builtin-diff.c

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/*
 * builtin-diff.c
 *
 * Builtin diff command: Analyze two perf.data input files, look up and read
 * DSOs and symbol information, sort them and produce a diff.
 */
#include "builtin.h"

#include "util/debug.h"
#include "util/event.h"
#include "util/hist.h"
#include "util/evsel.h"
#include "util/evlist.h"
#include "util/session.h"
#include "util/tool.h"
#include "util/sort.h"
#include "util/symbol.h"
#include "util/util.h"

#include <stdlib.h>

static char const *input_old = "perf.data.old",
          *input_new = "perf.data";
static char   diff__default_sort_order[] = "dso,symbol";
static bool  force;
static bool show_displacement;

static int hists__add_entry(struct hists *self,
                struct addr_location *al, u64 period)
{
    if (__hists__add_entry(self, al, NULL, period) != NULL)
        return 0;
    return -ENOMEM;
}

static int diff__process_sample_event(struct perf_tool *tool __maybe_unused,
                      union perf_event *event,
                      struct perf_sample *sample,
                      struct perf_evsel *evsel,
                      struct machine *machine)
{
    struct addr_location al;

    if (perf_event__preprocess_sample(event, machine, &al, sample, NULL) < 0) {
        pr_warning("problem processing %d event, skipping it.\n",
               event->header.type);
        return -1;
    }

    if (al.filtered || al.sym == NULL)
        return 0;

    if (hists__add_entry(&evsel->hists, &al, sample->period)) {
        pr_warning("problem incrementing symbol period, skipping event\n");
        return -1;
    }

    evsel->hists.stats.total_period += sample->period;
    return 0;
}

static struct perf_tool tool = {
    .sample = diff__process_sample_event,
    .mmap   = perf_event__process_mmap,
    .comm   = perf_event__process_comm,
    .exit   = perf_event__process_task,
    .fork   = perf_event__process_task,
    .lost   = perf_event__process_lost,
    .ordered_samples = true,
    .ordering_requires_timestamps = true,
};

static void insert_hist_entry_by_name(struct rb_root *root,
                      struct hist_entry *he)
{
    struct rb_node **p = &root->rb_node;
    struct rb_node *parent = NULL;
    struct hist_entry *iter;

    while (*p != NULL) {
        parent = *p;
        iter = rb_entry(parent, struct hist_entry, rb_node);
        if (hist_entry__cmp(he, iter) < 0)
            p = &(*p)->rb_left;
        else
            p = &(*p)->rb_right;
    }

    rb_link_node(&he->rb_node, parent, p);
    rb_insert_color(&he->rb_node, root);
}

static void hists__name_resort(struct hists *self, bool sort)
{
    unsigned long position = 1;
    struct rb_root tmp = RB_ROOT;
    struct rb_node *next = rb_first(&self->entries);

    while (next != NULL) {
        struct hist_entry *n = rb_entry(next, struct hist_entry, rb_node);

        next = rb_next(&n->rb_node);
        n->position = position++;

        if (sort) {
            rb_erase(&n->rb_node, &self->entries);
            insert_hist_entry_by_name(&tmp, n);
        }
    }

    if (sort)
        self->entries = tmp;
}

static struct hist_entry *hists__find_entry(struct hists *self,
                        struct hist_entry *he)
{
    struct rb_node *n = self->entries.rb_node;

    while (n) {
        struct hist_entry *iter = rb_entry(n, struct hist_entry, rb_node);
        int64_t cmp = hist_entry__cmp(he, iter);

        if (cmp < 0)
            n = n->rb_left;
        else if (cmp > 0)
            n = n->rb_right;
        else
            return iter;
    }

    return NULL;
}

static void hists__match(struct hists *older, struct hists *newer)
{
    struct rb_node *nd;

    for (nd = rb_first(&newer->entries); nd; nd = rb_next(nd)) {
        struct hist_entry *pos = rb_entry(nd, struct hist_entry, rb_node);
        pos->pair = hists__find_entry(older, pos);
    }
}

static struct perf_evsel *evsel_match(struct perf_evsel *evsel,
                      struct perf_evlist *evlist)
{
    struct perf_evsel *e;

    list_for_each_entry(e, &evlist->entries, node)
        if (perf_evsel__match2(evsel, e))
            return e;

    return NULL;
}

static void perf_evlist__resort_hists(struct perf_evlist *evlist, bool name)
{
    struct perf_evsel *evsel;

    list_for_each_entry(evsel, &evlist->entries, node) {
        struct hists *hists = &evsel->hists;

        hists__output_resort(hists);

