builtin-diff.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * 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 "util/data.h"
#include "util/config.h"

#include <errno.h>
#include <inttypes.h>
#include <stdlib.h>
#include <math.h>

/* Diff command specific HPP columns. */
enum {
    PERF_HPP_DIFF__BASELINE,
    PERF_HPP_DIFF__PERIOD,
    PERF_HPP_DIFF__PERIOD_BASELINE,
    PERF_HPP_DIFF__DELTA,
    PERF_HPP_DIFF__RATIO,
    PERF_HPP_DIFF__WEIGHTED_DIFF,
    PERF_HPP_DIFF__FORMULA,
    PERF_HPP_DIFF__DELTA_ABS,

    PERF_HPP_DIFF__MAX_INDEX
};

struct diff_hpp_fmt {
    struct perf_hpp_fmt  fmt;
    int          idx;
    char            *header;
    int          header_width;
};

struct data__file {
    struct perf_session *session;
    struct perf_data     data;
    int          idx;
    struct hists        *hists;
    struct diff_hpp_fmt  fmt[PERF_HPP_DIFF__MAX_INDEX];
};

static struct data__file *data__files;
static int data__files_cnt;

#define data__for_each_file_start(i, d, s)  \
    for (i = s, d = &data__files[s];    \
         i < data__files_cnt;       \
         i++, d = &data__files[i])

#define data__for_each_file(i, d) data__for_each_file_start(i, d, 0)
#define data__for_each_file_new(i, d) data__for_each_file_start(i, d, 1)

static bool force;
static bool show_period;
static bool show_formula;
static bool show_baseline_only;
static unsigned int sort_compute = 1;

static s64 compute_wdiff_w1;
static s64 compute_wdiff_w2;

enum {
    COMPUTE_DELTA,
    COMPUTE_RATIO,
    COMPUTE_WEIGHTED_DIFF,
    COMPUTE_DELTA_ABS,
    COMPUTE_MAX,
};

const char *compute_names[COMPUTE_MAX] = {
    [COMPUTE_DELTA] = "delta",
    [COMPUTE_DELTA_ABS] = "delta-abs",
    [COMPUTE_RATIO] = "ratio",
    [COMPUTE_WEIGHTED_DIFF] = "wdiff",
};

static int compute = COMPUTE_DELTA_ABS;

static int compute_2_hpp[COMPUTE_MAX] = {
    [COMPUTE_DELTA]     = PERF_HPP_DIFF__DELTA,
    [COMPUTE_DELTA_ABS] = PERF_HPP_DIFF__DELTA_ABS,
    [COMPUTE_RATIO]     = PERF_HPP_DIFF__RATIO,
    [COMPUTE_WEIGHTED_DIFF] = PERF_HPP_DIFF__WEIGHTED_DIFF,
};

#define MAX_COL_WIDTH 70

static struct header_column {
    const char *name;
    int width;
} columns[PERF_HPP_DIFF__MAX_INDEX] = {
    [PERF_HPP_DIFF__BASELINE] = {
        .name  = "Baseline",
    },
    [PERF_HPP_DIFF__PERIOD] = {
        .name  = "Period",
        .width = 14,
    },
    [PERF_HPP_DIFF__PERIOD_BASELINE] = {
        .name  = "Base period",
        .width = 14,
    },
    [PERF_HPP_DIFF__DELTA] = {
        .name  = "Delta",
        .width = 7,
    },
    [PERF_HPP_DIFF__DELTA_ABS] = {
        .name  = "Delta Abs",
        .width = 7,
    },
    [PERF_HPP_DIFF__RATIO] = {
        .name  = "Ratio",
        .width = 14,
    },
    [PERF_HPP_DIFF__WEIGHTED_DIFF] = {
        .name  = "Weighted diff",
        .width = 14,
    },
    [PERF_HPP_DIFF__FORMULA] = {
        .name  = "Formula",
        .width = MAX_COL_WIDTH,
    }
};

static int setup_compute_opt_wdiff(char *opt)
{
    char *w1_str = opt;
    char *w2_str;

    int ret = -EINVAL;

    if (!opt)
        goto out;

    w2_str = strchr(opt, ',');
    if (!w2_str)
        goto out;

    *w2_str++ = 0x0;
    if (!*w2_str)
        goto out;

    compute_wdiff_w1 = strtol(w1_str, NULL, 10);
    compute_wdiff_w2 = strtol(w2_str, NULL, 10);

    if (!compute_wdiff_w1 || !compute_wdiff_w2)
        goto out;

    pr_debug("compute wdiff w1(%" PRId64 ") w2(%" PRId64 ")\n",
          compute_wdiff_w1, compute_wdiff_w2);

    ret = 0;

 out:
    if (ret)
        pr_err("Failed: wrong weight data, use 'wdiff:w1,w2'\n");

    return ret;
}

static int setup_compute_opt(char *opt)
{
    if (compute == COMPUTE_WEIGHTED_DIFF)
        return setup_compute_opt_wdiff(opt);

    if (opt) {
        pr_err("Failed: extra option specified '%s'", opt);
        return -EINVAL;
    }

    return 0;
}

static int setup_compute(const struct option *opt, const char *str,
             int unset __maybe_unused)
{
    int *cp = (int *) opt->value;
    char *cstr = (char *) str;
    char buf[50];
    unsigned i;
    char *option;

    if (!str) {
        *cp = COMPUTE_DELTA;
        return 0;
    }

    option = strchr(str, ':');
    if (option) {
        unsigned len = option++ - str;

