// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <asm/barrier.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include <sys/epoll.h>
#include <sys/mman.h>
#include <argp.h>
#include <stdlib.h>
#include "bench.h"
#include "ringbuf_bench.skel.h"
#include "perfbuf_bench.skel.h"

static struct {
        bool back2back;
        int batch_cnt;
        bool sampled;
        int sample_rate;
        int ringbuf_sz; /* per-ringbuf, in bytes */
        bool ringbuf_use_output; /* use slower output API */
        int perfbuf_sz; /* per-CPU size, in pages */
} args = {
        .back2back = false,
        .batch_cnt = 500,
        .sampled = false,
        .sample_rate = 500,
        .ringbuf_sz = 512 * 1024,
        .ringbuf_use_output = false,
        .perfbuf_sz = 128,
};

enum {
        ARG_RB_BACK2BACK = 2000,
        ARG_RB_USE_OUTPUT = 2001,
        ARG_RB_BATCH_CNT = 2002,
        ARG_RB_SAMPLED = 2003,
        ARG_RB_SAMPLE_RATE = 2004,
};

static const struct argp_option opts[] = {
        { "rb-b2b", ARG_RB_BACK2BACK, NULL, 0, "Back-to-back mode"},
        { "rb-use-output", ARG_RB_USE_OUTPUT, NULL, 0, "Use bpf_ringbuf_output() instead of bpf_ringbuf_reserve()"},
        { "rb-batch-cnt", ARG_RB_BATCH_CNT, "CNT", 0, "Set BPF-side record batch count"},
        { "rb-sampled", ARG_RB_SAMPLED, NULL, 0, "Notification sampling"},
        { "rb-sample-rate", ARG_RB_SAMPLE_RATE, "RATE", 0, "Notification sample rate"},
        {},
};

static error_t parse_arg(int key, char *arg, struct argp_state *state)
{
        switch (key) {
        case ARG_RB_BACK2BACK:
                args.back2back = true;
                break;
        case ARG_RB_USE_OUTPUT:
                args.ringbuf_use_output = true;
                break;
        case ARG_RB_BATCH_CNT:
                args.batch_cnt = strtol(arg, NULL, 10);
                if (args.batch_cnt < 0) {
                        fprintf(stderr, "Invalid batch count.");
                        argp_usage(state);
                }
                break;
        case ARG_RB_SAMPLED:
                args.sampled = true;
                break;
        case ARG_RB_SAMPLE_RATE:
                args.sample_rate = strtol(arg, NULL, 10);
                if (args.sample_rate < 0) {
                        fprintf(stderr, "Invalid perfbuf sample rate.");
                        argp_usage(state);
                }
                break;
        default:
                return ARGP_ERR_UNKNOWN;
        }
        return 0;
}

/* exported into benchmark runner */
const struct argp bench_ringbufs_argp = {
        .options = opts,
        .parser = parse_arg,
};

/* RINGBUF-LIBBPF benchmark */

static struct counter buf_hits;

static inline void bufs_trigger_batch()
{
        (void)syscall(__NR_getpgid);
}

static void bufs_validate()
{
        if (env.consumer_cnt != 1) {
                fprintf(stderr, "rb-libbpf benchmark doesn't support multi-consumer!\n");
                exit(1);
        }

        if (args.back2back && env.producer_cnt > 1) {
                fprintf(stderr, "back-to-back mode makes sense only for single-producer case!\n");
                exit(1);
        }
}

static void *bufs_sample_producer(void *input)
{
        if (args.back2back) {
                /* initial batch to get everything started */
                bufs_trigger_batch();
                return NULL;
        }

        while (true)
                bufs_trigger_batch();
        return NULL;
}

static struct ringbuf_libbpf_ctx {
        struct ringbuf_bench *skel;
        struct ring_buffer *ringbuf;
} ringbuf_libbpf_ctx;

static void ringbuf_libbpf_measure(struct bench_res *res)
{
        struct ringbuf_libbpf_ctx *ctx = &ringbuf_libbpf_ctx;

        res->hits = atomic_swap(&buf_hits.value, 0);
        res->drops = atomic_swap(&ctx->skel->bss->dropped, 0);
}

static struct ringbuf_bench *ringbuf_setup_skeleton()
{
        struct ringbuf_bench *skel;

        setup_libbpf();

        skel = ringbuf_bench__open();
        if (!skel) {
                fprintf(stderr, "failed to open skeleton\n");
                exit(1);
        }

        skel->rodata->batch_cnt = args.batch_cnt;
        skel->rodata->use_output = args.ringbuf_use_output ? 1 : 0;