        /*
         * The hists__name_resort only sets possition
         * if name is false.
         */
        if (name || ((!name) && show_displacement))
            hists__name_resort(hists, name);
    }
}

static int __cmd_diff(void)
{
    int ret, i;
#define older (session[0])
#define newer (session[1])
    struct perf_session *session[2];
    struct perf_evlist *evlist_new, *evlist_old;
    struct perf_evsel *evsel;
    bool first = true;

    older = perf_session__new(input_old, O_RDONLY, force, false,
                  &tool);
    newer = perf_session__new(input_new, O_RDONLY, force, false,
                  &tool);
    if (session[0] == NULL || session[1] == NULL)
        return -ENOMEM;

    for (i = 0; i < 2; ++i) {
        ret = perf_session__process_events(session[i], &tool);
        if (ret)
            goto out_delete;
    }

    evlist_old = older->evlist;
    evlist_new = newer->evlist;

    perf_evlist__resort_hists(evlist_old, true);
    perf_evlist__resort_hists(evlist_new, false);

    list_for_each_entry(evsel, &evlist_new->entries, node) {
        struct perf_evsel *evsel_old;

        evsel_old = evsel_match(evsel, evlist_old);
        if (!evsel_old)
            continue;

        fprintf(stdout, "%s# Event '%s'\n#\n", first ? "" : "\n",
            perf_evsel__name(evsel));

        first = false;

        hists__match(&evsel_old->hists, &evsel->hists);
        hists__fprintf(&evsel->hists, true, 0, 0, stdout);
    }

out_delete:
    for (i = 0; i < 2; ++i)
        perf_session__delete(session[i]);
    return ret;
#undef older
#undef newer
}

static const char * const diff_usage[] = {
    "perf diff [<options>] [old_file] [new_file]",
    NULL,
};

static const struct option options[] = {
    OPT_INCR('v', "verbose", &verbose,
            "be more verbose (show symbol address, etc)"),
    OPT_BOOLEAN('M', "displacement", &show_displacement,
            "Show position displacement relative to baseline"),
    OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
            "dump raw trace in ASCII"),
    OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
    OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
            "load module symbols - WARNING: use only with -k and LIVE kernel"),
    OPT_STRING('d', "dsos", &symbol_conf.dso_list_str, "dso[,dso...]",
           "only consider symbols in these dsos"),
    OPT_STRING('C', "comms", &symbol_conf.comm_list_str, "comm[,comm...]",
           "only consider symbols in these comms"),
    OPT_STRING('S', "symbols", &symbol_conf.sym_list_str, "symbol[,symbol...]",
           "only consider these symbols"),
    OPT_STRING('s', "sort", &sort_order, "key[,key2...]",
           "sort by key(s): pid, comm, dso, symbol, parent"),
    OPT_STRING('t', "field-separator", &symbol_conf.field_sep, "separator",
           "separator for columns, no spaces will be added between "
           "columns '.' is reserved."),
    OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
            "Look for files with symbols relative to this directory"),
    OPT_END()
};

static void ui_init(void)
{
    perf_hpp__init();

    /* No overhead column. */
    perf_hpp__column_enable(PERF_HPP__OVERHEAD, false);

    /* Display baseline/delta/displacement columns. */
    perf_hpp__column_enable(PERF_HPP__BASELINE, true);
    perf_hpp__column_enable(PERF_HPP__DELTA, true);

    if (show_displacement)
        perf_hpp__column_enable(PERF_HPP__DISPL, true);
}

int cmd_diff(int argc, const char **argv, const char *prefix __maybe_unused)
{
    sort_order = diff__default_sort_order;
    argc = parse_options(argc, argv, options, diff_usage, 0);
    if (argc) {
        if (argc > 2)
            usage_with_options(diff_usage, options);
        if (argc == 2) {
            input_old = argv[0];
            input_new = argv[1];
        } else
            input_new = argv[0];
    } else if (symbol_conf.default_guest_vmlinux_name ||
           symbol_conf.default_guest_kallsyms) {
        input_old = "perf.data.host";
        input_new = "perf.data.guest";
    }

    symbol_conf.exclude_other = false;
    if (symbol__init() < 0)
        return -1;

    ui_init();

    setup_sorting(diff_usage, options);
    setup_pager();

    sort_entry__setup_elide(&sort_dso, symbol_conf.dso_list, "dso", NULL);
    sort_entry__setup_elide(&sort_comm, symbol_conf.comm_list, "comm", NULL);
    sort_entry__setup_elide(&sort_sym, symbol_conf.sym_list, "symbol", NULL);

    return __cmd_diff();
}