xref: /linux-6.15/tools/perf/builtin-diff.c (revision 586bc5cc)
1 /*
2  * builtin-diff.c
3  *
4  * Builtin diff command: Analyze two perf.data input files, look up and read
5  * DSOs and symbol information, sort them and produce a diff.
6  */
7 #include "builtin.h"
8 
9 #include "util/debug.h"
10 #include "util/event.h"
11 #include "util/hist.h"
12 #include "util/session.h"
13 #include "util/sort.h"
14 #include "util/symbol.h"
15 #include "util/util.h"
16 
17 #include <stdlib.h>
18 
19 static char	   const *input_old = "perf.data.old",
20 			 *input_new = "perf.data";
21 static int	   force;
22 static bool 	   show_percent;
23 
24 struct symbol_conf symbol_conf;
25 
26 static int perf_session__add_hist_entry(struct perf_session *self,
27 					struct addr_location *al, u64 count)
28 {
29 	bool hit;
30 	struct hist_entry *he = __perf_session__add_hist_entry(self, al, NULL,
31 							       count, &hit);
32 	if (he == NULL)
33 		return -ENOMEM;
34 
35 	if (hit)
36 		he->count += count;
37 
38 	return 0;
39 }
40 
41 static int diff__process_sample_event(event_t *event, struct perf_session *session)
42 {
43 	struct addr_location al;
44 	struct sample_data data = { .period = 1, };
45 
46 	dump_printf("(IP, %d): %d: %p\n", event->header.misc,
47 		    event->ip.pid, (void *)(long)event->ip.ip);
48 
49 	if (event__preprocess_sample(event, session, &al, NULL) < 0) {
50 		pr_warning("problem processing %d event, skipping it.\n",
51 			   event->header.type);
52 		return -1;
53 	}
54 
55 	event__parse_sample(event, session->sample_type, &data);
56 
57 	if (al.sym && perf_session__add_hist_entry(session, &al, data.period)) {
58 		pr_warning("problem incrementing symbol count, skipping event\n");
59 		return -1;
60 	}
61 
62 	session->events_stats.total += data.period;
63 	return 0;
64 }
65 
66 static struct perf_event_ops event_ops = {
67 	.process_sample_event = diff__process_sample_event,
68 	.process_mmap_event   = event__process_mmap,
69 	.process_comm_event   = event__process_comm,
70 	.process_exit_event   = event__process_task,
71 	.process_fork_event   = event__process_task,
72 	.process_lost_event   = event__process_lost,
73 };
74 
75 static void perf_session__insert_hist_entry_by_name(struct rb_root *root,
76 						    struct hist_entry *he)
77 {
78 	struct rb_node **p = &root->rb_node;
79 	struct rb_node *parent = NULL;
80 	struct hist_entry *iter;
81 
82 	while (*p != NULL) {
83 		int cmp;
84 		parent = *p;
85 		iter = rb_entry(parent, struct hist_entry, rb_node);
86 
87 		cmp = strcmp(he->map->dso->name, iter->map->dso->name);
88 		if (cmp > 0)
89 			p = &(*p)->rb_left;
90 		else if (cmp < 0)
91 			p = &(*p)->rb_right;
92 		else {
93 			cmp = strcmp(he->sym->name, iter->sym->name);
94 			if (cmp > 0)
95 				p = &(*p)->rb_left;
96 			else
97 				p = &(*p)->rb_right;
98 		}
99 	}
100 
101 	rb_link_node(&he->rb_node, parent, p);
102 	rb_insert_color(&he->rb_node, root);
103 }
104 
105 static void perf_session__resort_by_name(struct perf_session *self)
106 {
107 	unsigned long position = 1;
108 	struct rb_root tmp = RB_ROOT;
109 	struct rb_node *next = rb_first(&self->hists);
110 
111 	while (next != NULL) {
112 		struct hist_entry *n = rb_entry(next, struct hist_entry, rb_node);
113 
114 		next = rb_next(&n->rb_node);
115 		rb_erase(&n->rb_node, &self->hists);
116 		n->position = position++;
117 		perf_session__insert_hist_entry_by_name(&tmp, n);
118 	}
119 
120 	self->hists = tmp;
121 }
122 
123 static struct hist_entry *
124 perf_session__find_hist_entry_by_name(struct perf_session *self,
125 				      struct hist_entry *he)
126 {
127 	struct rb_node *n = self->hists.rb_node;
128 
129 	while (n) {
130 		struct hist_entry *iter = rb_entry(n, struct hist_entry, rb_node);
131 		int cmp = strcmp(he->map->dso->name, iter->map->dso->name);
132 
133 		if (cmp > 0)
134 			n = n->rb_left;
135 		else if (cmp < 0)
136 			n = n->rb_right;
137 		else {
138 			cmp = strcmp(he->sym->name, iter->sym->name);
139 			if (cmp > 0)
140 				n = n->rb_left;
141 			else if (cmp < 0)
142 				n = n->rb_right;
143 			else
144 				return iter;
145 		}
146 	}
147 
148 	return NULL;
149 }
150 
151 static void perf_session__match_hists(struct perf_session *old_session,
152 				      struct perf_session *new_session)
153 {
154 	struct rb_node *nd;
155 
156 	perf_session__resort_by_name(old_session);