        /*
         * The str data are not writeable, so we need
         * to use another buffer.
         */

        /* No option value is longer. */
        if (len >= sizeof(buf))
            return -EINVAL;

        strncpy(buf, str, len);
        buf[len] = 0x0;
        cstr = buf;
    }

    for (i = 0; i < COMPUTE_MAX; i++)
        if (!strcmp(cstr, compute_names[i])) {
            *cp = i;
            return setup_compute_opt(option);
        }

    pr_err("Failed: '%s' is not computation method "
           "(use 'delta','ratio' or 'wdiff')\n", str);
    return -EINVAL;
}

static double period_percent(struct hist_entry *he, u64 period)
{
    u64 total = hists__total_period(he->hists);

    return (period * 100.0) / total;
}

static double compute_delta(struct hist_entry *he, struct hist_entry *pair)
{
    double old_percent = period_percent(he, he->stat.period);
    double new_percent = period_percent(pair, pair->stat.period);

    pair->diff.period_ratio_delta = new_percent - old_percent;
    pair->diff.computed = true;
    return pair->diff.period_ratio_delta;
}

static double compute_ratio(struct hist_entry *he, struct hist_entry *pair)
{
    double old_period = he->stat.period ?: 1;
    double new_period = pair->stat.period;

    pair->diff.computed = true;
    pair->diff.period_ratio = new_period / old_period;
    return pair->diff.period_ratio;
}

static s64 compute_wdiff(struct hist_entry *he, struct hist_entry *pair)
{
    u64 old_period = he->stat.period;
    u64 new_period = pair->stat.period;

    pair->diff.computed = true;
    pair->diff.wdiff = new_period * compute_wdiff_w2 -
               old_period * compute_wdiff_w1;

    return pair->diff.wdiff;
}

static int formula_delta(struct hist_entry *he, struct hist_entry *pair,
             char *buf, size_t size)
{
    u64 he_total = he->hists->stats.total_period;
    u64 pair_total = pair->hists->stats.total_period;

    if (symbol_conf.filter_relative) {
        he_total = he->hists->stats.total_non_filtered_period;
        pair_total = pair->hists->stats.total_non_filtered_period;
    }
    return scnprintf(buf, size,
             "(%" PRIu64 " * 100 / %" PRIu64 ") - "
             "(%" PRIu64 " * 100 / %" PRIu64 ")",
             pair->stat.period, pair_total,
             he->stat.period, he_total);
}

static int formula_ratio(struct hist_entry *he, struct hist_entry *pair,
             char *buf, size_t size)
{
    double old_period = he->stat.period;
    double new_period = pair->stat.period;

    return scnprintf(buf, size, "%.0F / %.0F", new_period, old_period);
}

static int formula_wdiff(struct hist_entry *he, struct hist_entry *pair,
             char *buf, size_t size)
{
    u64 old_period = he->stat.period;
    u64 new_period = pair->stat.period;

    return scnprintf(buf, size,
          "(%" PRIu64 " * " "%" PRId64 ") - (%" PRIu64 " * " "%" PRId64 ")",
          new_period, compute_wdiff_w2, old_period, compute_wdiff_w1);
}

static int formula_fprintf(struct hist_entry *he, struct hist_entry *pair,
               char *buf, size_t size)
{
    switch (compute) {
    case COMPUTE_DELTA:
    case COMPUTE_DELTA_ABS:
        return formula_delta(he, pair, buf, size);
    case COMPUTE_RATIO:
        return formula_ratio(he, pair, buf, size);
    case COMPUTE_WEIGHTED_DIFF:
        return formula_wdiff(he, pair, buf, size);
    default:
        BUG_ON(1);
    }

    return -1;
}

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;
    struct hists *hists = evsel__hists(evsel);
    int ret = -1;

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

    if (!hists__add_entry(hists, &al, NULL, NULL, NULL, sample, true)) {
        pr_warning("problem incrementing symbol period, skipping event\n");
        goto out_put;
    }

