#include "test-tool.h"
#include "cache.h"
#include "parse-options.h"

static int single;
static int multi;
static int count = 1;
static int dump;
static int perf;
static int analyze;
static int analyze_step;

/*
 * Dump the contents of the "dir" and "name" hash tables to stdout.
 * If you sort the result, you can compare it with the other type
 * mode and verify that both single and multi produce the same set.
 */
static void dump_run(void)
{
        struct hashmap_iter iter_dir;
        struct hashmap_iter iter_cache;

        /* Stolen from name-hash.c */
        struct dir_entry {
                struct hashmap_entry ent;
                struct dir_entry *parent;
                int nr;
                unsigned int namelen;
                char name[FLEX_ARRAY];
        };

        struct dir_entry *dir;
        struct cache_entry *ce;

        read_cache();
        if (single) {
                test_lazy_init_name_hash(&the_index, 0);
        } else {
                int nr_threads_used = test_lazy_init_name_hash(&the_index, 1);
                if (!nr_threads_used)
                        die("non-threaded code path used");
        }

        dir = hashmap_iter_first(&the_index.dir_hash, &iter_dir);
        while (dir) {
                printf("dir %08x %7d %s\n", dir->ent.hash, dir->nr, dir->name);
                dir = hashmap_iter_next(&iter_dir);
        }

        ce = hashmap_iter_first(&the_index.name_hash, &iter_cache);
        while (ce) {
                printf("name %08x %s\n", ce->ent.hash, ce->name);
                ce = hashmap_iter_next(&iter_cache);
        }

        discard_cache();
}

/*
 * Run the single or multi threaded version "count" times and
 * report on the time taken.
 */
static uint64_t time_runs(int try_threaded)
{
        uint64_t t0, t1, t2;
        uint64_t sum = 0;
        uint64_t avg;
        int nr_threads_used;
        int i;

        for (i = 0; i < count; i++) {
                t0 = getnanotime();
                read_cache();
                t1 = getnanotime();
                nr_threads_used = test_lazy_init_name_hash(&the_index, try_threaded);
                t2 = getnanotime();

                sum += (t2 - t1);

                if (try_threaded && !nr_threads_used)
                        die("non-threaded code path used");

                if (nr_threads_used)
                        printf("%f %f %d multi %d\n",
                                   ((double)(t1 - t0))/1000000000,
                                   ((double)(t2 - t1))/1000000000,
                                   the_index.cache_nr,
                                   nr_threads_used);
                else
                        printf("%f %f %d single\n",
                                   ((double)(t1 - t0))/1000000000,
                                   ((double)(t2 - t1))/1000000000,
                                   the_index.cache_nr);
                fflush(stdout);

                discard_cache();
        }

        avg = sum / count;
        if (count > 1)
                printf("avg %f %s\n",
                           (double)avg/1000000000,
                           (try_threaded) ? "multi" : "single");

        return avg;
}

/*
 * Try a series of runs varying the "istate->cache_nr" and
 * try to find a good value for the multi-threaded criteria.
 */
static void analyze_run(void)
{
        uint64_t t1s, t1m, t2s, t2m;
        int cache_nr_limit;
        int nr_threads_used = 0;
        int i;
        int nr;

        read_cache();
        cache_nr_limit = the_index.cache_nr;
        discard_cache();

        nr = analyze;
        while (1) {
                uint64_t sum_single = 0;
                uint64_t sum_multi = 0;
                uint64_t avg_single;
                uint64_t avg_multi;

                if (nr > cache_nr_limit)
                        nr = cache_nr_limit;

                for (i = 0; i < count; i++) {
                        read_cache();
                        the_index.cache_nr = nr; /* cheap truncate of index */
                        t1s = getnanotime();
                        test_lazy_init_name_hash(&the_index, 0);
                        t2s = getnanotime();
                        sum_single += (t2s - t1s);
                        the_index.cache_nr = cache_nr_limit;
                        discard_cache();