        if (args.sampled)
                /* record data + header take 16 bytes */
                skel->rodata->wakeup_data_size = args.sample_rate * 16;

        bpf_map__resize(skel->maps.ringbuf, args.ringbuf_sz);

        if (ringbuf_bench__load(skel)) {
                fprintf(stderr, "failed to load skeleton\n");
                exit(1);
        }

        return skel;
}

static int buf_process_sample(void *ctx, void *data, size_t len)
{
        atomic_inc(&buf_hits.value);
        return 0;
}

static void ringbuf_libbpf_setup()
{
        struct ringbuf_libbpf_ctx *ctx = &ringbuf_libbpf_ctx;
        struct bpf_link *link;

        ctx->skel = ringbuf_setup_skeleton();
        ctx->ringbuf = ring_buffer__new(bpf_map__fd(ctx->skel->maps.ringbuf),
                                        buf_process_sample, NULL, NULL);
        if (!ctx->ringbuf) {
                fprintf(stderr, "failed to create ringbuf\n");
                exit(1);
        }

        link = bpf_program__attach(ctx->skel->progs.bench_ringbuf);
        if (!link) {
                fprintf(stderr, "failed to attach program!\n");
                exit(1);
        }
}

static void *ringbuf_libbpf_consumer(void *input)
{
        struct ringbuf_libbpf_ctx *ctx = &ringbuf_libbpf_ctx;

        while (ring_buffer__poll(ctx->ringbuf, -1) >= 0) {
                if (args.back2back)
                        bufs_trigger_batch();
        }
        fprintf(stderr, "ringbuf polling failed!\n");
        return NULL;
}

/* RINGBUF-CUSTOM benchmark */
struct ringbuf_custom {
        __u64 *consumer_pos;
        __u64 *producer_pos;
        __u64 mask;
        void *data;
        int map_fd;
};

static struct ringbuf_custom_ctx {
        struct ringbuf_bench *skel;
        struct ringbuf_custom ringbuf;
        int epoll_fd;
        struct epoll_event event;
} ringbuf_custom_ctx;

static void ringbuf_custom_measure(struct bench_res *res)
{
        struct ringbuf_custom_ctx *ctx = &ringbuf_custom_ctx;

        res->hits = atomic_swap(&buf_hits.value, 0);
        res->drops = atomic_swap(&ctx->skel->bss->dropped, 0);
}

static void ringbuf_custom_setup()
{
        struct ringbuf_custom_ctx *ctx = &ringbuf_custom_ctx;
        const size_t page_size = getpagesize();
        struct bpf_link *link;
        struct ringbuf_custom *r;
        void *tmp;
        int err;

        ctx->skel = ringbuf_setup_skeleton();

        ctx->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
        if (ctx->epoll_fd < 0) {
                fprintf(stderr, "failed to create epoll fd: %d\n", -errno);
                exit(1);
        }

        r = &ctx->ringbuf;
        r->map_fd = bpf_map__fd(ctx->skel->maps.ringbuf);
        r->mask = args.ringbuf_sz - 1;

        /* Map writable consumer page */
        tmp = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED,
                   r->map_fd, 0);
        if (tmp == MAP_FAILED) {
                fprintf(stderr, "failed to mmap consumer page: %d\n", -errno);
                exit(1);
        }
        r->consumer_pos = tmp;

        /* Map read-only producer page and data pages. */
        tmp = mmap(NULL, page_size + 2 * args.ringbuf_sz, PROT_READ, MAP_SHARED,
                   r->map_fd, page_size);
        if (tmp == MAP_FAILED) {
                fprintf(stderr, "failed to mmap data pages: %d\n", -errno);
                exit(1);
        }
        r->producer_pos = tmp;
        r->data = tmp + page_size;

        ctx->event.events = EPOLLIN;
        err = epoll_ctl(ctx->epoll_fd, EPOLL_CTL_ADD, r->map_fd, &ctx->event);
        if (err < 0) {
                fprintf(stderr, "failed to epoll add ringbuf: %d\n", -errno);
                exit(1);
        }

        link = bpf_program__attach(ctx->skel->progs.bench_ringbuf);
        if (!link) {
                fprintf(stderr, "failed to attach program\n");
                exit(1);
        }
}