    /*
     * The total_period is updated here before going to the output
     * tree since normally only the baseline hists will call
     * hists__output_resort() and precompute needs the total
     * period in order to sort entries by percentage delta.
     */
    hists->stats.total_period += sample->period;
    if (!al.filtered)
        hists->stats.total_non_filtered_period += sample->period;
    ret = 0;
out_put:
    addr_location__put(&al);
    return ret;
}

static struct perf_tool tool = {
    .sample = diff__process_sample_event,
    .mmap   = perf_event__process_mmap,
    .mmap2  = perf_event__process_mmap2,
    .comm   = perf_event__process_comm,
    .exit   = perf_event__process_exit,
    .fork   = perf_event__process_fork,
    .lost   = perf_event__process_lost,
    .namespaces = perf_event__process_namespaces,
    .ordered_events = true,
    .ordering_requires_timestamps = true,
};

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

    evlist__for_each_entry(evlist, e) {
        if (perf_evsel__match2(evsel, e))
            return e;
    }

    return NULL;
}

static void perf_evlist__collapse_resort(struct perf_evlist *evlist)
{
    struct perf_evsel *evsel;

    evlist__for_each_entry(evlist, evsel) {
        struct hists *hists = evsel__hists(evsel);

        hists__collapse_resort(hists, NULL);
    }
}

static struct data__file *fmt_to_data_file(struct perf_hpp_fmt *fmt)
{
    struct diff_hpp_fmt *dfmt = container_of(fmt, struct diff_hpp_fmt, fmt);
    void *ptr = dfmt - dfmt->idx;
    struct data__file *d = container_of(ptr, struct data__file, fmt);

    return d;
}

static struct hist_entry*
get_pair_data(struct hist_entry *he, struct data__file *d)
{
    if (hist_entry__has_pairs(he)) {
        struct hist_entry *pair;

        list_for_each_entry(pair, &he->pairs.head, pairs.node)
            if (pair->hists == d->hists)
                return pair;
    }

    return NULL;
}

static struct hist_entry*
get_pair_fmt(struct hist_entry *he, struct diff_hpp_fmt *dfmt)
{
    struct data__file *d = fmt_to_data_file(&dfmt->fmt);

    return get_pair_data(he, d);
}

static void hists__baseline_only(struct hists *hists)
{
    struct rb_root *root;
    struct rb_node *next;

    if (hists__has(hists, need_collapse))
        root = &hists->entries_collapsed;
    else
        root = hists->entries_in;

    next = rb_first(root);
    while (next != NULL) {
        struct hist_entry *he = rb_entry(next, struct hist_entry, rb_node_in);

        next = rb_next(&he->rb_node_in);
        if (!hist_entry__next_pair(he)) {
            rb_erase(&he->rb_node_in, root);
            hist_entry__delete(he);
        }
    }
}

static void hists__precompute(struct hists *hists)
{
    struct rb_root *root;
    struct rb_node *next;

    if (hists__has(hists, need_collapse))
        root = &hists->entries_collapsed;
    else
        root = hists->entries_in;

    next = rb_first(root);
    while (next != NULL) {
        struct hist_entry *he, *pair;
        struct data__file *d;
        int i;

        he   = rb_entry(next, struct hist_entry, rb_node_in);
        next = rb_next(&he->rb_node_in);

        data__for_each_file_new(i, d) {
            pair = get_pair_data(he, d);
            if (!pair)
                continue;

            switch (compute) {
            case COMPUTE_DELTA:
            case COMPUTE_DELTA_ABS:
                compute_delta(he, pair);
                break;
            case COMPUTE_RATIO:
                compute_ratio(he, pair);
                break;
            case COMPUTE_WEIGHTED_DIFF:
                compute_wdiff(he, pair);
                break;
            default:
                BUG_ON(1);
            }
        }
    }
}

static int64_t cmp_doubles(double l, double r)
{
    if (l > r)
        return -1;
    else if (l < r)
        return 1;
    else
        return 0;
}

static int64_t
__hist_entry__cmp_compute(struct hist_entry *left, struct hist_entry *right,
            int c)
{
    switch (c) {
    case COMPUTE_DELTA:
    {
        double l = left->diff.period_ratio_delta;
        double r = right->diff.period_ratio_delta;

        return cmp_doubles(l, r);
    }
    case COMPUTE_DELTA_ABS:
    {
        double l = fabs(left->diff.period_ratio_delta);
        double r = fabs(right->diff.period_ratio_delta);

        return cmp_doubles(l, r);
    }
    case COMPUTE_RATIO:
    {
        double l = left->diff.period_ratio;
        double r = right->diff.period_ratio;

        return cmp_doubles(l, r);
    }
    case COMPUTE_WEIGHTED_DIFF:
    {
        s64 l = left->diff.wdiff;
        s64 r = right->diff.wdiff;

        return r - l;
    }
    default:
        BUG_ON(1);
    }

    return 0;
}

static int64_t
hist_entry__cmp_compute(struct hist_entry *left, struct hist_entry *right,
            int c, int sort_idx)
{
    bool pairs_left  = hist_entry__has_pairs(left);
    bool pairs_right = hist_entry__has_pairs(right);
    struct hist_entry *p_right, *p_left;

    if (!pairs_left && !pairs_right)
        return 0;

    if (!pairs_left || !pairs_right)
        return pairs_left ? -1 : 1;

    p_left  = get_pair_data(left,  &data__files[sort_idx]);
    p_right = get_pair_data(right, &data__files[sort_idx]);

    if (!p_left && !p_right)
        return 0;

    if (!p_left || !p_right)
        return p_left ? -1 : 1;