                        read_cache();
                        the_index.cache_nr = nr; /* cheap truncate of index */
                        t1m = getnanotime();
                        nr_threads_used = test_lazy_init_name_hash(&the_index, 1);
                        t2m = getnanotime();
                        sum_multi += (t2m - t1m);
                        the_index.cache_nr = cache_nr_limit;
                        discard_cache();

                        if (!nr_threads_used)
                                printf("    [size %8d] [single %f]   non-threaded code path used\n",
                                           nr, ((double)(t2s - t1s))/1000000000);
                        else
                                printf("    [size %8d] [single %f] %c [multi %f %d]\n",
                                           nr,
                                           ((double)(t2s - t1s))/1000000000,
                                           (((t2s - t1s) < (t2m - t1m)) ? '<' : '>'),
                                           ((double)(t2m - t1m))/1000000000,
                                           nr_threads_used);
                        fflush(stdout);
                }
                if (count > 1) {
                        avg_single = sum_single / count;
                        avg_multi = sum_multi / count;
                        if (!nr_threads_used)
                                printf("avg [size %8d] [single %f]\n",
                                           nr,
                                           (double)avg_single/1000000000);
                        else
                                printf("avg [size %8d] [single %f] %c [multi %f %d]\n",
                                           nr,
                                           (double)avg_single/1000000000,
                                           (avg_single < avg_multi ? '<' : '>'),
                                           (double)avg_multi/1000000000,
                                           nr_threads_used);
                        fflush(stdout);
                }

                if (nr >= cache_nr_limit)
                        return;
                nr += analyze_step;
        }
}

int cmd__lazy_init_name_hash(int argc, const char **argv)
{
        const char *usage[] = {
                "test-tool lazy-init-name-hash -d (-s | -m)",
                "test-tool lazy-init-name-hash -p [-c c]",
                "test-tool lazy-init-name-hash -a a [--step s] [-c c]",
                "test-tool lazy-init-name-hash (-s | -m) [-c c]",
                "test-tool lazy-init-name-hash -s -m [-c c]",
                NULL
        };
        struct option options[] = {
                OPT_BOOL('s', "single", &single, "run single-threaded code"),
                OPT_BOOL('m', "multi", &multi, "run multi-threaded code"),
                OPT_INTEGER('c', "count", &count, "number of passes"),
                OPT_BOOL('d', "dump", &dump, "dump hash tables"),
                OPT_BOOL('p', "perf", &perf, "compare single vs multi"),
                OPT_INTEGER('a', "analyze", &analyze, "analyze different multi sizes"),
                OPT_INTEGER(0, "step", &analyze_step, "analyze step factor"),
                OPT_END(),
        };
        const char *prefix;
        uint64_t avg_single, avg_multi;

        prefix = setup_git_directory();

        argc = parse_options(argc, argv, prefix, options, usage, 0);

        /*
         * istate->dir_hash is only created when ignore_case is set.
         */
        ignore_case = 1;

        if (dump) {
                if (perf || analyze > 0)
                        die("cannot combine dump, perf, or analyze");
                if (count > 1)
                        die("count not valid with dump");
                if (single && multi)
                        die("cannot use both single and multi with dump");
                if (!single && !multi)
                        die("dump requires either single or multi");
                dump_run();
                return 0;
        }

        if (perf) {
                if (analyze > 0)
                        die("cannot combine dump, perf, or analyze");
                if (single || multi)
                        die("cannot use single or multi with perf");
                avg_single = time_runs(0);
                avg_multi = time_runs(1);
                if (avg_multi > avg_single)
                        die("multi is slower");
                return 0;
        }

        if (analyze) {
                if (analyze < 500)
                        die("analyze must be at least 500");
                if (!analyze_step)
                        analyze_step = analyze;
                if (single || multi)
                        die("cannot use single or multi with analyze");
                analyze_run();
                return 0;
        }

        if (!single && !multi)
                die("require either -s or -m or both");

        if (single)
                time_runs(0);
        if (multi)
                time_runs(1);

        return 0;
}