// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
 */

#define _GNU_SOURCE
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <time.h>

#include "osnoise.h"

struct osnoise_hist_cpu {
        int                     *samples;
        int                     count;

        unsigned long long      min_sample;
        unsigned long long      sum_sample;
        unsigned long long      max_sample;

};

struct osnoise_hist_data {
        struct tracefs_hist     *trace_hist;
        struct osnoise_hist_cpu *hist;
        int                     entries;
        int                     bucket_size;
        int                     nr_cpus;
};

/*
 * osnoise_free_histogram - free runtime data
 */
static void
osnoise_free_histogram(struct osnoise_hist_data *data)
{
        int cpu;

        /* one histogram for IRQ and one for thread, per CPU */
        for (cpu = 0; cpu < data->nr_cpus; cpu++) {
                if (data->hist[cpu].samples)
                        free(data->hist[cpu].samples);
        }

        /* one set of histograms per CPU */
        if (data->hist)
                free(data->hist);

        free(data);
}

static void osnoise_free_hist_tool(struct osnoise_tool *tool)
{
        osnoise_free_histogram(tool->data);
}

/*
 * osnoise_alloc_histogram - alloc runtime data
 */
static struct osnoise_hist_data
*osnoise_alloc_histogram(int nr_cpus, int entries, int bucket_size)
{
        struct osnoise_hist_data *data;
        int cpu;

        data = calloc(1, sizeof(*data));
        if (!data)
                return NULL;

        data->entries = entries;
        data->bucket_size = bucket_size;
        data->nr_cpus = nr_cpus;

        data->hist = calloc(1, sizeof(*data->hist) * nr_cpus);
        if (!data->hist)
                goto cleanup;

        for (cpu = 0; cpu < nr_cpus; cpu++) {
                data->hist[cpu].samples = calloc(1, sizeof(*data->hist->samples) * (entries + 1));
                if (!data->hist[cpu].samples)
                        goto cleanup;
        }

        /* set the min to max */
        for (cpu = 0; cpu < nr_cpus; cpu++)
                data->hist[cpu].min_sample = ~0;

        return data;

cleanup:
        osnoise_free_histogram(data);
        return NULL;
}

static void osnoise_hist_update_multiple(struct osnoise_tool *tool, int cpu,
                                         unsigned long long duration, int count)
{
        struct osnoise_params *params = to_osnoise_params(tool->params);
        struct osnoise_hist_data *data = tool->data;
        unsigned long long total_duration;
        int entries = data->entries;
        int bucket;
        int *hist;

        if (params->common.output_divisor)
                duration = duration / params->common.output_divisor;

        bucket = duration / data->bucket_size;

        total_duration = duration * count;

        hist = data->hist[cpu].samples;
        data->hist[cpu].count += count;
        update_min(&data->hist[cpu].min_sample, &duration);
        update_sum(&data->hist[cpu].sum_sample, &total_duration);
        update_max(&data->hist[cpu].max_sample, &duration);

        if (bucket < entries)
                hist[bucket] += count;
        else
                hist[entries] += count;
}

/*
 * osnoise_destroy_trace_hist - disable events used to collect histogram
 */
static void osnoise_destroy_trace_hist(struct osnoise_tool *tool)
{
        struct osnoise_hist_data *data = tool->data;

        tracefs_hist_pause(tool->trace.inst, data->trace_hist);
        tracefs_hist_destroy(tool->trace.inst, data->trace_hist);
}

/*
 * osnoise_init_trace_hist - enable events used to collect histogram
 */
static int osnoise_init_trace_hist(struct osnoise_tool *tool)
{
        struct osnoise_params *params = to_osnoise_params(tool->params);
        struct osnoise_hist_data *data = tool->data;
        int bucket_size;
        char buff[128];
        int retval = 0;

