xref: /openbmc/qemu/contrib/plugins/howvec.c (revision 53c7c924)
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     uint64_t count;
47 } InsnClassExecCount;
48 
49 typedef struct {
50     char *insn;
51     uint32_t opcode;
52     uint64_t 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     return ea->count > eb->count ? -1 : 1;
163 }
164 
165 static void free_record(gpointer data)
166 {
167     InsnExecCount *rec = (InsnExecCount *) data;
168     g_free(rec->insn);
169     g_free(rec);
170 }
171 
172 static void plugin_exit(qemu_plugin_id_t id, void *p)
173 {
174     g_autoptr(GString) report = g_string_new("Instruction Classes:\n");
175     int i;
176     GList *counts;
177     InsnClassExecCount *class = NULL;
178 
179     for (i = 0; i < class_table_sz; i++) {
180         class = &class_table[i];
181         switch (class->what) {
182         case COUNT_CLASS:
183             if (class->count || verbose) {
184                 g_string_append_printf(report, "Class: %-24s\t(%ld hits)\n",
185                                        class->class,
186                                        class->count);
187             }
188             break;
189         case COUNT_INDIVIDUAL:
190             g_string_append_printf(report, "Class: %-24s\tcounted individually\n",
191                                    class->class);
192             break;
193         case COUNT_NONE:
194             g_string_append_printf(report, "Class: %-24s\tnot counted\n",
195                                    class->class);
196             break;
197         default:
198             break;
199         }
200     }
201 
202     counts = g_hash_table_get_values(insns);
203     if (counts && g_list_next(counts)) {
204         g_string_append_printf(report, "Individual Instructions:\n");
205         counts = g_list_sort(counts, cmp_exec_count);
206 
207         for (i = 0; i < limit && g_list_next(counts);
208              i++, counts = g_list_next(counts)) {
209             InsnExecCount *rec = (InsnExecCount *) counts->data;
210             g_string_append_printf(report,
211                                    "Instr: %-24s\t(%ld hits)\t(op=0x%08x/%s)\n",
212                                    rec->insn,
213                                    rec->count,
214                                    rec->opcode,
215                                    rec->class ?
216                                    rec->class->class : "un-categorised");
217         }
218         g_list_free(counts);
219     }
220 
221     g_hash_table_destroy(insns);
222 
223     qemu_plugin_outs(report->str);
224 }
225 
226 static void plugin_init(void)
227 {
228     insns = g_hash_table_new_full(NULL, g_direct_equal, NULL, &free_record);
229 }
230 
231 static void vcpu_insn_exec_before(unsigned int cpu_index, void *udata)
232 {
233     uint64_t *count = (uint64_t *) udata;
234     (*count)++;
235 }
236 
237 static uint64_t *find_counter(struct qemu_plugin_insn *insn)
238 {
239     int i;
240     uint64_t *cnt = NULL;
241     uint32_t opcode;
242     InsnClassExecCount *class = NULL;
243 
244     /*
245      * We only match the first 32 bits of the instruction which is
246      * fine for most RISCs but a bit limiting for CISC architectures.
247      * They would probably benefit from a more tailored plugin.
248      * However we can fall back to individual instruction counting.
249      */
250     opcode = *((uint32_t *)qemu_plugin_insn_data(insn));
251 
252     for (i = 0; !cnt && i < class_table_sz; i++) {
253         class = &class_table[i];
254         uint32_t masked_bits = opcode & class->mask;
255         if (masked_bits == class->pattern) {
256             break;
257         }
258     }
259 
260     g_assert(class);
261 
262     switch (class->what) {
263     case COUNT_NONE:
264         return NULL;
265     case COUNT_CLASS:
266         return &class->count;
267     case COUNT_INDIVIDUAL:
268     {
269         InsnExecCount *icount;
270 
271         g_mutex_lock(&lock);
272         icount = (InsnExecCount *) g_hash_table_lookup(insns,
273                                                        GUINT_TO_POINTER(opcode));
274 
275         if (!icount) {
276             icount = g_new0(InsnExecCount, 1);
277             icount->opcode = opcode;
278             icount->insn = qemu_plugin_insn_disas(insn);
279             icount->class = class;
280 
281             g_hash_table_insert(insns, GUINT_TO_POINTER(opcode),
282                                 (gpointer) icount);
283         }
284         g_mutex_unlock(&lock);
285 
286         return &icount->count;
287     }
288     default:
289         g_assert_not_reached();
290     }
291 
292     return NULL;
293 }
294 
295 static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
296 {
297     size_t n = qemu_plugin_tb_n_insns(tb);
298     size_t i;
299 
300     for (i = 0; i < n; i++) {
301         uint64_t *cnt;
302         struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
303         cnt = find_counter(insn);
304 
305         if (cnt) {
306             if (do_inline) {
307                 qemu_plugin_register_vcpu_insn_exec_inline(
308                     insn, QEMU_PLUGIN_INLINE_ADD_U64, cnt, 1);
309             } else {
310                 qemu_plugin_register_vcpu_insn_exec_cb(
311                     insn, vcpu_insn_exec_before, QEMU_PLUGIN_CB_NO_REGS, cnt);
312             }
313         }
314     }
315 }
316 
317 QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
318                                            const qemu_info_t *info,
319                                            int argc, char **argv)
320 {
321     int i;
322 
323     /* Select a class table appropriate to the guest architecture */
324     for (i = 0; i < ARRAY_SIZE(class_tables); i++) {
325         ClassSelector *entry = &class_tables[i];
326         if (!entry->qemu_target ||
327             strcmp(entry->qemu_target, info->target_name) == 0) {
328             class_table = entry->table;
329             class_table_sz = entry->table_sz;
330             break;
331         }
332     }
333 
334     for (i = 0; i < argc; i++) {
335         char *p = argv[i];
336         g_auto(GStrv) tokens = g_strsplit(p, "=", -1);
337         if (g_strcmp0(tokens[0], "inline") == 0) {
338             if (!qemu_plugin_bool_parse(tokens[0], tokens[1], &do_inline)) {
339                 fprintf(stderr, "boolean argument parsing failed: %s\n", p);
340                 return -1;
341             }
342         } else if (g_strcmp0(tokens[0], "verbose") == 0) {
343             if (!qemu_plugin_bool_parse(tokens[0], tokens[1], &verbose)) {
344                 fprintf(stderr, "boolean argument parsing failed: %s\n", p);
345                 return -1;
346             }
347         } else if (g_strcmp0(tokens[0], "count") == 0) {
348             char *value = tokens[1];
349             int j;
350             CountType type = COUNT_INDIVIDUAL;
351             if (*value == '!') {
352                 type = COUNT_NONE;
353                 value++;
354             }
355             for (j = 0; j < class_table_sz; j++) {
356                 if (strcmp(value, class_table[j].opt) == 0) {
357                     class_table[j].what = type;
358                     break;
359                 }
360             }
361         } else {
362             fprintf(stderr, "option parsing failed: %s\n", p);
363             return -1;
364         }
365     }
366 
367     plugin_init();
368 
369     qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
370     qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
371     return 0;
372 }
373