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Implemented lfsr_btree_split, a shortcut for pop+push+push

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Another straightforward exercise of making sure the pending attributes
are setup correctly.

If you think this isn't worth its own function, consider how much
overhead the 3x commits for pop+push+push would add, especially for
large-prog devices.

Worst case this can be dropped in the future.
This commit is contained in:
Christopher Haster
2023-03-13 14:18:22 -05:00
parent dd5af724fd
commit 15e27f92af
2 changed files with 430 additions and 10 deletions
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lfs.c
+68
View File
@@ -4225,6 +4225,74 @@ static int lfsr_btree_pop(lfs_t *lfs, lfsr_btree_t *btree, lfs_size_t id) {
}
}
// lfsr_btree_split can be done with a pop+push+push, but this function
// does all this in one commit, which is much more efficient
static int lfsr_btree_split(lfs_t *lfs, lfsr_btree_t *btree,
lfs_size_t id,
lfsr_tag_t tag1, lfs_size_t weight1,
const void *buffer1, lfs_size_t size1,
lfsr_tag_t tag2, lfs_size_t weight2,
const void *buffer2, lfs_size_t size2) {
LFS_ASSERT(id < btree->weight);
// inlined btree, need to expand into an rbyd
if (btree->tag) {
lfsr_rbyd_t rbyd;
int err = lfsr_rbyd_alloc(lfs, &rbyd, 1);
if (err) {
return err;
}
// commit our entries
err = lfsr_rbyd_commit(lfs, &rbyd,
LFSR_ATTR(GROW, 0, NULL, weight1,
LFSR_ATTR(MKBRANCH, 0+weight1-1, NULL, 0,
LFSR_ATTR_(tag1, 0+weight1-1,
buffer1, size1,
LFSR_ATTR(GROW, weight1, NULL, weight2,
LFSR_ATTR(MKBRANCH, weight1+weight2-1, NULL, 0,
LFSR_ATTR_(tag2, weight1+weight2-1,
buffer2, size2,
NULL)))))));
if (err) {
return err;
}
btree->tag = 0;
btree->weight = rbyd.weight;
btree->u.trunk.block = rbyd.block;
btree->u.trunk.limit = rbyd.off;
return 0;
// a normal btree
} else {
// lookup in which leaf our id resides
lfsr_rbyd_t rbyd;
lfs_ssize_t rid;
lfs_size_t rweight;
lfs_ssize_t size = lfsr_btree_lookup(lfs, btree, id,
NULL, NULL, &rbyd, &rid, &rweight, NULL, 0);
if (size < 0) {
return size;
}
// commit our id into the tree, letting lfsr_btree_commit take care
// of the rest
return lfsr_btree_commit(lfs, btree, id, &rbyd,
LFSR_ATTR(SHRINK, rid-(rweight-1), NULL, rweight,
LFSR_ATTR(GROW, rid-(rweight-1), NULL, weight1,
LFSR_ATTR(MKBRANCH, rid-(rweight-1)+weight1-1, NULL, 0,
LFSR_ATTR_(tag1, rid-(rweight-1)+weight1-1,
buffer1, size1,
LFSR_ATTR(GROW, rid-(rweight-1)+weight1, NULL, weight2,
LFSR_ATTR(MKBRANCH, rid-(rweight-1)+weight1+weight2-1, NULL, 0,
LFSR_ATTR_(tag2, rid-(rweight-1)+weight1+weight2-1,
buffer2, size2,
NULL))))))));
}
}
tests/test_btree.toml
+362 -10
View File
@@ -457,7 +457,7 @@ code = '''
// check that btree matches sim
printf("expd: [");
bool first = true;
for (lfs_size_t i = 0; i < N; i++) {
for (lfs_size_t i = 0; i < sim_size; i++) {
if (!first) {
printf(", ");
}
@@ -470,13 +470,13 @@ code = '''
btree.u.trunk.limit,
btree.tag,
btree.weight);
assert(btree.weight == N);
assert(btree.weight == sim_size);
uint8_t buffer[4];
lfsr_tag_t tag_;
lfs_size_t id_;
lfs_size_t weight_;
for (lfs_size_t i = 0; i < N; i++) {
for (lfs_size_t i = 0; i < sim_size; i++) {
lfsr_btree_get(&lfs, &btree, i,
&tag_, &id_, &weight_,
buffer, 4) => 1;
@@ -487,7 +487,7 @@ code = '''
}
// and no extra elements
lfsr_btree_get(&lfs, &btree, N,
lfsr_btree_get(&lfs, &btree, sim_size,
&tag_, &id_, &weight_,
buffer, 4) => LFS_ERR_NOENT;
@@ -627,7 +627,7 @@ code = '''
// check that btree matches sim
printf("expd: [");
