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      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 char	  diff__default_sort_order[] = "dso,symbol";
     22 static bool  force;
     23 static bool show_displacement;
     24 
     25 static int hists__add_entry(struct hists *self,
     26 			    struct addr_location *al, u64 period)
     27 {
     28 	if (__hists__add_entry(self, al, NULL, period) != NULL)
     29 		return 0;
     30 	return -ENOMEM;
     31 }
     32 
     33 static int diff__process_sample_event(union perf_event *event,
     34 				      struct perf_sample *sample,
     35 				      struct perf_evsel *evsel __used,
     36 				      struct perf_session *session)
     37 {
     38 	struct addr_location al;
     39 
     40 	if (perf_event__preprocess_sample(event, session, &al, sample, NULL) < 0) {
     41 		pr_warning("problem processing %d event, skipping it.\n",
     42 			   event->header.type);
     43 		return -1;
     44 	}
     45 
     46 	if (al.filtered || al.sym == NULL)
     47 		return 0;
     48 
     49 	if (hists__add_entry(&session->hists, &al, sample->period)) {
     50 		pr_warning("problem incrementing symbol period, skipping event\n");
     51 		return -1;
     52 	}
     53 
     54 	session->hists.stats.total_period += sample->period;
     55 	return 0;
     56 }
     57 
     58 static struct perf_event_ops event_ops = {
     59 	.sample	= diff__process_sample_event,
     60 	.mmap	= perf_event__process_mmap,
     61 	.comm	= perf_event__process_comm,
     62 	.exit	= perf_event__process_task,
     63 	.fork	= perf_event__process_task,
     64 	.lost	= perf_event__process_lost,
     65 	.ordered_samples = true,
     66 	.ordering_requires_timestamps = true,
     67 };
     68 
     69 static void perf_session__insert_hist_entry_by_name(struct rb_root *root,
     70 						    struct hist_entry *he)
     71 {
     72 	struct rb_node **p = &root->rb_node;
     73 	struct rb_node *parent = NULL;
     74 	struct hist_entry *iter;
     75 
     76 	while (*p != NULL) {
     77 		parent = *p;
     78 		iter = rb_entry(parent, struct hist_entry, rb_node);
     79 		if (hist_entry__cmp(he, iter) < 0)
     80 			p = &(*p)->rb_left;
     81 		else
     82 			p = &(*p)->rb_right;
     83 	}
     84 
     85 	rb_link_node(&he->rb_node, parent, p);
     86 	rb_insert_color(&he->rb_node, root);
     87 }
     88 
     89 static void hists__resort_entries(struct hists *self)
     90 {
     91 	unsigned long position = 1;
     92 	struct rb_root tmp = RB_ROOT;
     93 	struct rb_node *next = rb_first(&self->entries);
     94 
     95 	while (next != NULL) {
     96 		struct hist_entry *n = rb_entry(next, struct hist_entry, rb_node);
     97 
     98 		next = rb_next(&n->rb_node);
     99 		rb_erase(&n->rb_node, &self->entries);
    100 		n->position = position++;
    101 		perf_session__insert_hist_entry_by_name(&tmp, n);
    102 	}
    103 
    104 	self->entries = tmp;
    105 }
    106 
    107 static void hists__set_positions(struct hists *self)
    108 {
    109 	hists__output_resort(self);
    110 	hists__resort_entries(self);
    111 }
    112 
    113 static struct hist_entry *hists__find_entry(struct hists *self,
    114 					    struct hist_entry *he)
    115 {
    116 	struct rb_node *n = self->entries.rb_node;
    117 
    118 	while (n) {
    119 		struct hist_entry *iter = rb_entry(n, struct hist_entry, rb_node);
    120 		int64_t cmp = hist_entry__cmp(he, iter);
    121 
    122 		if (cmp < 0)
    123 			n = n->rb_left;
    124 		else if (cmp > 0)
    125 			n = n->rb_right;
    126 		else
    127 			return iter;
    128 	}
    129 
    130 	return NULL;
    131 }
    132 
    133 static void hists__match(struct hists *older, struct hists *newer)
    134 {
    135 	struct rb_node *nd;
    136 
    137 	for (nd = rb_first(&newer->entries); nd; nd = rb_next(nd)) {
