUGIN_CB_NO_REGS, cnt);
329             }
330         }
331     }
332 }
333 
334 QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
335                                            const qemu_info_t *info,
336                                            int argc, char **argv)
337 {
338     int i;
339 
340     for (i = 0; i < ARRAY_SIZE(class_tables); i++) {
341         for (int j = 0; j < class_tables[i].table_sz; ++j) {
342             struct qemu_plugin_scoreboard *score =
343                 qemu_plugin_scoreboard_new(sizeof(uint64_t));
344             class_tables[i].table[j].count = qemu_plugin_scoreboard_u64(score);
345         }
346     }
347 
348     /* Select a class table appropriate to the guest architecture */
349     for (i = 0; i < ARRAY_SIZE(class_tables); i++) {
350         ClassSelector *entry = &class_tables[i];
351         if (!entry->qemu_target ||
352             strcmp(entry->qemu_target, info->target_name) == 0) {
353             class_table = entry->table;
354             class_table_sz = entry->table_sz;
355             break;
356         }
357     }
358 
359     for (i = 0; i < argc; i++) {
360         char *p = argv[i];
361         g_auto(GStrv) tokens = g_strsplit(p, "=", -1);
362         if (g_strcmp0(tokens[0], "inline") == 0) {
363             if (!qemu_plugin_bool_parse(tokens[0], tokens[1], &do_inline)) {
364                 fprintf(stderr, "boolean argument parsing failed: %s\n", p);
365                 return -1;
366             }
367         } else if (g_strcmp0(tokens[0], "verbose") == 0) {
368             if (!qemu_plugin_bool_parse(tokens[0], tokens[1], &verbose)) {
369                 fprintf(stderr, "boolean argument parsing failed: %s\n", p);
370                 return -1;
371             }
372         } else if (g_strcmp0(tokens[0], "count") == 0) {
373             char *value = tokens[1];
374             int j;
375             CountType type = COUNT_INDIVIDUAL;
376             if (*value == '!') {
377                 type = COUNT_NONE;
378                 value++;
379             }
380             for (j = 0; j < class_table_sz; j++) {
381                 if (strcmp(value, class_table[j].opt) == 0) {
382                     class_table[j].what = type;
383                     break;
384                 }
385             }
386         } else {
387             fprintf(stderr, "option parsing failed: %s\n", p);
388             return -1;
389         }
390     }
391 
392     plugin_init();
393 
394     qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
395     qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
396     return 0;
397 }
398