bool first = true;
for (lfs_size_t i = 0; i < N; i++) {
for (lfs_size_t i = 0; i < sim_size; i++) {
// calculate actual id in btree space
lfs_size_t weighted_id = 0;
for (lfs_size_t j = 0; j < i; j++) {
@@ -649,7 +649,7 @@ code = '''
btree.weight);
lfs_size_t total_weight = 0;
for (lfs_size_t j = 0; j < N; j++) {
for (lfs_size_t j = 0; j < sim_size; j++) {
total_weight += sim_weights[j];
}
assert(btree.weight == total_weight);
@@ -658,7 +658,7 @@ code = '''
lfsr_tag_t tag_;
lfs_size_t id_;
lfs_size_t weight_;
for (lfs_size_t i = 0; i < N; i++) {
for (lfs_size_t i = 0; i < sim_size; i++) {
// calculate actual id in btree space
lfs_size_t weighted_id = 0;
for (lfs_size_t j = 0; j < i; j++) {
@@ -681,7 +681,7 @@ code = '''
// also test that we can traverse the tree without prior knowledge
id_ = -1;
for (lfs_size_t i = 0; i < N; i++) {
for (lfs_size_t i = 0; i < sim_size; i++) {
// calculate actual id in btree space
lfs_size_t weighted_id = 0;
for (lfs_size_t j = 0; j < i; j++) {
@@ -2068,8 +2068,360 @@ code = '''
'''
# TODO [cases.test_btree_split]
# TODO [cases.test_btree_split_fuzz]
# test btree splits
[cases.test_btree_split]
defines.N = [4, 8, 16, 32, 64, 128, 256, 512, 1024]
in = 'lfs.c'
code = '''
lfs_t lfs;
lfs_init(&lfs, cfg) => 0;
// create free lookahead
memset(lfs.free.buffer, 0, lfs.cfg->lookahead_size);
lfs.free.off = 0;
lfs.free.size = lfs_min(8*lfs.cfg->lookahead_size,
lfs.cfg->block_count);
lfs.free.i = 0;
lfs_alloc_ack(&lfs);
// create a tree with N elements
lfsr_btree_t btree = LFSR_BTREE_NULL;
const char *alphas = "abcdefghijklmnopqrstuvwxyz";
lfsr_btree_push(&lfs, &btree, 0, LFSR_TAG_INLINED, 1,
&alphas[0 % 26], 1) => 0;
for (lfs_size_t i = 1; i < N; i++) {
lfsr_btree_split(&lfs, &btree, i-1,
LFSR_TAG_INLINED, 1, &alphas[(i-1) % 26], 1,
LFSR_TAG_INLINED, 1, &alphas[(i-0) % 26], 1) => 0;
}
printf("btree: 0x%x.%x 0x%x w%d\n",
btree.u.trunk.block,
btree.u.trunk.limit,
btree.tag,
btree.weight);
assert(btree.weight == N);
// check that the elements are in the tree
uint8_t buffer[4];
lfsr_tag_t tag_;
lfs_size_t id_;
lfs_size_t weight_;
for (lfs_size_t i = 0; i < N; i++) {
lfsr_btree_get(&lfs, &btree, i,
&tag_, &id_, &weight_,
buffer, 4) => 1;
assert(tag_ == LFSR_TAG_INLINED);
assert(id_ == i);
assert(weight_ == 1);
assert(memcmp(buffer, &alphas[i % 26], 1) == 0);
}
// and check that we can't lookup elements that aren't in the tree
lfsr_btree_get(&lfs, &btree, N,
&tag_, &id_, &weight_,
buffer, 4) => LFS_ERR_NOENT;
'''
[cases.test_btree_split_fuzz]
defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
defines.ITER = 10
in = 'lfs.c'
code = '''
const char *alphas = "abcdefghijklmnopqrstuvwxyz";
const char *uppers = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
// iterate through severals seeds that we can reproduce easily
for (uint32_t seed = 1; seed < ITER+1; seed++) {
// create lfs here since we need to reset each iteration, we're
// space constrained and we can't expect gc to work at this point
lfs_t lfs;
lfs_init(&lfs, cfg) => 0;
// create free lookahead
memset(lfs.free.buffer, 0, lfs.cfg->lookahead_size);
lfs.free.off = 0;
lfs.free.size = lfs_min(8*lfs.cfg->lookahead_size,
lfs.cfg->block_count);
lfs.free.i = 0;
lfs_alloc_ack(&lfs);
// create a btree
lfsr_btree_t btree = LFSR_BTREE_NULL;
lfsr_btree_push(&lfs, &btree, 0, LFSR_TAG_INLINED, 1,
&alphas[0 % 26], 1) => 0;
// set up a simulation to compare against
//
// fun fact this is slower than our actual tree! unfun fact this is
// starting to be a problem...
