Files
littlefs/benches/bench_wt.toml
T
Christopher Haster 1a98d8089b benches: Reworked bench_rt to fail gracefully
This reworks bench_rt to write the target file gradually, mixing reads
and writes. This makes it so if the benchmark times out, the results are
still interesting, if less rigorous.

This is useful if you want to compare a change quickly, with more
SIM_TIME leading to a more accurate result.

---

The problem for bench_rt is that we first need to write a file. This can
take _quite_ a while for large SIM_TIME, completely failing in some
cases (bench_rt_many + BENCH_NAND).

The nice thing about bench_wt is that when it fails you still get
interesting numbers out of it. You don't find the relevant throughput
for the given SIZE, but you do find throughput for files _approaching_
SIZE. Unfortunately this didn't carry over to bench_rt.

The good news is the new bench probe system makes it easy to selectively
ignore parts of each bench, so we can rework bench_rt to start with a
CHUNK sized file and gradually increase it until it hits our target
size. This allows bench_rt to also fail gracefully.

Consider a 1 minute run:

  $ make bench-runner -j \
      && BENCHFLAGS='bench_rt -DSIM_TIME=60000000000' make bench -j \
      && make bench-marks
  bench+probe                            n       t  throughput
  bench_rt_seq+read                 302848     0.0  30690155.6
  bench_rt_random+read              302592     0.0  59646605.2
  bench_rt_logging+read              52992     5.9      8915.0
  bench_rt_many+read                112896     0.2    482831.6
  TOTAL                             771328     6.2  22707126.8

Vs the default 1 hour run:

  $ make bench-runner -j \
      && BENCHFLAGS='bench_rt' make bench -j \
      && make bench-marks
  bench+probe                            n       t  throughput
  bench_rt_seq+read            79600038272  3325.1  23939212.7
  bench_rt_random+read         21482635264  3325.0   6461004.1
  bench_rt_logging+read            3085056   740.9      4163.9
  bench_rt_many+read             706571904  1800.7    392380.4
  TOTAL                       101792330496  9191.7   7699190.3

The main risk of doing this is cross-contaminating read results with
write operations. Fortunately the current benches appear to be isolated
well enough:

  $ make bench-ops
  bench+probe                       readed     progged      erased
  bench_rt_logging+read           86886137    18936138    19767296
  bench_rt_seq+read            83127251476           0           0
  bench_rt_many+read           45018292401           0           0
  bench_rt_random+read         83124213669           0           0
  TOTAL                       211356643683    18936138    19767296

---

Oh! This also lets us add bench_rt_logging, which needs a mixed writer
to make any sense.

Note bench_rt_logging also includes popping from the log (fifo?), so is
not a strictly read-only bench.
2026-03-09 22:55:31 -05:00