    /*
     * We have 2 entries of same kind, let's
     * make the data comparison.
     */
    return __hist_entry__cmp_compute(p_left, p_right, c);
}

static int64_t
hist_entry__cmp_compute_idx(struct hist_entry *left, struct hist_entry *right,
                int c, int sort_idx)
{
    struct hist_entry *p_right, *p_left;

    p_left  = get_pair_data(left,  &data__files[sort_idx]);
    p_right = get_pair_data(right, &data__files[sort_idx]);

    if (!p_left && !p_right)
        return 0;

    if (!p_left || !p_right)
        return p_left ? -1 : 1;

    if (c != COMPUTE_DELTA && c != COMPUTE_DELTA_ABS) {
        /*
         * The delta can be computed without the baseline, but
         * others are not.  Put those entries which have no
         * values below.
         */
        if (left->dummy && right->dummy)
            return 0;

        if (left->dummy || right->dummy)
            return left->dummy ? 1 : -1;
    }

    return __hist_entry__cmp_compute(p_left, p_right, c);
}

static int64_t
hist_entry__cmp_nop(struct perf_hpp_fmt *fmt __maybe_unused,
            struct hist_entry *left __maybe_unused,
            struct hist_entry *right __maybe_unused)
{
    return 0;
}

static int64_t
hist_entry__cmp_baseline(struct perf_hpp_fmt *fmt __maybe_unused,
             struct hist_entry *left, struct hist_entry *right)
{
    if (left->stat.period == right->stat.period)
        return 0;
    return left->stat.period > right->stat.period ? 1 : -1;
}

static int64_t
hist_entry__cmp_delta(struct perf_hpp_fmt *fmt,
              struct hist_entry *left, struct hist_entry *right)
{
    struct data__file *d = fmt_to_data_file(fmt);

    return hist_entry__cmp_compute(right, left, COMPUTE_DELTA, d->idx);
}

static int64_t
hist_entry__cmp_delta_abs(struct perf_hpp_fmt *fmt,
              struct hist_entry *left, struct hist_entry *right)
{
    struct data__file *d = fmt_to_data_file(fmt);

    return hist_entry__cmp_compute(right, left, COMPUTE_DELTA_ABS, d->idx);
}

static int64_t
hist_entry__cmp_ratio(struct perf_hpp_fmt *fmt,
              struct hist_entry *left, struct hist_entry *right)
{
    struct data__file *d = fmt_to_data_file(fmt);

    return hist_entry__cmp_compute(right, left, COMPUTE_RATIO, d->idx);
}

static int64_t
hist_entry__cmp_wdiff(struct perf_hpp_fmt *fmt,
              struct hist_entry *left, struct hist_entry *right)
{
    struct data__file *d = fmt_to_data_file(fmt);

    return hist_entry__cmp_compute(right, left, COMPUTE_WEIGHTED_DIFF, d->idx);
}

static int64_t
hist_entry__cmp_delta_idx(struct perf_hpp_fmt *fmt __maybe_unused,
              struct hist_entry *left, struct hist_entry *right)
{
    return hist_entry__cmp_compute_idx(right, left, COMPUTE_DELTA,
                       sort_compute);
}

static int64_t
hist_entry__cmp_delta_abs_idx(struct perf_hpp_fmt *fmt __maybe_unused,
                  struct hist_entry *left, struct hist_entry *right)
{
    return hist_entry__cmp_compute_idx(right, left, COMPUTE_DELTA_ABS,
                       sort_compute);
}

static int64_t
hist_entry__cmp_ratio_idx(struct perf_hpp_fmt *fmt __maybe_unused,
              struct hist_entry *left, struct hist_entry *right)
{
    return hist_entry__cmp_compute_idx(right, left, COMPUTE_RATIO,
                       sort_compute);
}

static int64_t
hist_entry__cmp_wdiff_idx(struct perf_hpp_fmt *fmt __maybe_unused,
              struct hist_entry *left, struct hist_entry *right)
{
    return hist_entry__cmp_compute_idx(right, left, COMPUTE_WEIGHTED_DIFF,
                       sort_compute);
}

static void hists__process(struct hists *hists)
{
    if (show_baseline_only)
        hists__baseline_only(hists);

    hists__precompute(hists);
    hists__output_resort(hists, NULL);

    hists__fprintf(hists, !quiet, 0, 0, 0, stdout,
               symbol_conf.use_callchain);
}

static void data__fprintf(void)
{
    struct data__file *d;
    int i;