        /*
         * Set the size of the bucket.
         */
        bucket_size = params->common.output_divisor * params->common.hist.bucket_size;
        snprintf(buff, sizeof(buff), "duration.buckets=%d", bucket_size);

        data->trace_hist = tracefs_hist_alloc(tool->trace.tep, "osnoise", "sample_threshold",
                        buff, TRACEFS_HIST_KEY_NORMAL);
        if (!data->trace_hist)
                return 1;

        retval = tracefs_hist_add_key(data->trace_hist, "cpu", 0);
        if (retval)
                goto out_err;

        retval = tracefs_hist_start(tool->trace.inst, data->trace_hist);
        if (retval)
                goto out_err;

        return 0;

out_err:
        osnoise_destroy_trace_hist(tool);
        return 1;
}

/*
 * osnoise_read_trace_hist - parse histogram file and file osnoise histogram
 */
static void osnoise_read_trace_hist(struct osnoise_tool *tool)
{
        struct osnoise_hist_data *data = tool->data;
        long long cpu, counter, duration;
        char *content, *position;

        tracefs_hist_pause(tool->trace.inst, data->trace_hist);

        content = tracefs_event_file_read(tool->trace.inst, "osnoise",
                                          "sample_threshold",
                                          "hist", NULL);
        if (!content)
                return;

        position = content;
        while (true) {
                position = strstr(position, "duration: ~");
                if (!position)
                        break;
                position += strlen("duration: ~");
                duration = get_llong_from_str(position);
                if (duration == -1)
                        err_msg("error reading duration from histogram\n");

                position = strstr(position, "cpu:");
                if (!position)
                        break;
                position += strlen("cpu: ");
                cpu = get_llong_from_str(position);
                if (cpu == -1)
                        err_msg("error reading cpu from histogram\n");

                position = strstr(position, "hitcount:");
                if (!position)
                        break;
                position += strlen("hitcount: ");
                counter = get_llong_from_str(position);
                if (counter == -1)
                        err_msg("error reading counter from histogram\n");

                osnoise_hist_update_multiple(tool, cpu, duration, counter);
        }
        free(content);
}

/*
 * osnoise_hist_header - print the header of the tracer to the output
 */
static void osnoise_hist_header(struct osnoise_tool *tool)
{
        struct osnoise_params *params = to_osnoise_params(tool->params);
        struct osnoise_hist_data *data = tool->data;
        struct trace_seq *s = tool->trace.seq;
        char duration[26];
        int cpu;

        if (params->common.hist.no_header)
                return;

        get_duration(tool->start_time, duration, sizeof(duration));
        trace_seq_printf(s, "# RTLA osnoise histogram\n");
        trace_seq_printf(s, "# Time unit is %s (%s)\n",
                        params->common.output_divisor == 1 ? "nanoseconds" : "microseconds",
                        params->common.output_divisor == 1 ? "ns" : "us");

        trace_seq_printf(s, "# Duration: %s\n", duration);

        if (!params->common.hist.no_index)
                trace_seq_printf(s, "Index");

        for_each_monitored_cpu(cpu, data->nr_cpus, &params->common) {

                if (!data->hist[cpu].count)
                        continue;

                trace_seq_printf(s, "   CPU-%03d", cpu);
        }
        trace_seq_printf(s, "\n");

        trace_seq_do_printf(s);
        trace_seq_reset(s);
}

/*
 * osnoise_print_summary - print the summary of the hist data to the output
 */
static void
osnoise_print_summary(struct osnoise_params *params,
                       struct trace_instance *trace,
                       struct osnoise_hist_data *data)
{
        int cpu;

        if (params->common.hist.no_summary)
                return;

        if (!params->common.hist.no_index)
                trace_seq_printf(trace->seq, "count:");

        for_each_monitored_cpu(cpu, data->nr_cpus, &params->common) {

                if (!data->hist[cpu].count)
                        continue;

                trace_seq_printf(trace->seq, "%9d ", data->hist[cpu].count);
        }
        trace_seq_printf(trace->seq, "\n");

        if (!params->common.hist.no_index)
                trace_seq_printf(trace->seq, "min:  ");

        for_each_monitored_cpu(cpu, data->nr_cpus, &params->common) {

                if (!data->hist[cpu].count)
                        continue;

                trace_seq_printf(trace->seq, "%9llu ",  data->hist[cpu].min_sample);

        }
        trace_seq_printf(trace->seq, "\n");

        if (!params->common.hist.no_index)
                trace_seq_printf(trace->seq, "avg:  ");

        for_each_monitored_cpu(cpu, data->nr_cpus, &params->common) {

                if (!data->hist[cpu].count)
                        continue;

                if (data->hist[cpu].count)
                        trace_seq_printf(trace->seq, "%9.2f ",
                                ((double) data->hist[cpu].sum_sample) / data->hist[cpu].count);
                else
                        trace_seq_printf(trace->seq, "        - ");
        }
        trace_seq_printf(trace->seq, "\n");

        if (!params->common.hist.no_index)
                trace_seq_printf(trace->seq, "max:  ");

        for_each_monitored_cpu(cpu, data->nr_cpus, &params->common) {

                if (!data->hist[cpu].count)
                        continue;

                trace_seq_printf(trace->seq, "%9llu ", data->hist[cpu].max_sample);

