// 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 <sched.h>
#include <pthread.h>

#include "timerlat.h"
#include "timerlat_aa.h"
#include "timerlat_bpf.h"
#include "cli.h"
#include "common.h"

struct timerlat_hist_cpu {
        int                     *irq;
        int                     *thread;
        int                     *user;

        unsigned long long      irq_count;
        unsigned long long      thread_count;
        unsigned long long      user_count;

        unsigned long long      min_irq;
        unsigned long long      sum_irq;
        unsigned long long      max_irq;

        unsigned long long      min_thread;
        unsigned long long      sum_thread;
        unsigned long long      max_thread;

        unsigned long long      min_user;
        unsigned long long      sum_user;
        unsigned long long      max_user;
};

struct timerlat_hist_data {
        struct timerlat_hist_cpu        *hist;
        int                             entries;
        int                             bucket_size;
};

/*
 * timerlat_free_histogram - free runtime data
 */
static void
timerlat_free_histogram(struct timerlat_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].irq)
                        free(data->hist[cpu].irq);

                if (data->hist[cpu].thread)
                        free(data->hist[cpu].thread);

                if (data->hist[cpu].user)
                        free(data->hist[cpu].user);

        }

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

static void timerlat_free_histogram_tool(struct osnoise_tool *tool)
{
        timerlat_free_histogram(tool->data);
        timerlat_free(tool);
}

/*
 * timerlat_alloc_histogram - alloc runtime data
 */
static struct timerlat_hist_data
*timerlat_alloc_histogram(int entries, int bucket_size)
{
        struct timerlat_hist_data *data;
        int cpu;

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

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

        /* one set of histograms per CPU */
        data->hist = calloc(1, sizeof(*data->hist) * nr_cpus);
        if (!data->hist)
                goto cleanup;

        /* one histogram for IRQ and one for thread, per cpu */
        for (cpu = 0; cpu < nr_cpus; cpu++) {
                data->hist[cpu].irq = calloc(1, sizeof(*data->hist->irq) * (entries + 1));
                if (!data->hist[cpu].irq)
                        goto cleanup;

                data->hist[cpu].thread = calloc(1, sizeof(*data->hist->thread) * (entries + 1));
                if (!data->hist[cpu].thread)
                        goto cleanup;

                data->hist[cpu].user = calloc(1, sizeof(*data->hist->user) * (entries + 1));
                if (!data->hist[cpu].user)
                        goto cleanup;
        }

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

        return data;

cleanup:
        timerlat_free_histogram(data);
        return NULL;
}

/*
 * timerlat_hist_update - record a new timerlat occurent on cpu, updating data
 */
static void
timerlat_hist_update(struct osnoise_tool *tool, int cpu,
                     unsigned long long context,
                     unsigned long long latency)
{
        struct timerlat_params *params = to_timerlat_params(tool->params);
        struct timerlat_hist_data *data = tool->data;
        int entries = data->entries;
        int bucket;
        int *hist;

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

        bucket = latency / data->bucket_size;

        if (!context) {
                hist = data->hist[cpu].irq;
                data->hist[cpu].irq_count++;
                update_min(&data->hist[cpu].min_irq, &latency);
                update_sum(&data->hist[cpu].sum_irq, &latency);
                update_max(&data->hist[cpu].max_irq, &latency);
        } else if (context == 1) {
                hist = data->hist[cpu].thread;
                data->hist[cpu].thread_count++;
                update_min(&data->hist[cpu].min_thread, &latency);
                update_sum(&data->hist[cpu].sum_thread, &latency);
                update_max(&data->hist[cpu].max_thread, &latency);
        } else { /* user */
                hist = data->hist[cpu].user;
                data->hist[cpu].user_count++;
                update_min(&data->hist[cpu].min_user, &latency);
                update_sum(&data->hist[cpu].sum_user, &latency);
                update_max(&data->hist[cpu].max_user, &latency);
        }

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

/*
 * timerlat_hist_handler - this is the handler for timerlat tracer events
 */
static int
timerlat_hist_handler(struct trace_seq *s, struct tep_record *record,
                     struct tep_event *event, void *data)
{
        struct trace_instance *trace = data;
        unsigned long long context, latency;
        struct osnoise_tool *tool;
        int cpu = record->cpu;

        tool = container_of(trace, struct osnoise_tool, trace);

        tep_get_field_val(s, event, "context", record, &context, 1);
        tep_get_field_val(s, event, "timer_latency", record, &latency, 1);

        timerlat_hist_update(tool, cpu, context, latency);

        return 0;
}

/*
 * timerlat_hist_bpf_pull_data - copy data from BPF maps into userspace
 */
static int timerlat_hist_bpf_pull_data(struct osnoise_tool *tool)
{
        struct timerlat_hist_data *data = tool->data;
        int i, j, err;
        long long value_irq[nr_cpus],
                  value_thread[nr_cpus],
                  value_user[nr_cpus];

