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git/t/helper/test-tool.c
Victoria Dye 94fcf0e852 cache-tree: add perf test comparing update and prime
Add a performance test comparing the execution times of 'prime_cache_tree()'
and 'cache_tree_update(_, WRITE_TREE_SILENT | WRITE_TREE_REPAIR)'. The goal
of comparing these two is to identify which is the faster method for
rebuilding an invalid cache tree, ultimately to remove one when both are
(reundantly) called in immediate succession.

Both methods are fast, so the new tests in 'p0090-cache-tree.sh' must call
each tested function multiple times to ensure the reported times (to 0.01s
resolution) convey the differences between them.

The tests compare the timing of a 'test-tool cache-tree' run as a no-op (to
capture a baseline for the overhead associated with running the tool),
'cache_tree_update()', and 'prime_cache_tree()' on four scenarios:

- A completely valid cache tree
- A cache tree with 2 invalid paths
- A cache tree with 50 invalid paths
- A completely empty cache tree

Example results:

Test                                        this tree
-----------------------------------------------------------
0090.2: no-op, clean                        1.27(0.48+0.52)
0090.3: prime_cache_tree, clean             2.02(0.83+0.85)
0090.4: cache_tree_update, clean            1.30(0.49+0.54)
0090.5: no-op, invalidate 2                 1.29(0.48+0.54)
0090.6: prime_cache_tree, invalidate 2      1.98(0.81+0.83)
0090.7: cache_tree_update, invalidate 2     2.12(0.94+0.86)
0090.8: no-op, invalidate 50                1.32(0.50+0.55)
0090.9: prime_cache_tree, invalidate 50     2.10(0.86+0.89)
0090.10: cache_tree_update, invalidate 50   2.35(1.14+0.90)
0090.11: no-op, empty                       1.33(0.50+0.54)
0090.12: prime_cache_tree, empty            2.04(0.84+0.87)
0090.13: cache_tree_update, empty           2.51(1.27+0.92)

These timings show that, while 'cache_tree_update()' is faster when the
cache tree is completely valid, it is equal to or slower than
'prime_cache_tree()' when there are any invalid paths. Since the redundant
calls are mostly in scenarios where the cache tree will be at least
partially invalid (e.g., 'git reset --hard'), 'prime_cache_tree()' will
likely perform better than 'cache_tree_update()' in typical cases.

Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-11-10 21:49:33 -05:00

141 lines
4.2 KiB
C

#include "git-compat-util.h"
#include "test-tool.h"
#include "test-tool-utils.h"
#include "trace2.h"
#include "parse-options.h"
static const char * const test_tool_usage[] = {
"test-tool [-C <directory>] <command [<arguments>...]]",
NULL
};
static struct test_cmd cmds[] = {
{ "advise", cmd__advise_if_enabled },
{ "bitmap", cmd__bitmap },
{ "bloom", cmd__bloom },
{ "bundle-uri", cmd__bundle_uri },
{ "cache-tree", cmd__cache_tree },
{ "chmtime", cmd__chmtime },
{ "config", cmd__config },
{ "crontab", cmd__crontab },
{ "csprng", cmd__csprng },
{ "ctype", cmd__ctype },
{ "date", cmd__date },
{ "delta", cmd__delta },
{ "dir-iterator", cmd__dir_iterator },
{ "drop-caches", cmd__drop_caches },
{ "dump-cache-tree", cmd__dump_cache_tree },
{ "dump-fsmonitor", cmd__dump_fsmonitor },
{ "dump-split-index", cmd__dump_split_index },
{ "dump-untracked-cache", cmd__dump_untracked_cache },
{ "example-decorate", cmd__example_decorate },
{ "fast-rebase", cmd__fast_rebase },
{ "fsmonitor-client", cmd__fsmonitor_client },
{ "genrandom", cmd__genrandom },
{ "genzeros", cmd__genzeros },
{ "getcwd", cmd__getcwd },
{ "hashmap", cmd__hashmap },
{ "hash-speed", cmd__hash_speed },
{ "hexdump", cmd__hexdump },
{ "index-version", cmd__index_version },
{ "json-writer", cmd__json_writer },
{ "lazy-init-name-hash", cmd__lazy_init_name_hash },
{ "match-trees", cmd__match_trees },
{ "mergesort", cmd__mergesort },
{ "mktemp", cmd__mktemp },
{ "oid-array", cmd__oid_array },
{ "oidmap", cmd__oidmap },
{ "oidtree", cmd__oidtree },
{ "online-cpus", cmd__online_cpus },
{ "pack-mtimes", cmd__pack_mtimes },
{ "parse-options", cmd__parse_options },
{ "parse-options-flags", cmd__parse_options_flags },
{ "parse-pathspec-file", cmd__parse_pathspec_file },
{ "parse-subcommand", cmd__parse_subcommand },
{ "partial-clone", cmd__partial_clone },
{ "path-utils", cmd__path_utils },
{ "pcre2-config", cmd__pcre2_config },
{ "pkt-line", cmd__pkt_line },
{ "prio-queue", cmd__prio_queue },
{ "proc-receive", cmd__proc_receive },
{ "progress", cmd__progress },
{ "reach", cmd__reach },
{ "read-cache", cmd__read_cache },
{ "read-graph", cmd__read_graph },
{ "read-midx", cmd__read_midx },
{ "ref-store", cmd__ref_store },
{ "reftable", cmd__reftable },
{ "rot13-filter", cmd__rot13_filter },
{ "dump-reftable", cmd__dump_reftable },
{ "regex", cmd__regex },
{ "repository", cmd__repository },
{ "revision-walking", cmd__revision_walking },
{ "run-command", cmd__run_command },
{ "scrap-cache-tree", cmd__scrap_cache_tree },
{ "serve-v2", cmd__serve_v2 },
{ "sha1", cmd__sha1 },
{ "sha256", cmd__sha256 },
{ "sigchain", cmd__sigchain },
{ "simple-ipc", cmd__simple_ipc },
{ "strcmp-offset", cmd__strcmp_offset },
{ "string-list", cmd__string_list },
{ "submodule", cmd__submodule },
{ "submodule-config", cmd__submodule_config },
{ "submodule-nested-repo-config", cmd__submodule_nested_repo_config },
{ "subprocess", cmd__subprocess },
{ "trace2", cmd__trace2 },
{ "userdiff", cmd__userdiff },
{ "urlmatch-normalization", cmd__urlmatch_normalization },
{ "xml-encode", cmd__xml_encode },
{ "wildmatch", cmd__wildmatch },
#ifdef GIT_WINDOWS_NATIVE
{ "windows-named-pipe", cmd__windows_named_pipe },
#endif
{ "write-cache", cmd__write_cache },
};
static NORETURN void die_usage(void)
{
size_t i;
fprintf(stderr, "usage: test-tool <toolname> [args]\n");
for (i = 0; i < ARRAY_SIZE(cmds); i++)
fprintf(stderr, " %s\n", cmds[i].name);
exit(128);
}
int cmd_main(int argc, const char **argv)
{
int i;
const char *working_directory = NULL;
struct option options[] = {
OPT_STRING('C', NULL, &working_directory, "directory",
"change the working directory"),
OPT_END()
};
BUG_exit_code = 99;
argc = parse_options(argc, argv, NULL, options, test_tool_usage,
PARSE_OPT_STOP_AT_NON_OPTION |
PARSE_OPT_KEEP_ARGV0);
if (argc < 2)
die_usage();
if (working_directory && chdir(working_directory) < 0)
die("Could not cd to '%s'", working_directory);
for (i = 0; i < ARRAY_SIZE(cmds); i++) {
if (!strcmp(cmds[i].name, argv[1])) {
argv++;
argc--;
trace2_cmd_name(cmds[i].name);
trace2_cmd_list_config();
trace2_cmd_list_env_vars();
return cmds[i].fn(argc, argv);
}
}
error("there is no tool named '%s'", argv[1]);
die_usage();
}