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

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

#include "osnoise.h"
#include "cli.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;
};

/*
 * 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 < 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 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->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, &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, &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, &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, &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, &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, &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, &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_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;

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

        tool->data = osnoise_alloc_histogram(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,
};