339 lines
9.9 KiB
TOML

# High-level write-throughput benchmarks
after = ['bench_file', 'bench_dir']
# these are common and can be overridden suite-wide
#
# note for bench_*_many, file size defaults to CHUNK, and SIZE = sum of
# all files
#
defines.SIZE = '1024*1024' # 1 MiB
defines.CHUNK = 64
defines.SEED = 42
# simulated time, in nanoseconds, to run the bench
defines.SIM_TIME = '60ULL*60ULL*1000ULL*1000ULL*1000ULL' # 1 hour
# simulation size in bytes
defines.SIM_SIZE = 0
# set this to true to skip bench warmup
defines.SKIP_WARMUP = false
# include common bench helpers
code = '''
#include "benches/bench_helpers.h"
'''
# sequential write throughput
[cases.bench_wt_seq]
code = '''
lfs3_t lfs3;
lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
if (!SKIP_WARMUP) {
BENCH_STACK_PAUSE();
BENCH_HEAP_PAUSE();
int err = bench_helpers_warmup(&lfs3);
if (err) {
LFS3_ERROR("Bench warmup failed: %d", err);
return;
}
BENCH_HEAP_RESUME();
BENCH_STACK_RESUME();
}
uint32_t prng = SEED;
// reset our timer
BENCH_SIMRESET();
// open a file
BENCH_START("write");
lfs3_file_t file;
lfs3_file_open(&lfs3, &file, "bench_seq",
LFS3_O_WRONLY | LFS3_O_CREAT | LFS3_O_EXCL) => 0;
lfs3_off_t size = 0;
uint64_t written = 0;
BENCH_STOP("write", written);
// ok, one of these needs to be non-zero
LFS3_ASSERT(SIM_TIME > 0 || SIM_SIZE > 0);
while (!(SIM_SIZE && written >= (uint64_t)SIM_SIZE)
&& !(SIM_TIME && BENCH_SIMTIME() >= SIM_TIME)) {
BENCH_START("write");
// arguably we should just rewind and continue writing to the
// front of the file when we hit the end, but this overly
// penalizes littlefs2, so instead we truncate
if (size >= SIZE) {
lfs3_file_rewind(&lfs3, &file) => 0;
lfs3_file_truncate(&lfs3, &file, 0) => 0;
size = 0;
}
// write to the file
uint8_t wbuf[CHUNK];
for (lfs3_size_t j = 0; j < CHUNK; j++) {
wbuf[j] = 'a' + (BENCH_PRNG(&prng) % 26);
}
lfs3_file_write(&lfs3, &file, wbuf, CHUNK) => CHUNK;
size += CHUNK;
written += CHUNK;
BENCH_STOP("write", written);
}
BENCH_START("write");
lfs3_file_close(&lfs3, &file) => 0;
// report the amount we managed to write
BENCH_STOP("write", written);
// report the total stack/heap usage after the benchmark
#ifdef BENCH_STACK
BENCH_RESULT("stack", written, BENCH_STACK_WATERMARK());
#endif
#ifdef BENCH_HEAP
BENCH_RESULT("heap", written, BENCH_HEAP_WATERMARK());
#endif
// find the total disk usage after the benchmark
//
// note this is garbage because of the above truncates!
uintmax_t usage = bench_helpers_usage(&lfs3);
BENCH_RESULT("usage", written, usage);
lfs3_unmount(&lfs3) => 0;
'''
# random write throughput
[cases.bench_wt_random]
code = '''
lfs3_t lfs3;
lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
if (!SKIP_WARMUP) {
BENCH_STACK_PAUSE();
BENCH_HEAP_PAUSE();
int err = bench_helpers_warmup(&lfs3);
if (err) {
return;
}
BENCH_HEAP_RESUME();
BENCH_STACK_RESUME();
}
uint32_t prng = SEED;
// reset our timer
BENCH_SIMRESET();
// open a file
BENCH_START("write");
lfs3_file_t file;
lfs3_file_open(&lfs3, &file, "bench_random",
LFS3_O_WRONLY | LFS3_O_CREAT | LFS3_O_EXCL) => 0;
lfs3_off_t size = 0;
uint64_t written = 0;
BENCH_STOP("write", written);
// ok, one of these needs to be non-zero
LFS3_ASSERT(SIM_TIME > 0 || SIM_SIZE > 0);
while (!(SIM_SIZE && written >= (uint64_t)SIM_SIZE)
&& !(SIM_TIME && BENCH_SIMTIME() >= SIM_TIME)) {
BENCH_START("write");
// seek to a random location
lfs3_off_t pos = BENCH_PRNG(&prng) % SIZE;
lfs3_file_seek(&lfs3, &file, pos, LFS3_SEEK_SET) => pos;
// write to the file
uint8_t wbuf[CHUNK];
for (lfs3_size_t j = 0; j < CHUNK; j++) {
wbuf[j] = 'a' + (BENCH_PRNG(&prng) % 26);
}
lfs3_file_write(&lfs3, &file, wbuf, CHUNK) => CHUNK;
size = lfs3_max(size, pos + CHUNK);
written += CHUNK;
BENCH_STOP("write", written);
}
BENCH_START("write");
lfs3_file_close(&lfs3, &file) => 0;
// report the amount we managed to write
BENCH_STOP("write", written);
// report the total stack/heap usage after the benchmark
#ifdef BENCH_STACK
BENCH_RESULT("stack", written, BENCH_STACK_WATERMARK());
#endif
#ifdef BENCH_HEAP
BENCH_RESULT("heap", written, BENCH_HEAP_WATERMARK());
#endif
// find the total disk usage after the benchmark
uintmax_t usage = bench_helpers_usage(&lfs3);