        }
        trace_seq_printf(trace->seq, "\n");
        trace_seq_do_printf(trace->seq);
        trace_seq_reset(trace->seq);
}

/*
 * osnoise_print_stats - print data for all CPUs
 */
static void
osnoise_print_stats(struct osnoise_tool *tool)
{
        struct osnoise_params *params = to_osnoise_params(tool->params);
        struct osnoise_hist_data *data = tool->data;
        struct trace_instance *trace = &tool->trace;
        int has_samples = 0;
        int bucket, cpu;
        int total;

        osnoise_hist_header(tool);

        for (bucket = 0; bucket < data->entries; bucket++) {
                total = 0;

                if (!params->common.hist.no_index)
                        trace_seq_printf(trace->seq, "%-6d",
                                         bucket * data->bucket_size);

                for_each_monitored_cpu(cpu, data->nr_cpus, &params->common) {

                        if (!data->hist[cpu].count)
                                continue;

                        total += data->hist[cpu].samples[bucket];
                        trace_seq_printf(trace->seq, "%9d ", data->hist[cpu].samples[bucket]);
                }

                if (total == 0 && !params->common.hist.with_zeros) {
                        trace_seq_reset(trace->seq);
                        continue;
                }

                /* There are samples above the threshold */
                has_samples = 1;
                trace_seq_printf(trace->seq, "\n");
                trace_seq_do_printf(trace->seq);
                trace_seq_reset(trace->seq);
        }

        /*
         * If no samples were recorded, skip calculations, print zeroed statistics
         * and return.
         */
        if (!has_samples) {
                trace_seq_reset(trace->seq);
                trace_seq_printf(trace->seq, "over: 0\ncount: 0\nmin: 0\navg: 0\nmax: 0\n");
                trace_seq_do_printf(trace->seq);
                trace_seq_reset(trace->seq);
                return;
        }

        if (!params->common.hist.no_index)
                trace_seq_printf(trace->seq, "over: ");

        for_each_monitored_cpu(cpu, data->nr_cpus, &params->common) {

                if (!data->hist[cpu].count)
                        continue;

                trace_seq_printf(trace->seq, "%9d ",
                                 data->hist[cpu].samples[data->entries]);
        }
        trace_seq_printf(trace->seq, "\n");
        trace_seq_do_printf(trace->seq);
        trace_seq_reset(trace->seq);

        osnoise_print_summary(params, trace, data);
        osnoise_report_missed_events(tool);
}

/*
 * osnoise_hist_usage - prints osnoise hist usage message
 */
static void osnoise_hist_usage(void)
{
        static const char * const msg_start[] = {
                "[-D] [-d s] [-a us] [-p us] [-r us] [-s us] [-S us] \\",
                "         [-T us] [-t [file]] [-e sys[:event]] [--filter <filter>] [--trigger <trigger>] \\",
                "         [-c cpu-list] [-H cpu-list] [-P priority] [-b N] [-E N] [--no-header] [--no-summary] \\",
                "         [--no-index] [--with-zeros] [-C [cgroup_name]] [--warm-up]",
                NULL,
        };