    fprintf(stdout, "# Data files:\n");

    data__for_each_file(i, d)
        fprintf(stdout, "#  [%d] %s %s\n",
            d->idx, d->data.file.path,
            !d->idx ? "(Baseline)" : "");

    fprintf(stdout, "#\n");
}

static void data_process(void)
{
    struct perf_evlist *evlist_base = data__files[0].session->evlist;
    struct perf_evsel *evsel_base;
    bool first = true;

    evlist__for_each_entry(evlist_base, evsel_base) {
        struct hists *hists_base = evsel__hists(evsel_base);
        struct data__file *d;
        int i;

        data__for_each_file_new(i, d) {
            struct perf_evlist *evlist = d->session->evlist;
            struct perf_evsel *evsel;
            struct hists *hists;

            evsel = evsel_match(evsel_base, evlist);
            if (!evsel)
                continue;

            hists = evsel__hists(evsel);
            d->hists = hists;

            hists__match(hists_base, hists);

            if (!show_baseline_only)
                hists__link(hists_base, hists);
        }

        if (!quiet) {
            fprintf(stdout, "%s# Event '%s'\n#\n", first ? "" : "\n",
                perf_evsel__name(evsel_base));
        }

        first = false;

        if (verbose > 0 || ((data__files_cnt > 2) && !quiet))
            data__fprintf();

        /* Don't sort callchain for perf diff */
        perf_evsel__reset_sample_bit(evsel_base, CALLCHAIN);

        hists__process(hists_base);
    }
}

static void data__free(struct data__file *d)
{
    int col;

    for (col = 0; col < PERF_HPP_DIFF__MAX_INDEX; col++) {
        struct diff_hpp_fmt *fmt = &d->fmt[col];

        zfree(&fmt->header);
    }
}

static int __cmd_diff(void)
{
    struct data__file *d;
    int ret = -EINVAL, i;

    data__for_each_file(i, d) {
        d->session = perf_session__new(&d->data, false, &tool);
        if (!d->session) {
            pr_err("Failed to open %s\n", d->data.file.path);
            ret = -1;
            goto out_delete;
        }

        ret = perf_session__process_events(d->session);
        if (ret) {
            pr_err("Failed to process %s\n", d->data.file.path);
            goto out_delete;
        }

        perf_evlist__collapse_resort(d->session->evlist);
    }

    data_process();

 out_delete:
    data__for_each_file(i, d) {
        perf_session__delete(d->session);
        data__free(d);
    }

    free(data__files);
    return ret;
}

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('q', "quiet", &quiet, "Do not show any message"),
    OPT_BOOLEAN('b', "baseline-only", &show_baseline_only,
            "Show only items with match in baseline"),
    OPT_CALLBACK('c', "compute", &compute,
             "delta,delta-abs,ratio,wdiff:w1,w2 (default delta-abs)",
             "Entries differential computation selection",
             setup_compute),
    OPT_BOOLEAN('p', "period", &show_period,
            "Show period values."),
    OPT_BOOLEAN('F', "formula", &show_formula,
            "Show formula."),
    OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
            "dump raw trace in ASCII"),
    OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
    OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
           "file", "kallsyms pathname"),
    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, cpu, srcline, ..."
           " Please refer the man page for the complete list."),
    OPT_STRING_NOEMPTY('t', "field-separator", &symbol_conf.field_sep, "separator",
           "separator for columns, no spaces will be added between "
           "columns '.' is reserved."),
    OPT_CALLBACK(0, "symfs", NULL, "directory",
             "Look for files with symbols relative to this directory",
             symbol__config_symfs),
    OPT_UINTEGER('o', "order", &sort_compute, "Specify compute sorting."),
    OPT_CALLBACK(0, "percentage", NULL, "relative|absolute",
             "How to display percentage of filtered entries", parse_filter_percentage),
    OPT_END()
};

static double baseline_percent(struct hist_entry *he)
{
    u64 total = hists__total_period(he->hists);

    return 100.0 * he->stat.period / total;
}

static int hpp__color_baseline(struct perf_hpp_fmt *fmt,
                   struct perf_hpp *hpp, struct hist_entry *he)
{
    struct diff_hpp_fmt *dfmt =
        container_of(fmt, struct diff_hpp_fmt, fmt);
    double percent = baseline_percent(he);
    char pfmt[20] = " ";

    if (!he->dummy) {
        scnprintf(pfmt, 20, "%%%d.2f%%%%", dfmt->header_width - 1);
        return percent_color_snprintf(hpp->buf, hpp->size,
                          pfmt, percent);
    } else
        return scnprintf(hpp->buf, hpp->size, "%*s",
                 dfmt->header_width, pfmt);
}

static int hpp__entry_baseline(struct hist_entry *he, char *buf, size_t size)
{
    double percent = baseline_percent(he);
    const char *fmt = symbol_conf.field_sep ? "%.2f" : "%6.2f%%";
    int ret = 0;