BENCH_RESULT("usage", written, usage);
lfs3_unmount(&lfs3) => 0;
'''
# logging write throughput
#
# two big differences from seq:
# 1. fruncate/rotations instead of rewind+truncate
# 2. sync called on every write
[cases.bench_wt_logging]
defines.NO_FRUNCATE = false
code = '''
lfs3_t lfs3;
lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
if (!SKIP_WARMUP) {
BENCH_STACK_PAUSE();
BENCH_HEAP_PAUSE();
int err = bench_helpers_warmup(&lfs3);
if (err) {
return;
}
BENCH_HEAP_RESUME();
BENCH_STACK_RESUME();
}
uint32_t prng = SEED;
// reset our timer
BENCH_SIMRESET();
// open a file
BENCH_START("write");
lfs3_file_t file;
lfs3_file_open(&lfs3, &file, "bench_log",
LFS3_O_WRONLY | LFS3_O_CREAT | LFS3_O_EXCL | LFS3_O_APPEND) => 0;
uint64_t written = 0;
BENCH_STOP("write", written);
// ok, one of these needs to be non-zero
LFS3_ASSERT(SIM_TIME > 0 || SIM_SIZE > 0);
while (!(SIM_SIZE && written >= (uint64_t)SIM_SIZE)
&& !(SIM_TIME && BENCH_SIMTIME() >= SIM_TIME)) {
BENCH_START("write");
// append to log
uint8_t wbuf[CHUNK];
for (lfs3_size_t j = 0; j < CHUNK; j++) {
wbuf[j] = 'a' + (BENCH_PRNG(&prng) % 26);
}
lfs3_file_write(&lfs3, &file, wbuf, CHUNK) => CHUNK;
// sync
lfs3_file_sync(&lfs3, &file) => 0;
// fruncate or rotate if full
lfs3_soff_t size = lfs3_file_size(&lfs3, &file);
assert(size >= 0);
if (size > SIZE) {
if (!NO_FRUNCATE) {
lfs3_file_fruncate(&lfs3, &file, SIZE) => 0;
} else {
lfs3_file_close(&lfs3, &file) => 0;
lfs3_rename(&lfs3, "bench_log", "bench_log.1") => 0;
lfs3_file_open(&lfs3, &file, "bench_log",
LFS3_O_WRONLY
| LFS3_O_CREAT
| LFS3_O_EXCL
| LFS3_O_APPEND) => 0;
}
}
written += CHUNK;
BENCH_STOP("write", written);
}
BENCH_START("write");
lfs3_file_close(&lfs3, &file) => 0;
// report the amount we managed to write
BENCH_STOP("write", written);
// report the total stack/heap usage after the benchmark
#ifdef BENCH_STACK
BENCH_RESULT("stack", written, BENCH_STACK_WATERMARK());
#endif
#ifdef BENCH_HEAP
BENCH_RESULT("heap", written, BENCH_HEAP_WATERMARK());
#endif
// find the total disk usage after the benchmark
uintmax_t usage = bench_helpers_usage(&lfs3);
BENCH_RESULT("usage", written, usage);
lfs3_unmount(&lfs3) => 0;
'''
# many small file write throughput
[cases.bench_wt_many]
defines.FILE_SIZE = 'CHUNK'
defines.FILE_COUNT = '(SIZE+(FILE_SIZE-1)) / lfs3_max(FILE_SIZE, 1)'
code = '''
lfs3_t lfs3;
lfs3_format(&lfs3, LFS3_F_RDWR, CFG) => 0;
lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
if (!SKIP_WARMUP) {
BENCH_STACK_PAUSE();
BENCH_HEAP_PAUSE();
int err = bench_helpers_warmup(&lfs3);
if (err) {
return;
}
BENCH_HEAP_RESUME();
BENCH_STACK_RESUME();
}
uint32_t prng = SEED;
// reset our timer
BENCH_SIMRESET();
BENCH_START("write");
uint64_t written = 0;
BENCH_STOP("write", written);
// ok, one of these needs to be non-zero
LFS3_ASSERT(SIM_TIME > 0 || SIM_SIZE > 0);
while (!(SIM_SIZE && written >= (uint64_t)SIM_SIZE)
&& !(SIM_TIME && BENCH_SIMTIME() >= SIM_TIME)) {
BENCH_START("write");
// choose a random filename
lfs3_off_t pos = BENCH_PRNG(&prng) % FILE_COUNT;
char name[256];
sprintf(name, "bench_%08x", pos);
uint8_t wbuf[CHUNK];
// create the file
//
// note file == CHUNK here, the sum of all files should add up
// roughly to the benchmark SIZE
lfs3_file_t file;
lfs3_file_open(&lfs3, &file, name,
LFS3_O_WRONLY | LFS3_O_CREAT | LFS3_O_TRUNC) => 0;
for (lfs3_size_t i = 0; i < (FILE_SIZE+(CHUNK-1))/CHUNK; i++) {
lfs3_ssize_t d = lfs3_min(CHUNK, FILE_SIZE);
memset(wbuf, 'a'+(BENCH_PRNG(&prng) % 26), d);
lfs3_file_write(&lfs3, &file, wbuf, d) => d;
written += d;
// taking too long?
if (SIM_TIME && BENCH_SIMTIME() >= SIM_TIME) {
break;
}
}
lfs3_file_close(&lfs3, &file) => 0;
BENCH_STOP("write", written);
}
BENCH_START("write");
// report the amount we managed to write
BENCH_STOP("write", written);
// report the total stack/heap usage after the benchmark
#ifdef BENCH_STACK
BENCH_RESULT("stack", written, BENCH_STACK_WATERMARK());
#endif
#ifdef BENCH_HEAP
BENCH_RESULT("heap", written, BENCH_HEAP_WATERMARK());
#endif
// find the total disk usage after the benchmark
uintmax_t usage = bench_helpers_usage(&lfs3);
BENCH_RESULT("usage", written, usage);
lfs3_unmount(&lfs3) => 0;
'''