        /* Pull histogram */
        for (i = 0; i < data->entries; i++) {
                err = timerlat_bpf_get_hist_value(i, value_irq, value_thread,
                                                  value_user);
                if (err)
                        return err;
                for (j = 0; j < nr_cpus; j++) {
                        data->hist[j].irq[i] = value_irq[j];
                        data->hist[j].thread[i] = value_thread[j];
                        data->hist[j].user[i] = value_user[j];
                }
        }

        /* Pull summary */
        err = timerlat_bpf_get_summary_value(SUMMARY_COUNT,
                                             value_irq, value_thread, value_user);
        if (err)
                return err;
        for (i = 0; i < nr_cpus; i++) {
                data->hist[i].irq_count = value_irq[i];
                data->hist[i].thread_count = value_thread[i];
                data->hist[i].user_count = value_user[i];
        }

        err = timerlat_bpf_get_summary_value(SUMMARY_MIN,
                                             value_irq, value_thread, value_user);
        if (err)
                return err;
        for (i = 0; i < nr_cpus; i++) {
                data->hist[i].min_irq = value_irq[i];
                data->hist[i].min_thread = value_thread[i];
                data->hist[i].min_user = value_user[i];
        }

        err = timerlat_bpf_get_summary_value(SUMMARY_MAX,
                                             value_irq, value_thread, value_user);
        if (err)
                return err;
        for (i = 0; i < nr_cpus; i++) {
                data->hist[i].max_irq = value_irq[i];
                data->hist[i].max_thread = value_thread[i];
                data->hist[i].max_user = value_user[i];
        }

        err = timerlat_bpf_get_summary_value(SUMMARY_SUM,
                                             value_irq, value_thread, value_user);
        if (err)
                return err;
        for (i = 0; i < nr_cpus; i++) {
                data->hist[i].sum_irq = value_irq[i];
                data->hist[i].sum_thread = value_thread[i];
                data->hist[i].sum_user = value_user[i];
        }

        err = timerlat_bpf_get_summary_value(SUMMARY_OVERFLOW,
                                             value_irq, value_thread, value_user);
        if (err)
                return err;
        for (i = 0; i < nr_cpus; i++) {
                data->hist[i].irq[data->entries] = value_irq[i];
                data->hist[i].thread[data->entries] = value_thread[i];
                data->hist[i].user[data->entries] = value_user[i];
        }

        return 0;
}

/*
 * timerlat_hist_header - print the header of the tracer to the output
 */
static void timerlat_hist_header(struct osnoise_tool *tool)
{
        struct timerlat_params *params = to_timerlat_params(tool->params);
        struct timerlat_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 timerlat 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].irq_count && !data->hist[cpu].thread_count)
                        continue;

                if (!params->common.hist.no_irq)
                        trace_seq_printf(s, "   IRQ-%03d", cpu);

                if (!params->common.hist.no_thread)
                        trace_seq_printf(s, "   Thr-%03d", cpu);

                if (params->common.user_data)
                        trace_seq_printf(s, "   Usr-%03d", cpu);
        }
        trace_seq_printf(s, "\n");


        trace_seq_do_printf(s);
        trace_seq_reset(s);
}

/*
 * format_summary_value - format a line of summary value (min, max or avg)
 * of hist data
 */
static void format_summary_value(struct trace_seq *seq,
                                 int count,
                                 unsigned long long val,
                                 bool avg)
{
        if (count)
                trace_seq_printf(seq, "%9llu ", avg ? val / count : val);
        else
                trace_seq_printf(seq, "%9c ", '-');
}