#define RINGBUF_BUSY_BIT (1 << 31)
#define RINGBUF_DISCARD_BIT (1 << 30)
#define RINGBUF_META_LEN 8

static inline int roundup_len(__u32 len)
{
        /* clear out top 2 bits */
        len <<= 2;
        len >>= 2;
        /* add length prefix */
        len += RINGBUF_META_LEN;
        /* round up to 8 byte alignment */
        return (len + 7) / 8 * 8;
}

static void ringbuf_custom_process_ring(struct ringbuf_custom *r)
{
        unsigned long cons_pos, prod_pos;
        int *len_ptr, len;
        bool got_new_data;

        cons_pos = smp_load_acquire(r->consumer_pos);
        while (true) {
                got_new_data = false;
                prod_pos = smp_load_acquire(r->producer_pos);
                while (cons_pos < prod_pos) {
                        len_ptr = r->data + (cons_pos & r->mask);
                        len = smp_load_acquire(len_ptr);

                        /* sample not committed yet, bail out for now */
                        if (len & RINGBUF_BUSY_BIT)
                                return;

                        got_new_data = true;
                        cons_pos += roundup_len(len);

                        atomic_inc(&buf_hits.value);
                }
                if (got_new_data)
                        smp_store_release(r->consumer_pos, cons_pos);
                else
                        break;
        }
}

static void *ringbuf_custom_consumer(void *input)
{
        struct ringbuf_custom_ctx *ctx = &ringbuf_custom_ctx;
        int cnt;

        do {
                if (args.back2back)
                        bufs_trigger_batch();
                cnt = epoll_wait(ctx->epoll_fd, &ctx->event, 1, -1);
                if (cnt > 0)
                        ringbuf_custom_process_ring(&ctx->ringbuf);
        } while (cnt >= 0);
        fprintf(stderr, "ringbuf polling failed!\n");
        return 0;
}

/* PERFBUF-LIBBPF benchmark */
static struct perfbuf_libbpf_ctx {
        struct perfbuf_bench *skel;
        struct perf_buffer *perfbuf;
} perfbuf_libbpf_ctx;

static void perfbuf_measure(struct bench_res *res)
{
        struct perfbuf_libbpf_ctx *ctx = &perfbuf_libbpf_ctx;

        res->hits = atomic_swap(&buf_hits.value, 0);
        res->drops = atomic_swap(&ctx->skel->bss->dropped, 0);
}

static struct perfbuf_bench *perfbuf_setup_skeleton()
{
        struct perfbuf_bench *skel;

        setup_libbpf();

        skel = perfbuf_bench__open();
        if (!skel) {
                fprintf(stderr, "failed to open skeleton\n");
                exit(1);
        }

        skel->rodata->batch_cnt = args.batch_cnt;

        if (perfbuf_bench__load(skel)) {
                fprintf(stderr, "failed to load skeleton\n");
                exit(1);
        }

        return skel;
}

static enum bpf_perf_event_ret
perfbuf_process_sample_raw(void *input_ctx, int cpu,
                           struct perf_event_header *e)
{
        switch (e->type) {
        case PERF_RECORD_SAMPLE:
                atomic_inc(&buf_hits.value);
                break;
        case PERF_RECORD_LOST:
                break;
        default:
                return LIBBPF_PERF_EVENT_ERROR;
        }
        return LIBBPF_PERF_EVENT_CONT;
}

static void perfbuf_libbpf_setup()
{
        struct perfbuf_libbpf_ctx *ctx = &perfbuf_libbpf_ctx;
        struct perf_event_attr attr;
        struct perf_buffer_raw_opts pb_opts = {
                .event_cb = perfbuf_process_sample_raw,
                .ctx = (void *)(long)0,
                .attr = &attr,
        };
        struct bpf_link *link;

        ctx->skel = perfbuf_setup_skeleton();

        memset(&attr, 0, sizeof(attr));
        attr.config = PERF_COUNT_SW_BPF_OUTPUT,
        attr.type = PERF_TYPE_SOFTWARE;
        attr.sample_type = PERF_SAMPLE_RAW;
        /* notify only every Nth sample */
        if (args.sampled) {
                attr.sample_period = args.sample_rate;
                attr.wakeup_events = args.sample_rate;
        } else {
                attr.sample_period = 1;
                attr.wakeup_events = 1;
        }

        if (args.sample_rate > args.batch_cnt) {
                fprintf(stderr, "sample rate %d is too high for given batch count %d\n",
                        args.sample_rate, args.batch_cnt);
                exit(1);
        }

        ctx->perfbuf = perf_buffer__new_raw(bpf_map__fd(ctx->skel->maps.perfbuf),
                                            args.perfbuf_sz, &pb_opts);
        if (!ctx->perfbuf) {
                fprintf(stderr, "failed to create perfbuf\n");
                exit(1);
        }

        link = bpf_program__attach(ctx->skel->progs.bench_perfbuf);
        if (!link) {
                fprintf(stderr, "failed to attach program\n");
                exit(1);
        }
}

static void *perfbuf_libbpf_consumer(void *input)
{
        struct perfbuf_libbpf_ctx *ctx = &perfbuf_libbpf_ctx;

        while (perf_buffer__poll(ctx->perfbuf, -1) >= 0) {
                if (args.back2back)
                        bufs_trigger_batch();
        }
        fprintf(stderr, "perfbuf polling failed!\n");
        return NULL;
}

