// SPDX-License-Identifier: GPL-2.0-only
/*
 * benchmark.c:
 * Author: Konstantin Khlebnikov <koct9i@gmail.com>
 */
#include <linux/radix-tree.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <time.h>
#include "test.h"

#define NSEC_PER_SEC    1000000000L

static long long benchmark_iter(struct radix_tree_root *root, bool tagged)
{
        volatile unsigned long sink = 0;
        struct radix_tree_iter iter;
        struct timespec start, finish;
        long long nsec;
        int l, loops = 1;
        void **slot;

#ifdef BENCHMARK
again:
#endif
        clock_gettime(CLOCK_MONOTONIC, &start);
        for (l = 0; l < loops; l++) {
                if (tagged) {
                        radix_tree_for_each_tagged(slot, root, &iter, 0, 0)
                                sink ^= (unsigned long)slot;
                } else {
                        radix_tree_for_each_slot(slot, root, &iter, 0)
                                sink ^= (unsigned long)slot;
                }
        }
        clock_gettime(CLOCK_MONOTONIC, &finish);

        nsec = (finish.tv_sec - start.tv_sec) * NSEC_PER_SEC +
               (finish.tv_nsec - start.tv_nsec);

#ifdef BENCHMARK
        if (loops == 1 && nsec * 5 < NSEC_PER_SEC) {
                loops = NSEC_PER_SEC / nsec / 4 + 1;
                goto again;
        }
#endif

        nsec /= loops;
        return nsec;
}

static void benchmark_insert(struct radix_tree_root *root,
                             unsigned long size, unsigned long step)
{
        struct timespec start, finish;
        unsigned long index;
        long long nsec;

        clock_gettime(CLOCK_MONOTONIC, &start);

        for (index = 0 ; index < size ; index += step)
                item_insert(root, index);

        clock_gettime(CLOCK_MONOTONIC, &finish);

        nsec = (finish.tv_sec - start.tv_sec) * NSEC_PER_SEC +
               (finish.tv_nsec - start.tv_nsec);

        printv(2, "Size: %8ld, step: %8ld, insertion: %15lld ns\n",
                size, step, nsec);
}

static void benchmark_tagging(struct radix_tree_root *root,
                             unsigned long size, unsigned long step)
{
        struct timespec start, finish;
        unsigned long index;
        long long nsec;

        clock_gettime(CLOCK_MONOTONIC, &start);

        for (index = 0 ; index < size ; index += step)
                radix_tree_tag_set(root, index, 0);

        clock_gettime(CLOCK_MONOTONIC, &finish);

        nsec = (finish.tv_sec - start.tv_sec) * NSEC_PER_SEC +
               (finish.tv_nsec - start.tv_nsec);

        printv(2, "Size: %8ld, step: %8ld, tagging: %17lld ns\n",
                size, step, nsec);
}

static void benchmark_delete(struct radix_tree_root *root,
                             unsigned long size, unsigned long step)
{
        struct timespec start, finish;
        unsigned long index;
        long long nsec;

        clock_gettime(CLOCK_MONOTONIC, &start);

        for (index = 0 ; index < size ; index += step)
                item_delete(root, index);

        clock_gettime(CLOCK_MONOTONIC, &finish);

        nsec = (finish.tv_sec - start.tv_sec) * NSEC_PER_SEC +
               (finish.tv_nsec - start.tv_nsec);

        printv(2, "Size: %8ld, step: %8ld, deletion: %16lld ns\n",
                size, step, nsec);
}

static void benchmark_size(unsigned long size, unsigned long step)
{
        RADIX_TREE(tree, GFP_KERNEL);
        long long normal, tagged;

        benchmark_insert(&tree, size, step);
        benchmark_tagging(&tree, size, step);

        tagged = benchmark_iter(&tree, true);
        normal = benchmark_iter(&tree, false);

        printv(2, "Size: %8ld, step: %8ld, tagged iteration: %8lld ns\n",
                size, step, tagged);
        printv(2, "Size: %8ld, step: %8ld, normal iteration: %8lld ns\n",
                size, step, normal);

        benchmark_delete(&tree, size, step);

        item_kill_tree(&tree);
        rcu_barrier();
}

void benchmark(void)
{
        unsigned long size[] = {1 << 10, 1 << 20, 0};
        unsigned long step[] = {1, 2, 7, 15, 63, 64, 65,
                                128, 256, 512, 12345, 0};
        int c, s;

        printv(1, "starting benchmarks\n");
        printv(1, "RADIX_TREE_MAP_SHIFT = %d\n", RADIX_TREE_MAP_SHIFT);

        for (c = 0; size[c]; c++)
                for (s = 0; step[s]; s++)
                        benchmark_size(size[c], step[s]);
}