char *sim = malloc(N);
lfs_size_t sim_size = 1;
memset(sim, 0, N);
sim[0] = alphas[0 % 26];
uint32_t prng = seed;
for (lfs_size_t i = 1; i < N; i++) {
// choose a pseudo-random id
lfs_size_t id = TEST_PRNG(&prng) % sim_size;
// split btree
lfsr_btree_split(&lfs, &btree, id,
LFSR_TAG_INLINED, 1, &alphas[i % 26], 1,
LFSR_TAG_INLINED, 1, &uppers[i % 26], 1) => 0;
// split sim
memmove(&sim[id+1], &sim[id], sim_size-id);
sim[id+0] = alphas[i % 26];
sim[id+1] = uppers[i % 26];
sim_size += 1;
}
// check that btree matches sim
printf("expd: [");
bool first = true;
for (lfs_size_t i = 0; i < sim_size; i++) {
if (!first) {
printf(", ");
}
first = false;
printf("%c", sim[i]);
}
printf("]\n");
printf("btree: 0x%x.%x 0x%x w%d\n",
btree.u.trunk.block,
btree.u.trunk.limit,
btree.tag,
btree.weight);
assert(btree.weight == sim_size);
uint8_t buffer[4];
lfsr_tag_t tag_;
lfs_size_t id_;
lfs_size_t weight_;
for (lfs_size_t i = 0; i < sim_size; i++) {
lfsr_btree_get(&lfs, &btree, i,
&tag_, &id_, &weight_,
buffer, 4) => 1;
assert(tag_ == LFSR_TAG_INLINED);
assert(id_ == i);
assert(weight_ == 1);
assert(memcmp(buffer, &sim[i], 1) == 0);
}
// and no extra elements
lfsr_btree_get(&lfs, &btree, sim_size,
&tag_, &id_, &weight_,
buffer, 4) => LFS_ERR_NOENT;
// clean up sim
free(sim);
lfs_deinit(&lfs) => 0;
}
'''
[cases.test_btree_split_sparse]
defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024]
defines.W = 5
in = 'lfs.c'
code = '''
lfs_t lfs;
lfs_init(&lfs, cfg) => 0;
// create free lookahead
memset(lfs.free.buffer, 0, lfs.cfg->lookahead_size);
lfs.free.off = 0;
lfs.free.size = lfs_min(8*lfs.cfg->lookahead_size,
lfs.cfg->block_count);
lfs.free.i = 0;
lfs_alloc_ack(&lfs);
// create a tree with N elements
lfsr_btree_t btree = LFSR_BTREE_NULL;
const char *alphas = "abcdefghijklmnopqrstuvwxyz";
lfsr_btree_push(&lfs, &btree, 0, LFSR_TAG_INLINED, W,
&alphas[0 % 26], 1) => 0;
for (lfs_size_t i = 1; i < N; i++) {
lfsr_btree_split(&lfs, &btree, (i-1)*W+W-1,
LFSR_TAG_INLINED, W, &alphas[(i-1) % 26], 1,
LFSR_TAG_INLINED, W, &alphas[(i-0) % 26], 1) => 0;
}
printf("btree: 0x%x.%x 0x%x w%d\n",
btree.u.trunk.block,
btree.u.trunk.limit,
btree.tag,
btree.weight);
assert(btree.weight == N*W);
// check that the elements are in the tree
uint8_t buffer[4];
lfsr_tag_t tag_;
lfs_size_t id_;
lfs_size_t weight_;
for (lfs_size_t i = 0; i < N; i++) {
lfsr_btree_get(&lfs, &btree, i*W+W-1,
&tag_, &id_, &weight_,
buffer, 4) => 1;
assert(tag_ == LFSR_TAG_INLINED);
assert(id_ == i*W+W-1);
assert(weight_ == W);
assert(memcmp(buffer, &alphas[i % 26], 1) == 0);
}
// and check that we can't lookup elements that aren't in the tree
lfsr_btree_get(&lfs, &btree, N*W,
&tag_, &id_, &weight_,
buffer, 4) => LFS_ERR_NOENT;
'''
[cases.test_btree_split_sparse_fuzz]
defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
defines.W = 5
defines.ITER = 10
in = 'lfs.c'
code = '''
const char *alphas = "abcdefghijklmnopqrstuvwxyz";
const char *uppers = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
// iterate through severals seeds that we can reproduce easily
for (uint32_t seed = 1; seed < ITER+1; seed++) {
// create lfs here since we need to reset each iteration, we're
// space constrained and we can't expect gc to work at this point
lfs_t lfs;
lfs_init(&lfs, cfg) => 0;
// create free lookahead
memset(lfs.free.buffer, 0, lfs.cfg->lookahead_size);
lfs.free.off = 0;
lfs.free.size = lfs_min(8*lfs.cfg->lookahead_size,
lfs.cfg->block_count);
lfs.free.i = 0;
lfs_alloc_ack(&lfs);
// create a btree
lfsr_btree_t btree = LFSR_BTREE_NULL;
lfsr_btree_push(&lfs, &btree, 0, LFSR_TAG_INLINED, W,
&alphas[0 % 26], 1) => 0;
// set up a simulation to compare against
//
// fun fact this is slower than our actual tree! unfun fact this is
// starting to be a problem...
