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c44427f9ec93e95176df6dfa3a3f065a99504be2
thirdparty-littlefs/tests/test_exhaustion.toml
Christopher Haster c44427f9ec Exploring ideas for static configuration 
As an embedded library, littlefs's configuration straddles two worlds.
In most cases the configuration is usually constant at build time, but
when integrated into OSs, the configuration needs to be dynamically
configurable.

To help with this, littlefs has a separate lfs_config struct that can be
placed into ROM when possible.

But you know what's better than ROM configuration? Truely inlinable
static configuration known at compile-time. In addition to avoiding the
RAM cost, compile-time configuration allows for additional compiler
optimizations, such as constexpr-elimination and removal of unused
code-paths.

So how to enable static configuration?

1. define LFS_STATICCFG
2. implement callbacks as global functions:
   - lfs_read
   - lfs_prog
   - lfs_erase
   - lfs_sync
2. define the now-required constants that configure littlefs:
   - LFS_READ_SIZE
   - LFS_PROG_SIZE
   - LFS_BLOCK_SIZE
   - LFS_BLOCK_COUNT
   - LFS_BLOCK_CYCLES
   - LFS_CACHE_SIZE
   - LFS_LOOKAHEAD_SIZE
   - LFS_READ_BUFFER (optional)
   - LFS_PROG_BUFFER (optional)
   - LFS_LOOKAHEAD_BUFFER (optional)
   - LFS_NAME_MAX (optional)
   - LFS_FILE_MAX (optional)
   - LFS_ATTR_MAX (optional)

Note, there is a separate configuration for the file configuration, this
can be enabled/disabled independently of LFS_STATICCFG. You will likely
want to define this as well if you are looking for the smallest code
size.

In order to avoid a mess of #ifdefs, the internals of littlefs use a
simple macro that redirects to either the dynamic or static config at
compile time:

    #ifdef LFS_STATICCFG
    #define LFS_CFG_READ_SIZE(lfs) ((void)lfs, LFS_READ_SIZE)
    #else
    #define LFS_CFG_READ_SIZE(lfs) lfs->cfg->read_size
    #endif

Unfortunately it does look like there still may be a lot of issues
related to warnings of comparisons against constants... If only C had
a way to ignore warnings on individual statements...