    if (!he->dummy)
        ret = scnprintf(buf, size, fmt, percent);

    return ret;
}

static int __hpp__color_compare(struct perf_hpp_fmt *fmt,
                struct perf_hpp *hpp, struct hist_entry *he,
                int comparison_method)
{
    struct diff_hpp_fmt *dfmt =
        container_of(fmt, struct diff_hpp_fmt, fmt);
    struct hist_entry *pair = get_pair_fmt(he, dfmt);
    double diff;
    s64 wdiff;
    char pfmt[20] = " ";

    if (!pair)
        goto no_print;

    switch (comparison_method) {
    case COMPUTE_DELTA:
        if (pair->diff.computed)
            diff = pair->diff.period_ratio_delta;
        else
            diff = compute_delta(he, pair);

        scnprintf(pfmt, 20, "%%%+d.2f%%%%", dfmt->header_width - 1);
        return percent_color_snprintf(hpp->buf, hpp->size,
                    pfmt, diff);
    case COMPUTE_RATIO:
        if (he->dummy)
            goto dummy_print;
        if (pair->diff.computed)
            diff = pair->diff.period_ratio;
        else
            diff = compute_ratio(he, pair);

        scnprintf(pfmt, 20, "%%%d.6f", dfmt->header_width);
        return value_color_snprintf(hpp->buf, hpp->size,
                    pfmt, diff);
    case COMPUTE_WEIGHTED_DIFF:
        if (he->dummy)
            goto dummy_print;
        if (pair->diff.computed)
            wdiff = pair->diff.wdiff;
        else
            wdiff = compute_wdiff(he, pair);

        scnprintf(pfmt, 20, "%%14ld", dfmt->header_width);
        return color_snprintf(hpp->buf, hpp->size,
                get_percent_color(wdiff),
                pfmt, wdiff);
    default:
        BUG_ON(1);
    }
dummy_print:
    return scnprintf(hpp->buf, hpp->size, "%*s",
            dfmt->header_width, "N/A");
no_print:
    return scnprintf(hpp->buf, hpp->size, "%*s",
            dfmt->header_width, pfmt);
}

static int hpp__color_delta(struct perf_hpp_fmt *fmt,
            struct perf_hpp *hpp, struct hist_entry *he)
{
    return __hpp__color_compare(fmt, hpp, he, COMPUTE_DELTA);
}

static int hpp__color_ratio(struct perf_hpp_fmt *fmt,
            struct perf_hpp *hpp, struct hist_entry *he)
{
    return __hpp__color_compare(fmt, hpp, he, COMPUTE_RATIO);
}

static int hpp__color_wdiff(struct perf_hpp_fmt *fmt,
            struct perf_hpp *hpp, struct hist_entry *he)
{
    return __hpp__color_compare(fmt, hpp, he, COMPUTE_WEIGHTED_DIFF);
}

static void
hpp__entry_unpair(struct hist_entry *he, int idx, char *buf, size_t size)
{
    switch (idx) {
    case PERF_HPP_DIFF__PERIOD_BASELINE:
        scnprintf(buf, size, "%" PRIu64, he->stat.period);
        break;

    default:
        break;
    }
}

static void
hpp__entry_pair(struct hist_entry *he, struct hist_entry *pair,
        int idx, char *buf, size_t size)
{
    double diff;
    double ratio;
    s64 wdiff;

    switch (idx) {
    case PERF_HPP_DIFF__DELTA:
    case PERF_HPP_DIFF__DELTA_ABS:
        if (pair->diff.computed)
            diff = pair->diff.period_ratio_delta;
        else
            diff = compute_delta(he, pair);

        scnprintf(buf, size, "%+4.2F%%", diff);
        break;

    case PERF_HPP_DIFF__RATIO:
        /* No point for ratio number if we are dummy.. */
        if (he->dummy) {
            scnprintf(buf, size, "N/A");
            break;
        }

        if (pair->diff.computed)
            ratio = pair->diff.period_ratio;
        else
            ratio = compute_ratio(he, pair);

        if (ratio > 0.0)
            scnprintf(buf, size, "%14.6F", ratio);
        break;

    case PERF_HPP_DIFF__WEIGHTED_DIFF:
        /* No point for wdiff number if we are dummy.. */
        if (he->dummy) {
            scnprintf(buf, size, "N/A");
            break;
        }

        if (pair->diff.computed)
            wdiff = pair->diff.wdiff;
        else
            wdiff = compute_wdiff(he, pair);

        if (wdiff != 0)
            scnprintf(buf, size, "%14ld", wdiff);
        break;

    case PERF_HPP_DIFF__FORMULA:
        formula_fprintf(he, pair, buf, size);
        break;

    case PERF_HPP_DIFF__PERIOD:
        scnprintf(buf, size, "%" PRIu64, pair->stat.period);
        break;

    default:
        BUG_ON(1);
    };
}

static void
__hpp__entry_global(struct hist_entry *he, struct diff_hpp_fmt *dfmt,
            char *buf, size_t size)
{
    struct hist_entry *pair = get_pair_fmt(he, dfmt);
    int idx = dfmt->idx;

