Files
littlefs/runners/bench_runner.h
T
Christopher Haster c648f96dc5 Added check_progs for immediate prog validation
This configuration option enables the previous behavior of reading back
every prog to check that the data was written correctly.

Unfortunately, this brings a bit of baggage, thanks to our cache
interactions being more complicated now:

- We really want to reuse the rcache for prog validation, despite the
  cache performance implications. Unfortunately, we simply can't, thanks
  to the new bd utility functions tying up the rcache. lfsr_bd_cpy, for
  example, does not expect rcache to be invalidated between a read and
  prog, and if it is, things break (I may or may not have found this by
  experience).

  These bd utilities are valuable, so we really need some other way to
  validate our progs.

- Since we can't rely on the rcache, this leaves checksumming as the
  only option for validating progs. Checksumming isn't perfect, as there
  is a decent chance of false negatives, but to be honest it's probably
  good enough for anything that's not malicious.

- This also adds the new constraint that we need to be able to read back
  any prog into the pcache, which implies read_size <= prog_size. This
  constraint didn't exist when we could clobber our rcache, but this is
  not worth throwing away the new bd utilities. Not to mention
  clobbering our rcache could hurt cache performance.

  Why not make read_size <= prog_size conditional on check_progs?

  The main reason is convenience. One very compelling use case for
  check_progs is to help debug unknown filesystem/integration failures,
  buf if you can't enable check_progs without changing the filesystem
  configuration, you can't really rely on check_progs for debugging.

  This helps future proof what we expect from block devices, in case
  future error detection/correction mechanisms can benefit from our
  prog_size always being readable.

Code changes were not that significant, however there was a surprising
stack cost. This seems to be because lfsr_bd_read__ can now be called
from multiple places, causing it to no longer be inlined in
lfsr_bd_read_, costing a bit of stack for the additional function call:

  before: 33566           2624
  after:  33682 (+0.3%)   2640 (+0.6%)
2024-05-29 23:09:41 -05:00