/*
 * timerlat_print_summary - print the summary of the hist data to the output
 */
static void
timerlat_print_summary(struct timerlat_params *params,
                       struct trace_instance *trace,
                       struct timerlat_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].irq_count && !data->hist[cpu].thread_count)
                        continue;

                if (!params->common.hist.no_irq)
                        trace_seq_printf(trace->seq, "%9llu ",
                                        data->hist[cpu].irq_count);

                if (!params->common.hist.no_thread)
                        trace_seq_printf(trace->seq, "%9llu ",
                                        data->hist[cpu].thread_count);

                if (params->common.user_data)
                        trace_seq_printf(trace->seq, "%9llu ",
                                         data->hist[cpu].user_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].irq_count && !data->hist[cpu].thread_count)
                        continue;

                if (!params->common.hist.no_irq)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].irq_count,
                                             data->hist[cpu].min_irq,
                                             false);

                if (!params->common.hist.no_thread)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].thread_count,
                                             data->hist[cpu].min_thread,
                                             false);

                if (params->common.user_data)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].user_count,
                                             data->hist[cpu].min_user,
                                             false);
        }
        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].irq_count && !data->hist[cpu].thread_count)
                        continue;

                if (!params->common.hist.no_irq)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].irq_count,
                                             data->hist[cpu].sum_irq,
                                             true);

                if (!params->common.hist.no_thread)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].thread_count,
                                             data->hist[cpu].sum_thread,
                                             true);

                if (params->common.user_data)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].user_count,
                                             data->hist[cpu].sum_user,
                                             true);
        }
        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].irq_count && !data->hist[cpu].thread_count)
                        continue;

                if (!params->common.hist.no_irq)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].irq_count,
                                             data->hist[cpu].max_irq,
                                             false);

                if (!params->common.hist.no_thread)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].thread_count,
                                             data->hist[cpu].max_thread,
                                             false);

                if (params->common.user_data)
                        format_summary_value(trace->seq,
                                             data->hist[cpu].user_count,
                                             data->hist[cpu].max_user,
                                             false);
        }
        trace_seq_printf(trace->seq, "\n");
        trace_seq_do_printf(trace->seq);
        trace_seq_reset(trace->seq);
}

static void
timerlat_print_stats_all(struct timerlat_params *params,
                         struct trace_instance *trace,
                         struct timerlat_hist_data *data)
{
        struct timerlat_hist_cpu *cpu_data;
        struct timerlat_hist_cpu sum;
        int cpu;

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

        memset(&sum, 0, sizeof(sum));
        sum.min_irq = ~0;
        sum.min_thread = ~0;
        sum.min_user = ~0;

        for_each_monitored_cpu(cpu, &params->common) {

                if (!data->hist[cpu].irq_count && !data->hist[cpu].thread_count)
                        continue;

                cpu_data = &data->hist[cpu];

                sum.irq_count += cpu_data->irq_count;
                update_min(&sum.min_irq, &cpu_data->min_irq);
                update_sum(&sum.sum_irq, &cpu_data->sum_irq);
                update_max(&sum.max_irq, &cpu_data->max_irq);

                sum.thread_count += cpu_data->thread_count;
                update_min(&sum.min_thread, &cpu_data->min_thread);
                update_sum(&sum.sum_thread, &cpu_data->sum_thread);
                update_max(&sum.max_thread, &cpu_data->max_thread);

                sum.user_count += cpu_data->user_count;
                update_min(&sum.min_user, &cpu_data->min_user);
                update_sum(&sum.sum_user, &cpu_data->sum_user);
                update_max(&sum.max_user, &cpu_data->max_user);
        }

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

        if (!params->common.hist.no_irq)
                trace_seq_printf(trace->seq, "      IRQ");

        if (!params->common.hist.no_thread)
                trace_seq_printf(trace->seq, "       Thr");

        if (params->common.user_data)
                trace_seq_printf(trace->seq, "       Usr");

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

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

        if (!params->common.hist.no_irq)
                trace_seq_printf(trace->seq, "%9llu ",
                                 sum.irq_count);

        if (!params->common.hist.no_thread)
                trace_seq_printf(trace->seq, "%9llu ",
                                 sum.thread_count);

        if (params->common.user_data)
                trace_seq_printf(trace->seq, "%9llu ",
                                 sum.user_count);

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

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

        if (!params->common.hist.no_irq)
                format_summary_value(trace->seq,
                                     sum.irq_count,
                                     sum.min_irq,
                                     false);

        if (!params->common.hist.no_thread)
                format_summary_value(trace->seq,
                                     sum.thread_count,
                                     sum.min_thread,
                                     false);

        if (params->common.user_data)
                format_summary_value(trace->seq,
                                     sum.user_count,
                                     sum.min_user,
                                     false);

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

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

        if (!params->common.hist.no_irq)
                format_summary_value(trace->seq,
                                     sum.irq_count,
                                     sum.sum_irq,
                                     true);

        if (!params->common.hist.no_thread)
                format_summary_value(trace->seq,
                                     sum.thread_count,
                                     sum.sum_thread,
                                     true);

        if (params->common.user_data)
                format_summary_value(trace->seq,
                                     sum.user_count,
                                     sum.sum_user,
                                     true);