/* PERFBUF-CUSTOM benchmark */

/* copies of internal libbpf definitions */
struct perf_cpu_buf {
        struct perf_buffer *pb;
        void *base; /* mmap()'ed memory */
        void *buf; /* for reconstructing segmented data */
        size_t buf_size;
        int fd;
        int cpu;
        int map_key;
};

struct perf_buffer {
        perf_buffer_event_fn event_cb;
        perf_buffer_sample_fn sample_cb;
        perf_buffer_lost_fn lost_cb;
        void *ctx; /* passed into callbacks */

        size_t page_size;
        size_t mmap_size;
        struct perf_cpu_buf **cpu_bufs;
        struct epoll_event *events;
        int cpu_cnt; /* number of allocated CPU buffers */
        int epoll_fd; /* perf event FD */
        int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
};

static void *perfbuf_custom_consumer(void *input)
{
        struct perfbuf_libbpf_ctx *ctx = &perfbuf_libbpf_ctx;
        struct perf_buffer *pb = ctx->perfbuf;
        struct perf_cpu_buf *cpu_buf;
        struct perf_event_mmap_page *header;
        size_t mmap_mask = pb->mmap_size - 1;
        struct perf_event_header *ehdr;
        __u64 data_head, data_tail;
        size_t ehdr_size;
        void *base;
        int i, cnt;

        while (true) {
                if (args.back2back)
                        bufs_trigger_batch();
                cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, -1);
                if (cnt <= 0) {
                        fprintf(stderr, "perf epoll failed: %d\n", -errno);
                        exit(1);
                }

                for (i = 0; i < cnt; ++i) {
                        cpu_buf = pb->events[i].data.ptr;
                        header = cpu_buf->base;
                        base = ((void *)header) + pb->page_size;

                        data_head = ring_buffer_read_head(header);
                        data_tail = header->data_tail;
                        while (data_head != data_tail) {
                                ehdr = base + (data_tail & mmap_mask);
                                ehdr_size = ehdr->size;

                                if (ehdr->type == PERF_RECORD_SAMPLE)
                                        atomic_inc(&buf_hits.value);

                                data_tail += ehdr_size;
                        }
                        ring_buffer_write_tail(header, data_tail);
                }
        }
        return NULL;
}

const struct bench bench_rb_libbpf = {
        .name = "rb-libbpf",
        .validate = bufs_validate,
        .setup = ringbuf_libbpf_setup,
        .producer_thread = bufs_sample_producer,
        .consumer_thread = ringbuf_libbpf_consumer,
        .measure = ringbuf_libbpf_measure,
        .report_progress = hits_drops_report_progress,
        .report_final = hits_drops_report_final,
};

const struct bench bench_rb_custom = {
        .name = "rb-custom",
        .validate = bufs_validate,
        .setup = ringbuf_custom_setup,
        .producer_thread = bufs_sample_producer,
        .consumer_thread = ringbuf_custom_consumer,
        .measure = ringbuf_custom_measure,
        .report_progress = hits_drops_report_progress,
        .report_final = hits_drops_report_final,
};

const struct bench bench_pb_libbpf = {
        .name = "pb-libbpf",
        .validate = bufs_validate,
        .setup = perfbuf_libbpf_setup,
        .producer_thread = bufs_sample_producer,
        .consumer_thread = perfbuf_libbpf_consumer,
        .measure = perfbuf_measure,
        .report_progress = hits_drops_report_progress,
        .report_final = hits_drops_report_final,
};

const struct bench bench_pb_custom = {
        .name = "pb-custom",
        .validate = bufs_validate,
        .setup = perfbuf_libbpf_setup,
        .producer_thread = bufs_sample_producer,
        .consumer_thread = perfbuf_custom_consumer,
        .measure = perfbuf_measure,
        .report_progress = hits_drops_report_progress,
        .report_final = hits_drops_report_final,
};