    /* baseline is special */
    if (idx == PERF_HPP_DIFF__BASELINE)
        hpp__entry_baseline(he, buf, size);
    else {
        if (pair)
            hpp__entry_pair(he, pair, idx, buf, size);
        else
            hpp__entry_unpair(he, idx, buf, size);
    }
}

static int hpp__entry_global(struct perf_hpp_fmt *_fmt, struct perf_hpp *hpp,
                 struct hist_entry *he)
{
    struct diff_hpp_fmt *dfmt =
        container_of(_fmt, struct diff_hpp_fmt, fmt);
    char buf[MAX_COL_WIDTH] = " ";

    __hpp__entry_global(he, dfmt, buf, MAX_COL_WIDTH);

    if (symbol_conf.field_sep)
        return scnprintf(hpp->buf, hpp->size, "%s", buf);
    else
        return scnprintf(hpp->buf, hpp->size, "%*s",
                 dfmt->header_width, buf);
}

static int hpp__header(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp,
               struct hists *hists __maybe_unused,
               int line __maybe_unused,
               int *span __maybe_unused)
{
    struct diff_hpp_fmt *dfmt =
        container_of(fmt, struct diff_hpp_fmt, fmt);

    BUG_ON(!dfmt->header);
    return scnprintf(hpp->buf, hpp->size, dfmt->header);
}

static int hpp__width(struct perf_hpp_fmt *fmt,
              struct perf_hpp *hpp __maybe_unused,
              struct hists *hists __maybe_unused)
{
    struct diff_hpp_fmt *dfmt =
        container_of(fmt, struct diff_hpp_fmt, fmt);

    BUG_ON(dfmt->header_width <= 0);
    return dfmt->header_width;
}

static void init_header(struct data__file *d, struct diff_hpp_fmt *dfmt)
{
#define MAX_HEADER_NAME 100
    char buf_indent[MAX_HEADER_NAME];
    char buf[MAX_HEADER_NAME];
    const char *header = NULL;
    int width = 0;

    BUG_ON(dfmt->idx >= PERF_HPP_DIFF__MAX_INDEX);
    header = columns[dfmt->idx].name;
    width  = columns[dfmt->idx].width;

    /* Only our defined HPP fmts should appear here. */
    BUG_ON(!header);

    if (data__files_cnt > 2)
        scnprintf(buf, MAX_HEADER_NAME, "%s/%d", header, d->idx);

#define NAME (data__files_cnt > 2 ? buf : header)
    dfmt->header_width = width;
    width = (int) strlen(NAME);
    if (dfmt->header_width < width)
        dfmt->header_width = width;

    scnprintf(buf_indent, MAX_HEADER_NAME, "%*s",
          dfmt->header_width, NAME);

    dfmt->header = strdup(buf_indent);
#undef MAX_HEADER_NAME
#undef NAME
}

static void data__hpp_register(struct data__file *d, int idx)
{
    struct diff_hpp_fmt *dfmt = &d->fmt[idx];
    struct perf_hpp_fmt *fmt = &dfmt->fmt;

    dfmt->idx = idx;

    fmt->header = hpp__header;
    fmt->width  = hpp__width;
    fmt->entry  = hpp__entry_global;
    fmt->cmp    = hist_entry__cmp_nop;
    fmt->collapse = hist_entry__cmp_nop;

    /* TODO more colors */
    switch (idx) {
    case PERF_HPP_DIFF__BASELINE:
        fmt->color = hpp__color_baseline;
        fmt->sort  = hist_entry__cmp_baseline;
        break;
    case PERF_HPP_DIFF__DELTA:
        fmt->color = hpp__color_delta;
        fmt->sort  = hist_entry__cmp_delta;
        break;
    case PERF_HPP_DIFF__RATIO:
        fmt->color = hpp__color_ratio;
        fmt->sort  = hist_entry__cmp_ratio;
        break;
    case PERF_HPP_DIFF__WEIGHTED_DIFF:
        fmt->color = hpp__color_wdiff;
        fmt->sort  = hist_entry__cmp_wdiff;
        break;
    case PERF_HPP_DIFF__DELTA_ABS:
        fmt->color = hpp__color_delta;
        fmt->sort  = hist_entry__cmp_delta_abs;
        break;
    default:
        fmt->sort  = hist_entry__cmp_nop;
        break;
    }

    init_header(d, dfmt);
    perf_hpp__column_register(fmt);
    perf_hpp__register_sort_field(fmt);
}

static int ui_init(void)
{
    struct data__file *d;
    struct perf_hpp_fmt *fmt;
    int i;

    data__for_each_file(i, d) {

        /*
         * Baseline or compute realted columns:
         *
         *   PERF_HPP_DIFF__BASELINE
         *   PERF_HPP_DIFF__DELTA
         *   PERF_HPP_DIFF__RATIO
         *   PERF_HPP_DIFF__WEIGHTED_DIFF
         */
        data__hpp_register(d, i ? compute_2_hpp[compute] :
                      PERF_HPP_DIFF__BASELINE);