164 lines
5.3 KiB
C

/*
* Runner for littlefs benchmarks
*
* Copyright (c) 2022, The littlefs authors.
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef BENCH_RUNNER_H
#define BENCH_RUNNER_H
// override LFS_TRACE
void bench_trace(const char *fmt, ...);
#define LFS_TRACE_(fmt, ...) \
bench_trace("%s:%d:trace: " fmt "%s\n", \
__FILE__, \
__LINE__, \
__VA_ARGS__)
#define LFS_TRACE(...) LFS_TRACE_(__VA_ARGS__, "")
#define LFS_EMUBD_TRACE(...) LFS_TRACE_(__VA_ARGS__, "")
// BENCH_START/BENCH_STOP macros measure readed/proged/erased bytes
// through emubd
void bench_start(const char *meas, uintmax_t iter, uintmax_t size);
void bench_stop(const char *meas);
#define BENCH_START(meas, iter, size) \
bench_start(meas, iter, size)
#define BENCH_STOP(meas) \
bench_stop(meas)
// BENCH_RESULT/BENCH_FRESULT allow for explicit non-io measurements
void bench_result(const char *meas, uintmax_t iter, uintmax_t size,
uintmax_t result);
void bench_fresult(const char *meas, uintmax_t iter, uintmax_t size,
double result);
#define BENCH_RESULT(meas, iter, size, result) \
bench_result(meas, iter, size, result)
#define BENCH_FRESULT(meas, iter, size, result) \
bench_fresult(meas, iter, size, result)
// note these are indirectly included in any generated files
#include "bd/lfs_emubd.h"
#include <stdio.h>
// give source a chance to define feature macros
#undef _FEATURES_H
#undef _STDIO_H
// generated bench configurations
struct lfs_config;
enum bench_flags {
BENCH_INTERNAL = 0x1,
};
typedef uint8_t bench_flags_t;
typedef struct bench_define {
const char *name;
intmax_t *define;
intmax_t (*cb)(void *data, size_t i);
void *data;
size_t permutations;
} bench_define_t;
struct bench_case {
const char *name;
const char *path;
bench_flags_t flags;
const bench_define_t *defines;
size_t permutations;
bool (*if_)(void);
void (*run)(struct lfs_config *cfg);
};
struct bench_suite {
const char *name;
const char *path;
bench_flags_t flags;
const bench_define_t *defines;
size_t define_count;
const struct bench_case *cases;
size_t case_count;
};
extern const struct bench_suite *const bench_suites[];
extern const size_t bench_suite_count;
// deterministic prng for pseudo-randomness in benches
uint32_t bench_prng(uint32_t *state);
#define BENCH_PRNG(state) bench_prng(state)
// generation of specific permutations of an array for exhaustive benching
size_t bench_factorial(size_t x);
void bench_permutation(size_t i, uint32_t *buffer, size_t size);
#define BENCH_FACTORIAL(x) bench_factorial(x)
#define BENCH_PERMUTATION(i, buffer, size) bench_permutation(i, buffer, size)
// a few preconfigured defines that control how benches run
#define BENCH_IMPLICIT_DEFINES \
/* name value (overridable) */ \
BENCH_DEFINE(READ_SIZE, 1 ) \
BENCH_DEFINE(PROG_SIZE, 1 ) \
BENCH_DEFINE(BLOCK_SIZE, 4096 ) \
BENCH_DEFINE(BLOCK_COUNT, DISK_SIZE/BLOCK_SIZE ) \
BENCH_DEFINE(DISK_SIZE, 1024*1024 ) \
BENCH_DEFINE(BLOCK_RECYCLES, -1 ) \
BENCH_DEFINE(RCACHE_SIZE, LFS_MAX(16, READ_SIZE) ) \
BENCH_DEFINE(PCACHE_SIZE, LFS_MAX(16, PROG_SIZE) ) \
BENCH_DEFINE(FBUFFER_SIZE, 16 ) \
BENCH_DEFINE(LOOKAHEAD_SIZE, 16 ) \
BENCH_DEFINE(INLINE_SIZE, BLOCK_SIZE/4 ) \
BENCH_DEFINE(SHRUB_SIZE, INLINE_SIZE ) \
BENCH_DEFINE(FRAGMENT_SIZE, BLOCK_SIZE/8 ) \
BENCH_DEFINE(CRYSTAL_THRESH, BLOCK_SIZE/8 ) \
BENCH_DEFINE(CHECK_PROGS, false ) \
BENCH_DEFINE(ERASE_VALUE, 0xff ) \
BENCH_DEFINE(ERASE_CYCLES, 0 ) \
BENCH_DEFINE(BADBLOCK_BEHAVIOR, LFS_EMUBD_BADBLOCK_PROGERROR ) \
BENCH_DEFINE(POWERLOSS_BEHAVIOR, LFS_EMUBD_POWERLOSS_NOOP )
// declare defines as global intmax_ts
#define BENCH_DEFINE(k, v) \
extern intmax_t k;
BENCH_IMPLICIT_DEFINES
#undef BENCH_DEFINE
// map defines to cfg struct fields
#define BENCH_CFG \
.read_size = READ_SIZE, \
.prog_size = PROG_SIZE, \
.block_size = BLOCK_SIZE, \
.block_count = BLOCK_COUNT, \
.block_recycles = BLOCK_RECYCLES, \
.rcache_size = RCACHE_SIZE, \
.pcache_size = PCACHE_SIZE, \
.fbuffer_size = FBUFFER_SIZE, \
.lookahead_size = LOOKAHEAD_SIZE, \
.inline_size = INLINE_SIZE, \
.shrub_size = SHRUB_SIZE, \
.fragment_size = FRAGMENT_SIZE, \
.crystal_thresh = CRYSTAL_THRESH, \
.check_progs = CHECK_PROGS,
#define BENCH_BDCFG \
.erase_value = ERASE_VALUE, \
.erase_cycles = ERASE_CYCLES, \
.badblock_behavior = BADBLOCK_BEHAVIOR,
#endif