Original idea by apmorton
2020-11-28 19:15:24 -06:00

466 lines
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[[case]] # test running a filesystem to exhaustion
define.LFS_ERASE_CYCLES = 10
define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
define.LFS_BADBLOCK_BEHAVIOR = [
'LFS_TESTBD_BADBLOCK_PROGERROR',
'LFS_TESTBD_BADBLOCK_ERASEERROR',
'LFS_TESTBD_BADBLOCK_READERROR',
'LFS_TESTBD_BADBLOCK_PROGNOOP',
'LFS_TESTBD_BADBLOCK_ERASENOOP',
]
define.FILES = 10
code = '''
lfs_formatcfg(&lfs, &cfg) => 0;
lfs_mountcfg(&lfs, &cfg) => 0;
lfs_mkdir(&lfs, "roadrunner") => 0;
lfs_unmount(&lfs) => 0;
uint32_t cycle = 0;
while (true) {
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// chose name, roughly random seed, and random 2^n size
sprintf(path, "roadrunner/test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path,
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
assert(res == 1 || res == LFS_ERR_NOSPC);
if (res == LFS_ERR_NOSPC) {
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
if (err == LFS_ERR_NOSPC) {
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "roadrunner/test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
char r;
lfs_file_read(&lfs, &file, &r, 1) => 1;
assert(r == c);
}
lfs_file_close(&lfs, &file) => 0;
}
lfs_unmount(&lfs) => 0;
cycle += 1;
}
exhausted:
// should still be readable
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "roadrunner/test%d", i);
lfs_stat(&lfs, path, &info) => 0;
}
lfs_unmount(&lfs) => 0;
LFS_WARN("completed %d cycles", cycle);
'''
[[case]] # test running a filesystem to exhaustion
# which also requires expanding superblocks
define.LFS_ERASE_CYCLES = 10
define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
define.LFS_BADBLOCK_BEHAVIOR = [
'LFS_TESTBD_BADBLOCK_PROGERROR',
'LFS_TESTBD_BADBLOCK_ERASEERROR',
'LFS_TESTBD_BADBLOCK_READERROR',
'LFS_TESTBD_BADBLOCK_PROGNOOP',
'LFS_TESTBD_BADBLOCK_ERASENOOP',
]
define.FILES = 10
code = '''
lfs_formatcfg(&lfs, &cfg) => 0;
uint32_t cycle = 0;
while (true) {
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// chose name, roughly random seed, and random 2^n size
sprintf(path, "test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path,
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
assert(res == 1 || res == LFS_ERR_NOSPC);
if (res == LFS_ERR_NOSPC) {
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
if (err == LFS_ERR_NOSPC) {
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
char r;
lfs_file_read(&lfs, &file, &r, 1) => 1;
assert(r == c);
}
lfs_file_close(&lfs, &file) => 0;
}
lfs_unmount(&lfs) => 0;
cycle += 1;
}
exhausted:
// should still be readable
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "test%d", i);
lfs_stat(&lfs, path, &info) => 0;
}
lfs_unmount(&lfs) => 0;
LFS_WARN("completed %d cycles", cycle);
'''
# These are a sort of high-level litmus test for wear-leveling. One definition
# of wear-leveling is that increasing a block device's space translates directly
# into increasing the block devices lifetime. This is something we can actually
# check for.
[[case]] # wear-level test running a filesystem to exhaustion
define.LFS_ERASE_CYCLES = 20
define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
define.FILES = 10
code = '''
uint32_t run_cycles[2];
const uint32_t run_block_count[2] = {LFS_BLOCK_COUNT/2, LFS_BLOCK_COUNT};
for (int run = 0; run < 2; run++) {
for (lfs_block_t b = 0; b < LFS_BLOCK_COUNT; b++) {
lfs_testbd_setwear(&cfg, b,
(b < run_block_count[run]) ? 0 : LFS_ERASE_CYCLES) => 0;
}
lfs_formatcfg(&lfs, &cfg) => 0;
lfs_mountcfg(&lfs, &cfg) => 0;
lfs_mkdir(&lfs, "roadrunner") => 0;
lfs_unmount(&lfs) => 0;
uint32_t cycle = 0;
while (true) {
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// chose name, roughly random seed, and random 2^n size
sprintf(path, "roadrunner/test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path,
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
assert(res == 1 || res == LFS_ERR_NOSPC);
if (res == LFS_ERR_NOSPC) {
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
if (err == LFS_ERR_NOSPC) {
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "roadrunner/test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
char r;
lfs_file_read(&lfs, &file, &r, 1) => 1;
assert(r == c);
}
lfs_file_close(&lfs, &file) => 0;
}
lfs_unmount(&lfs) => 0;
cycle += 1;
}
exhausted:
// should still be readable
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "roadrunner/test%d", i);
lfs_stat(&lfs, path, &info) => 0;
}
lfs_unmount(&lfs) => 0;
run_cycles[run] = cycle;
LFS_WARN("completed %d blocks %d cycles",