        static const char * const msg_opts[] = {
                "         -a/--auto: set automatic trace mode, stopping the session if argument in us sample is hit",
                "         -p/--period us: osnoise period in us",
                "         -r/--runtime us: osnoise runtime in us",
                "         -s/--stop us: stop trace if a single sample is higher than the argument in us",
                "         -S/--stop-total us: stop trace if the total sample is higher than the argument in us",
                "         -T/--threshold us: the minimum delta to be considered a noise",
                "         -c/--cpus cpu-list: list of cpus to run osnoise threads",
                "         -H/--house-keeping cpus: run rtla control threads only on the given cpus",
                "         -C/--cgroup [cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited",
                "         -d/--duration time[s|m|h|d]: duration of the session",
                "         -D/--debug: print debug info",
                "         -t/--trace [file]: save the stopped trace to [file|osnoise_trace.txt]",
                "         -e/--event <sys:event>: enable the <sys:event> in the trace instance, multiple -e are allowed",
                "            --filter <filter>: enable a trace event filter to the previous -e event",
                "            --trigger <trigger>: enable a trace event trigger to the previous -e event",
                "         -b/--bucket-size N: set the histogram bucket size (default 1)",
                "         -E/--entries N: set the number of entries of the histogram (default 256)",
                "            --no-header: do not print header",
                "            --no-summary: do not print summary",
                "            --no-index: do not print index",
                "            --with-zeros: print zero only entries",
                "         -P/--priority o:prio|r:prio|f:prio|d:runtime:period: set scheduling parameters",
                "               o:prio - use SCHED_OTHER with prio",
                "               r:prio - use SCHED_RR with prio",
                "               f:prio - use SCHED_FIFO with prio",
                "               d:runtime[us|ms|s]:period[us|ms|s] - use SCHED_DEADLINE with runtime and period",
                "                                                      in nanoseconds",
                "            --warm-up: let the workload run for s seconds before collecting data",
                "            --trace-buffer-size kB: set the per-cpu trace buffer size in kB",
                "            --on-threshold <action>: define action to be executed at stop-total threshold, multiple are allowed",
                "            --on-end <action>: define action to be executed at measurement end, multiple are allowed",
                NULL,
        };

        common_usage("osnoise", "hist", "a per-cpu histogram of the OS noise",
                     msg_start, msg_opts);
}

/*
 * osnoise_hist_parse_args - allocs, parse and fill the cmd line parameters
 */
static struct common_params
*osnoise_hist_parse_args(int argc, char *argv[])
{
        struct osnoise_params *params;
        int retval;
        int c;
        char *trace_output = NULL;

        params = calloc(1, sizeof(*params));
        if (!params)
                exit(1);

        actions_init(&params->common.threshold_actions);
        actions_init(&params->common.end_actions);

        /* display data in microseconds */
        params->common.output_divisor = 1000;
        params->common.hist.bucket_size = 1;
        params->common.hist.entries = 256;

        while (1) {
                static struct option long_options[] = {
                        {"auto",                required_argument,      0, 'a'},
                        {"bucket-size",         required_argument,      0, 'b'},
                        {"entries",             required_argument,      0, 'E'},
                        {"help",                no_argument,            0, 'h'},
                        {"period",              required_argument,      0, 'p'},
                        {"runtime",             required_argument,      0, 'r'},
                        {"stop",                required_argument,      0, 's'},
                        {"stop-total",          required_argument,      0, 'S'},
                        {"trace",               optional_argument,      0, 't'},
                        {"threshold",           required_argument,      0, 'T'},
                        {"no-header",           no_argument,            0, '0'},
                        {"no-summary",          no_argument,            0, '1'},
                        {"no-index",            no_argument,            0, '2'},
                        {"with-zeros",          no_argument,            0, '3'},
                        {"trigger",             required_argument,      0, '4'},
                        {"filter",              required_argument,      0, '5'},
                        {"warm-up",             required_argument,      0, '6'},
                        {"trace-buffer-size",   required_argument,      0, '7'},
                        {"on-threshold",        required_argument,      0, '8'},
                        {"on-end",              required_argument,      0, '9'},
                        {0, 0, 0, 0}
                };

                if (common_parse_options(argc, argv, &params->common))
                        continue;

                c = getopt_long(argc, argv, "a:b:E:hp:r:s:S:t::T:01234:5:6:7:",
                                 long_options, NULL);

                /* detect the end of the options. */
                if (c == -1)
                        break;

                switch (c) {
                case 'a':
                        /* set sample stop to auto_thresh */
                        params->common.stop_us = get_llong_from_str(optarg);

                        /* set sample threshold to 1 */
                        params->threshold = 1;

                        /* set trace */
                        if (!trace_output)
                                trace_output = "osnoise_trace.txt";