        /*
         * And the rest:
         *
         * PERF_HPP_DIFF__FORMULA
         * PERF_HPP_DIFF__PERIOD
         * PERF_HPP_DIFF__PERIOD_BASELINE
         */
        if (show_formula && i)
            data__hpp_register(d, PERF_HPP_DIFF__FORMULA);

        if (show_period)
            data__hpp_register(d, i ? PERF_HPP_DIFF__PERIOD :
                          PERF_HPP_DIFF__PERIOD_BASELINE);
    }

    if (!sort_compute)
        return 0;

    /*
     * Prepend an fmt to sort on columns at 'sort_compute' first.
     * This fmt is added only to the sort list but not to the
     * output fields list.
     *
     * Note that this column (data) can be compared twice - one
     * for this 'sort_compute' fmt and another for the normal
     * diff_hpp_fmt.  But it shouldn't a problem as most entries
     * will be sorted out by first try or baseline and comparing
     * is not a costly operation.
     */
    fmt = zalloc(sizeof(*fmt));
    if (fmt == NULL) {
        pr_err("Memory allocation failed\n");
        return -1;
    }

    fmt->cmp      = hist_entry__cmp_nop;
    fmt->collapse = hist_entry__cmp_nop;

    switch (compute) {
    case COMPUTE_DELTA:
        fmt->sort = hist_entry__cmp_delta_idx;
        break;
    case COMPUTE_RATIO:
        fmt->sort = hist_entry__cmp_ratio_idx;
        break;
    case COMPUTE_WEIGHTED_DIFF:
        fmt->sort = hist_entry__cmp_wdiff_idx;
        break;
    case COMPUTE_DELTA_ABS:
        fmt->sort = hist_entry__cmp_delta_abs_idx;
        break;
    default:
        BUG_ON(1);
    }

    perf_hpp__prepend_sort_field(fmt);
    return 0;
}

static int data_init(int argc, const char **argv)
{
    struct data__file *d;
    static const char *defaults[] = {
        "perf.data.old",
        "perf.data",
    };
    bool use_default = true;
    int i;

    data__files_cnt = 2;

    if (argc) {
        if (argc == 1)
            defaults[1] = argv[0];
        else {
            data__files_cnt = argc;
            use_default = false;
        }
    } else if (perf_guest) {
        defaults[0] = "perf.data.host";
        defaults[1] = "perf.data.guest";
    }

    if (sort_compute >= (unsigned int) data__files_cnt) {
        pr_err("Order option out of limit.\n");
        return -EINVAL;
    }

    data__files = zalloc(sizeof(*data__files) * data__files_cnt);
    if (!data__files)
        return -ENOMEM;

    data__for_each_file(i, d) {
        struct perf_data *data = &d->data;

        data->file.path = use_default ? defaults[i] : argv[i];
        data->mode      = PERF_DATA_MODE_READ,
        data->force     = force,

        d->idx  = i;
    }

    return 0;
}

static int diff__config(const char *var, const char *value,
            void *cb __maybe_unused)
{
    if (!strcmp(var, "diff.order")) {
        int ret;
        if (perf_config_int(&ret, var, value) < 0)
            return -1;
        sort_compute = ret;
        return 0;
    }
    if (!strcmp(var, "diff.compute")) {
        if (!strcmp(value, "delta")) {
            compute = COMPUTE_DELTA;
        } else if (!strcmp(value, "delta-abs")) {
            compute = COMPUTE_DELTA_ABS;
        } else if (!strcmp(value, "ratio")) {
            compute = COMPUTE_RATIO;
        } else if (!strcmp(value, "wdiff")) {
            compute = COMPUTE_WEIGHTED_DIFF;
        } else {
            pr_err("Invalid compute method: %s\n", value);
            return -1;
        }
    }

    return 0;
}

int cmd_diff(int argc, const char **argv)
{
    int ret = hists__init();

    if (ret < 0)
        return ret;

    perf_config(diff__config, NULL);

    argc = parse_options(argc, argv, options, diff_usage, 0);

    if (quiet)
        perf_quiet_option();

    if (symbol__init(NULL) < 0)
        return -1;

    if (data_init(argc, argv) < 0)
        return -1;

    if (ui_init() < 0)
        return -1;

    sort__mode = SORT_MODE__DIFF;

    if (setup_sorting(NULL) < 0)
        usage_with_options(diff_usage, options);

    setup_pager();

    sort__setup_elide(NULL);

    return __cmd_diff();
}