run_block_count[run], run_cycles[run]);
}
// check we increased the lifetime by 2x with ~10% error
LFS_ASSERT(run_cycles[1]*110/100 > 2*run_cycles[0]);
'''
[[case]] # wear-level test + expanding superblock
define.LFS_ERASE_CYCLES = 20
define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
define.LFS_BLOCK_CYCLES = 'LFS_ERASE_CYCLES / 2'
define.FILES = 10
code = '''
uint32_t run_cycles[2];
const uint32_t run_block_count[2] = {LFS_BLOCK_COUNT/2, LFS_BLOCK_COUNT};
for (int run = 0; run < 2; run++) {
for (lfs_block_t b = 0; b < LFS_BLOCK_COUNT; b++) {
lfs_testbd_setwear(&cfg, b,
(b < run_block_count[run]) ? 0 : LFS_ERASE_CYCLES) => 0;
}
lfs_formatcfg(&lfs, &cfg) => 0;
uint32_t cycle = 0;
while (true) {
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// chose name, roughly random seed, and random 2^n size
sprintf(path, "test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path,
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
assert(res == 1 || res == LFS_ERR_NOSPC);
if (res == LFS_ERR_NOSPC) {
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
if (err == LFS_ERR_NOSPC) {
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "test%d", i);
srand(cycle * i);
size = 1 << ((rand() % 10)+2);
lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
char r;
lfs_file_read(&lfs, &file, &r, 1) => 1;
assert(r == c);
}
lfs_file_close(&lfs, &file) => 0;
}
lfs_unmount(&lfs) => 0;
cycle += 1;
}
exhausted:
// should still be readable
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "test%d", i);
lfs_stat(&lfs, path, &info) => 0;
}
lfs_unmount(&lfs) => 0;
run_cycles[run] = cycle;
LFS_WARN("completed %d blocks %d cycles",
run_block_count[run], run_cycles[run]);
}
// check we increased the lifetime by 2x with ~10% error
LFS_ASSERT(run_cycles[1]*110/100 > 2*run_cycles[0]);
'''
[[case]] # test that we wear blocks roughly evenly
define.LFS_ERASE_CYCLES = 0xffffffff
define.LFS_BLOCK_COUNT = 256 # small bd so test runs faster
define.LFS_BLOCK_CYCLES = [5, 4, 3, 2, 1]
define.CYCLES = 100
define.FILES = 10
if = 'LFS_BLOCK_CYCLES < CYCLES/10'
code = '''
lfs_formatcfg(&lfs, &cfg) => 0;
lfs_mountcfg(&lfs, &cfg) => 0;
lfs_mkdir(&lfs, "roadrunner") => 0;
lfs_unmount(&lfs) => 0;
uint32_t cycle = 0;
while (cycle < CYCLES) {
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// chose name, roughly random seed, and random 2^n size
sprintf(path, "roadrunner/test%d", i);
srand(cycle * i);
size = 1 << 4; //((rand() % 10)+2);
lfs_file_open(&lfs, &file, path,
LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
lfs_ssize_t res = lfs_file_write(&lfs, &file, &c, 1);
assert(res == 1 || res == LFS_ERR_NOSPC);
if (res == LFS_ERR_NOSPC) {
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
err = lfs_file_close(&lfs, &file);
assert(err == 0 || err == LFS_ERR_NOSPC);
if (err == LFS_ERR_NOSPC) {
lfs_unmount(&lfs) => 0;
goto exhausted;
}
}
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "roadrunner/test%d", i);
srand(cycle * i);
size = 1 << 4; //((rand() % 10)+2);
lfs_file_open(&lfs, &file, path, LFS_O_RDONLY) => 0;
for (lfs_size_t j = 0; j < size; j++) {
char c = 'a' + (rand() % 26);
char r;
lfs_file_read(&lfs, &file, &r, 1) => 1;
assert(r == c);
}
lfs_file_close(&lfs, &file) => 0;
}
lfs_unmount(&lfs) => 0;
cycle += 1;
}
exhausted:
// should still be readable
lfs_mountcfg(&lfs, &cfg) => 0;
for (uint32_t i = 0; i < FILES; i++) {
// check for errors
sprintf(path, "roadrunner/test%d", i);
lfs_stat(&lfs, path, &info) => 0;
}
lfs_unmount(&lfs) => 0;
LFS_WARN("completed %d cycles", cycle);
// check the wear on our block device
lfs_testbd_wear_t minwear = -1;
lfs_testbd_wear_t totalwear = 0;
lfs_testbd_wear_t maxwear = 0;
// skip 0 and 1 as superblock movement is intentionally avoided
for (lfs_block_t b = 2; b < LFS_BLOCK_COUNT; b++) {
lfs_testbd_wear_t wear = lfs_testbd_getwear(&cfg, b);
printf("%08x: wear %d\n", b, wear);
assert(wear >= 0);
if (wear < minwear) {
minwear = wear;
}
if (wear > maxwear) {
maxwear = wear;
}
totalwear += wear;
}
lfs_testbd_wear_t avgwear = totalwear / LFS_BLOCK_COUNT;
LFS_WARN("max wear: %d cycles", maxwear);
LFS_WARN("avg wear: %d cycles", totalwear / LFS_BLOCK_COUNT);
LFS_WARN("min wear: %d cycles", minwear);
// find standard deviation^2
lfs_testbd_wear_t dev2 = 0;
for (lfs_block_t b = 2; b < LFS_BLOCK_COUNT; b++) {
lfs_testbd_wear_t wear = lfs_testbd_getwear(&cfg, b);
assert(wear >= 0);
lfs_testbd_swear_t diff = wear - avgwear;
dev2 += diff*diff;
}
dev2 /= totalwear;
LFS_WARN("std dev^2: %d", dev2);
assert(dev2 < 8);
'''
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