    138 		struct hist_entry *pos = rb_entry(nd, struct hist_entry, rb_node);
    139 		pos->pair = hists__find_entry(older, pos);
    140 	}
    141 }
    142 
    143 static int __cmd_diff(void)
    144 {
    145 	int ret, i;
    146 	struct perf_session *session[2];
    147 
    148 	session[0] = perf_session__new(input_old, O_RDONLY, force, false, &event_ops);
    149 	session[1] = perf_session__new(input_new, O_RDONLY, force, false, &event_ops);
    150 	if (session[0] == NULL || session[1] == NULL)
    151 		return -ENOMEM;
    152 
    153 	for (i = 0; i < 2; ++i) {
    154 		ret = perf_session__process_events(session[i], &event_ops);
    155 		if (ret)
    156 			goto out_delete;
    157 	}
    158 
    159 	hists__output_resort(&session[1]->hists);
    160 	if (show_displacement)
    161 		hists__set_positions(&session[0]->hists);
    162 
    163 	hists__match(&session[0]->hists, &session[1]->hists);
    164 	hists__fprintf(&session[1]->hists, &session[0]->hists,
    165 		       show_displacement, stdout);
    166 out_delete:
    167 	for (i = 0; i < 2; ++i)
    168 		perf_session__delete(session[i]);
    169 	return ret;
    170 }
    171 
    172 static const char * const diff_usage[] = {
    173 	"perf diff [<options>] [old_file] [new_file]",
    174 	NULL,
    175 };
    176 
    177 static const struct option options[] = {
    178 	OPT_INCR('v', "verbose", &verbose,
    179 		    "be more verbose (show symbol address, etc)"),
    180 	OPT_BOOLEAN('M', "displacement", &show_displacement,
    181 		    "Show position displacement relative to baseline"),
    182 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
    183 		    "dump raw trace in ASCII"),
    184 	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
    185 	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
    186 		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
    187 	OPT_STRING('d', "dsos", &symbol_conf.dso_list_str, "dso[,dso...]",
    188 		   "only consider symbols in these dsos"),
    189 	OPT_STRING('C', "comms", &symbol_conf.comm_list_str, "comm[,comm...]",
    190 		   "only consider symbols in these comms"),
    191 	OPT_STRING('S', "symbols", &symbol_conf.sym_list_str, "symbol[,symbol...]",
    192 		   "only consider these symbols"),
    193 	OPT_STRING('s', "sort", &sort_order, "key[,key2...]",
    194 		   "sort by key(s): pid, comm, dso, symbol, parent"),
    195 	OPT_STRING('t', "field-separator", &symbol_conf.field_sep, "separator",
    196 		   "separator for columns, no spaces will be added between "
    197 		   "columns '.' is reserved."),
    198 	OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
    199 		    "Look for files with symbols relative to this directory"),
    200 	OPT_END()
    201 };
    202 
    203 int cmd_diff(int argc, const char **argv, const char *prefix __used)
    204 {
    205 	sort_order = diff__default_sort_order;
    206 	argc = parse_options(argc, argv, options, diff_usage, 0);
    207 	if (argc) {
    208 		if (argc > 2)
    209 			usage_with_options(diff_usage, options);
    210 		if (argc == 2) {
    211 			input_old = argv[0];
    212 			input_new = argv[1];
    213 		} else
    214 			input_new = argv[0];
    215 	} else if (symbol_conf.default_guest_vmlinux_name ||
    216 		   symbol_conf.default_guest_kallsyms) {
    217 		input_old = "perf.data.host";
    218 		input_new = "perf.data.guest";
    219 	}
    220 
    221 	symbol_conf.exclude_other = false;
    222 	if (symbol__init() < 0)
    223 		return -1;
    224 
    225 	setup_sorting(diff_usage, options);
    226 	setup_pager();
    227 
    228 	sort_entry__setup_elide(&sort_dso, symbol_conf.dso_list, "dso", NULL);
    229 	sort_entry__setup_elide(&sort_comm, symbol_conf.comm_list, "comm", NULL);
    230 	sort_entry__setup_elide(&sort_sym, symbol_conf.sym_list, "symbol", NULL);
    231 
    232 	return __cmd_diff();
    233 }
    234