                        break;
                case 'b':
                        params->common.hist.bucket_size = get_llong_from_str(optarg);
                        if (params->common.hist.bucket_size == 0 ||
                            params->common.hist.bucket_size >= 1000000)
                                fatal("Bucket size needs to be > 0 and <= 1000000");
                        break;
                case 'E':
                        params->common.hist.entries = get_llong_from_str(optarg);
                        if (params->common.hist.entries < 10 ||
                            params->common.hist.entries > 9999999)
                                fatal("Entries must be > 10 and < 9999999");
                        break;
                case 'h':
                case '?':
                        osnoise_hist_usage();
                        break;
                case 'p':
                        params->period = get_llong_from_str(optarg);
                        if (params->period > 10000000)
                                fatal("Period longer than 10 s");
                        break;
                case 'r':
                        params->runtime = get_llong_from_str(optarg);
                        if (params->runtime < 100)
                                fatal("Runtime shorter than 100 us");
                        break;
                case 's':
                        params->common.stop_us = get_llong_from_str(optarg);
                        break;
                case 'S':
                        params->common.stop_total_us = get_llong_from_str(optarg);
                        break;
                case 'T':
                        params->threshold = get_llong_from_str(optarg);
                        break;
                case 't':
                        trace_output = parse_optional_arg(argc, argv);
                        if (!trace_output)
                                trace_output = "osnoise_trace.txt";
                        break;
                case '0': /* no header */
                        params->common.hist.no_header = 1;
                        break;
                case '1': /* no summary */
                        params->common.hist.no_summary = 1;
                        break;
                case '2': /* no index */
                        params->common.hist.no_index = 1;
                        break;
                case '3': /* with zeros */
                        params->common.hist.with_zeros = 1;
                        break;
                case '4': /* trigger */
                        if (params->common.events) {
                                retval = trace_event_add_trigger(params->common.events, optarg);
                                if (retval)
                                        fatal("Error adding trigger %s", optarg);
                        } else {
                                fatal("--trigger requires a previous -e");
                        }
                        break;
                case '5': /* filter */
                        if (params->common.events) {
                                retval = trace_event_add_filter(params->common.events, optarg);
                                if (retval)
                                        fatal("Error adding filter %s", optarg);
                        } else {
                                fatal("--filter requires a previous -e");
                        }
                        break;
                case '6':
                        params->common.warmup = get_llong_from_str(optarg);
                        break;
                case '7':
                        params->common.buffer_size = get_llong_from_str(optarg);
                        break;
                case '8':
                        retval = actions_parse(&params->common.threshold_actions, optarg,
                                               "osnoise_trace.txt");
                        if (retval)
                                fatal("Invalid action %s", optarg);
                        break;
                case '9':
                        retval = actions_parse(&params->common.end_actions, optarg,
                                               "osnoise_trace.txt");
                        if (retval)
                                fatal("Invalid action %s", optarg);
                        break;
                default:
                        fatal("Invalid option");
                }
        }

        if (trace_output)
                actions_add_trace_output(&params->common.threshold_actions, trace_output);

        if (geteuid())
                fatal("rtla needs root permission");

        if (params->common.hist.no_index && !params->common.hist.with_zeros)
                fatal("no-index set and with-zeros not set - it does not make sense");

        return &params->common;
}

/*
 * osnoise_hist_apply_config - apply the hist configs to the initialized tool
 */
static int
osnoise_hist_apply_config(struct osnoise_tool *tool)
{
        return osnoise_apply_config(tool, to_osnoise_params(tool->params));
}

/*
 * osnoise_init_hist - initialize a osnoise hist tool with parameters
 */
static struct osnoise_tool
*osnoise_init_hist(struct common_params *params)
{
        struct osnoise_tool *tool;
        int nr_cpus;

        nr_cpus = sysconf(_SC_NPROCESSORS_CONF);

        tool = osnoise_init_tool("osnoise_hist");
        if (!tool)
                return NULL;

        tool->data = osnoise_alloc_histogram(nr_cpus, params->hist.entries,
                                             params->hist.bucket_size);
        if (!tool->data)
                goto out_err;

        return tool;

out_err:
        osnoise_destroy_tool(tool);
        return NULL;
}

static int osnoise_hist_enable(struct osnoise_tool *tool)
{
        int retval;

        retval = osnoise_init_trace_hist(tool);
        if (retval)
                return retval;

        return osnoise_enable(tool);
}

static int osnoise_hist_main_loop(struct osnoise_tool *tool)
{
        int retval;

        retval = hist_main_loop(tool);
        osnoise_read_trace_hist(tool);

        return retval;
}

struct tool_ops osnoise_hist_ops = {
        .tracer = "osnoise",
        .comm_prefix = "osnoise/",
        .parse_args = osnoise_hist_parse_args,
        .init_tool = osnoise_init_hist,
        .apply_config = osnoise_hist_apply_config,
        .enable = osnoise_hist_enable,
        .main = osnoise_hist_main_loop,
        .print_stats = osnoise_print_stats,
        .free = osnoise_free_hist_tool,
};