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

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

        if (!params->common.hist.no_irq)
                format_summary_value(trace->seq,
                                     sum.irq_count,
                                     sum.max_irq,
                                     false);

        if (!params->common.hist.no_thread)
                format_summary_value(trace->seq,
                                     sum.thread_count,
                                     sum.max_thread,
                                     false);

        if (params->common.user_data)
                format_summary_value(trace->seq,
                                     sum.user_count,
                                     sum.max_user,
                                     false);

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

/*
 * timerlat_print_stats - print data for each CPUs
 */
static void
timerlat_print_stats(struct osnoise_tool *tool)
{
        struct timerlat_params *params = to_timerlat_params(tool->params);
        struct timerlat_hist_data *data = tool->data;
        struct trace_instance *trace = &tool->trace;
        int bucket, cpu;
        int total;

        timerlat_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].irq_count && !data->hist[cpu].thread_count)
                                continue;

                        if (!params->common.hist.no_irq) {
                                total += data->hist[cpu].irq[bucket];
                                trace_seq_printf(trace->seq, "%9d ",
                                                data->hist[cpu].irq[bucket]);
                        }

                        if (!params->common.hist.no_thread) {
                                total += data->hist[cpu].thread[bucket];
                                trace_seq_printf(trace->seq, "%9d ",
                                                data->hist[cpu].thread[bucket]);
                        }

                        if (params->common.user_data) {
                                total += data->hist[cpu].user[bucket];
                                trace_seq_printf(trace->seq, "%9d ",
                                                data->hist[cpu].user[bucket]);
                        }

                }

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

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

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

        for_each_monitored_cpu(cpu, &params->common) {

                if (!data->hist[cpu].irq_count && !data->hist[cpu].thread_count)
                        continue;

                if (!params->common.hist.no_irq)
                        trace_seq_printf(trace->seq, "%9d ",
                                         data->hist[cpu].irq[data->entries]);

                if (!params->common.hist.no_thread)
                        trace_seq_printf(trace->seq, "%9d ",
                                         data->hist[cpu].thread[data->entries]);

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

        timerlat_print_summary(params, trace, data);
        timerlat_print_stats_all(params, trace, data);
        osnoise_report_missed_events(tool);
}

/*
 * timerlat_hist_apply_config - apply the hist configs to the initialized tool
 */
static int
timerlat_hist_apply_config(struct osnoise_tool *tool)
{
        struct timerlat_params *params = to_timerlat_params(tool->params);
        int retval;

        retval = timerlat_apply_config(tool, params);
        if (retval)
                goto out_err;

        return 0;

out_err:
        return -1;
}

/*
 * timerlat_init_hist - initialize a timerlat hist tool with parameters
 */
static struct osnoise_tool
*timerlat_init_hist(struct common_params *params)
{
        struct osnoise_tool *tool;

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

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

        tep_register_event_handler(tool->trace.tep, -1, "ftrace", "timerlat",
                                   timerlat_hist_handler, tool);

        return tool;

out_err:
        osnoise_destroy_tool(tool);
        return NULL;
}

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

        while (!stop_tracing) {
                timerlat_bpf_wait(-1);

                if (!stop_tracing) {
                        /* Threshold overflow, perform actions on threshold */
                        retval = common_threshold_handler(tool);
                        if (retval)
                                return retval;

                        if (!should_continue_tracing(tool->params))
                                break;

                        if (timerlat_bpf_restart_tracing()) {
                                err_msg("Error restarting BPF trace\n");
                                return -1;
                        }
                }
        }
        timerlat_bpf_detach();

        retval = timerlat_hist_bpf_pull_data(tool);
        if (retval)
                err_msg("Error pulling BPF data\n");

        return retval;
}

static int timerlat_hist_main(struct osnoise_tool *tool)
{
        struct timerlat_params *params = to_timerlat_params(tool->params);
        int retval;

        if (params->mode == TRACING_MODE_TRACEFS)
                retval = hist_main_loop(tool);
        else
                retval = timerlat_hist_bpf_main_loop(tool);

        return retval;
}

struct tool_ops timerlat_hist_ops = {
        .tracer = "timerlat",
        .comm_prefix = "timerlat/",
        .parse_args = timerlat_hist_parse_args,
        .init_tool = timerlat_init_hist,
        .apply_config = timerlat_hist_apply_config,
        .enable = timerlat_enable,
        .main = timerlat_hist_main,
        .print_stats = timerlat_print_stats,
        .analyze = timerlat_analyze,
        .free = timerlat_free_histogram_tool,
};