157 
158 	for (nd = rb_first(&new_session->hists); nd; nd = rb_next(nd)) {
159 		struct hist_entry *pos = rb_entry(nd, struct hist_entry, rb_node);
160 		pos->pair = perf_session__find_hist_entry_by_name(old_session, pos);
161 	}
162 }
163 
164 static size_t hist_entry__fprintf_matched(struct hist_entry *self,
165 					  unsigned long pos,
166 					  struct perf_session *session,
167 					  struct perf_session *pair_session,
168 					  FILE *fp)
169 {
170 	u64 old_count = 0;
171 	char displacement[16];
172 	size_t printed;
173 
174 	if (self->pair != NULL) {
175 		long pdiff = (long)self->pair->position - (long)pos;
176 		old_count = self->pair->count;
177 		if (pdiff == 0)
178 			goto blank;
179 		snprintf(displacement, sizeof(displacement), "%+4ld", pdiff);
180 	} else {
181 blank:		memset(displacement, ' ', sizeof(displacement));
182 	}
183 
184 	printed = fprintf(fp, "%4lu %5.5s ", pos, displacement);
185 
186 	if (show_percent) {
187 		double old_percent = (old_count * 100) / pair_session->events_stats.total,
188 		       new_percent = (self->count * 100) / session->events_stats.total;
189 		double diff = old_percent - new_percent;
190 
191 		if (verbose)
192 			printed += fprintf(fp, " %3.2f%% %3.2f%%", old_percent, new_percent);
193 
194 		if ((u64)diff != 0)
195 			printed += fprintf(fp, " %+4.2F%%", diff);
196 		else
197 			printed += fprintf(fp, "       ");
198 	} else {
199 		if (verbose)
200 			printed += fprintf(fp, " %9Lu %9Lu", old_count, self->count);
201 		printed += fprintf(fp, " %+9Ld", (s64)self->count - (s64)old_count);
202 	}
203 
204 	return printed + fprintf(fp, " %25.25s   %s\n",
205 				 self->map->dso->name, self->sym->name);
206 }
207 
208 static size_t perf_session__fprintf_matched_hists(struct perf_session *self,
209 						  struct perf_session *pair,
210 						  FILE *fp)
211 {
212 	struct rb_node *nd;
213 	size_t printed = 0;
214 	unsigned long pos = 1;
215 
216 	for (nd = rb_first(&self->hists); nd; nd = rb_next(nd)) {
217 		struct hist_entry *he = rb_entry(nd, struct hist_entry, rb_node);
218 		printed += hist_entry__fprintf_matched(he, pos++, self, pair, fp);
219 	}
220 
221 	return printed;
222 }
223 
224 static int __cmd_diff(void)
225 {
226 	int ret, i;
227 	struct perf_session *session[2];
228 
229 	session[0] = perf_session__new(input_old, O_RDONLY, force, &symbol_conf);
230 	session[1] = perf_session__new(input_new, O_RDONLY, force, &symbol_conf);
231 	if (session[0] == NULL || session[1] == NULL)
232 		return -ENOMEM;
233 
234 	for (i = 0; i < 2; ++i) {
235 		ret = perf_session__process_events(session[i], &event_ops);
236 		if (ret)
237 			goto out_delete;
238 		perf_session__output_resort(session[i], session[i]->events_stats.total);
239 	}
240 
241 	perf_session__match_hists(session[0], session[1]);
242 	perf_session__fprintf_matched_hists(session[1], session[0], stdout);
243 out_delete:
244 	for (i = 0; i < 2; ++i)
245 		perf_session__delete(session[i]);
246 	return ret;
247 }
248 
249 static const char *const diff_usage[] = {
250 	"perf diff [<options>] [old_file] [new_file]",
251 };
252 
253 static const struct option options[] = {
254 	OPT_BOOLEAN('v', "verbose", &verbose,
255 		    "be more verbose (show symbol address, etc)"),
256 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
257 		    "dump raw trace in ASCII"),
258 	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
259 	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
260 		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
261 	OPT_BOOLEAN('p', "percentages", &show_percent,
262 		    "Don't shorten the pathnames taking into account the cwd"),
263 	OPT_BOOLEAN('P', "full-paths", &event_ops.full_paths,
264 		    "Don't shorten the pathnames taking into account the cwd"),
265 	OPT_END()
266 };
267 
268 int cmd_diff(int argc, const char **argv, const char *prefix __used)
269 {
270 	if (symbol__init(&symbol_conf) < 0)
271 		return -1;
272 
273 	setup_sorting(diff_usage, options);
274 
275 	argc = parse_options(argc, argv, options, diff_usage, 0);
276 	if (argc) {
277 		if (argc > 2)
278 			usage_with_options(diff_usage, options);
279 		if (argc == 2) {
280 			input_old = argv[0];
281 			input_new = argv[1];
282 		} else
283 			input_new = argv[0];
284 	}
285 
286 	setup_pager();
287 	return __cmd_diff();
288 }
289