Files
littlefs/runners/bench_runner.h
T
Christopher Haster fc486ca4f7 Reworked lfsr_fs_gc to be incremental
Thinking about use case a bit, most lfsr_fs_gc will be to perform
background work, and can benefit from being incremental.

We already support incremental gc and all the mess associated with
traversal invalidation via the traversal API, so we might as well expose
this through lfsr_fs_gc.

The main downside is that we need to store an lfsr_traversal_t object
somewhere, which is not exactly a cheap struct. I was originally
considering limiting incremental gc to the traversal API for this
reason, but I think the value add of an incremental lfsr_fs_gc is too
compelling... Though we really should add a compile-time option
(LFS_NO_GC? LFS_NO_INCRGC?) to allow users to opt-out of this RAM cost
if they're never going to call this function.

Oh, and lfs_t also becomes self-referential, which might become a
problem for higher-level language users...

---

The incremental behavior of lfsr_fs_gc can be controlled by the new
gc_steps config option. This allows more than one step to be performed
at a time, which may allow for more progress when intermixed with
write-heavy filesystem operations. Setting gc_steps=-1 performs a full
traversal every call, which guarantees always making some amount of
progress.

This adds a bit of code, since we now need to check for/resume existing
traversals. But the real cost is the added RAM to lfs_t, which is
unfortunately wasted if you never call lfsr_fs_gc:

          code           stack          lfs_t
  before: 35708           2672            164
  after:  35756 (+0.1%)   2672 (+0.0%)    296 (+80.5%)
2024-07-17 18:08:32 -05:00

171 lines
5.8 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(FILE_BUFFER_SIZE, 16 ) \
BENCH_DEFINE(LOOKAHEAD_SIZE, 16 ) \
BENCH_DEFINE(GC_STEPS, 0 ) \
BENCH_DEFINE(GC_COMPACT_THRESH, 0 ) \
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 ) \
BENCH_DEFINE(EMUBD_SEED, 0 )
// 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, \
.file_buffer_size = FILE_BUFFER_SIZE, \
.lookahead_size = LOOKAHEAD_SIZE, \
.gc_steps = GC_STEPS, \
.gc_compact_thresh = GC_COMPACT_THRESH, \
.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, \
.powerloss_behavior = POWERLOSS_BEHAVIOR, \
.seed = EMUBD_SEED,
#endif