char *sim = malloc(N);
lfs_size_t *sim_weights = malloc(N*sizeof(lfs_size_t));
lfs_size_t sim_size = 1;
memset(sim, 0, N);
memset(sim_weights, 0, N*sizeof(lfs_size_t));
sim[0] = alphas[0 % 26];
sim_weights[0] = W;
uint32_t prng = seed;
for (lfs_size_t i = 1; i < N; i++) {
// choose a pseudo-random id
lfs_size_t id = TEST_PRNG(&prng) % sim_size;
// choose pseudo-random weights
lfs_size_t weight1 = 1 + (TEST_PRNG(&prng) % W);
lfs_size_t weight2 = 1 + (TEST_PRNG(&prng) % W);
// calculate actual id in btree space
lfs_size_t weighted_id = 0;
for (lfs_size_t j = 0; j < id; j++) {
weighted_id += sim_weights[j];
}
// split btree
lfsr_btree_split(&lfs, &btree, weighted_id+sim_weights[id]-1,
LFSR_TAG_INLINED, weight1, &alphas[i % 26], 1,
LFSR_TAG_INLINED, weight2, &uppers[i % 26], 1) => 0;
// add to sim
memmove(&sim[id+1], &sim[id], sim_size-id);
memmove(&sim_weights[id+1], &sim_weights[id],
(sim_size-id)*sizeof(lfs_size_t));
sim[id+0] = alphas[i % 26];
sim[id+1] = uppers[i % 26];
sim_weights[id+0] = weight1;
sim_weights[id+1] = weight2;
sim_size += 1;
}
// check that btree matches sim
printf("expd: [");
bool first = true;
for (lfs_size_t i = 0; i < sim_size; i++) {
// calculate actual id in btree space
lfs_size_t weighted_id = 0;
for (lfs_size_t j = 0; j < i; j++) {
weighted_id += sim_weights[j];
}
if (!first) {
printf(", ");
}
first = false;
printf("%dw%d=%c", weighted_id+sim_weights[i]-1,
sim_weights[i], sim[i]);
}
printf("]\n");
printf("btree: 0x%x.%x 0x%x w%d\n",
btree.u.trunk.block,
btree.u.trunk.limit,
btree.tag,
btree.weight);
lfs_size_t total_weight = 0;
for (lfs_size_t j = 0; j < N; j++) {
total_weight += sim_weights[j];
}
assert(btree.weight == total_weight);
uint8_t buffer[4];
lfsr_tag_t tag_;
lfs_size_t id_;
lfs_size_t weight_;
for (lfs_size_t i = 0; i < N; i++) {
// calculate actual id in btree space
lfs_size_t weighted_id = 0;
for (lfs_size_t j = 0; j < i; j++) {
weighted_id += sim_weights[j];
}
lfsr_btree_get(&lfs, &btree, weighted_id+sim_weights[i]-1,
&tag_, &id_, &weight_,
buffer, 4) => 1;
assert(tag_ == LFSR_TAG_INLINED);
assert(id_ == weighted_id+sim_weights[i]-1);
assert(weight_ == sim_weights[i]);
assert(memcmp(buffer, &sim[i], 1) == 0);
}
// and no extra elements
lfsr_btree_get(&lfs, &btree, total_weight,
&tag_, &id_, &weight_,
buffer, 4) => LFS_ERR_NOENT;
// also test that we can traverse the tree without prior knowledge
id_ = -1;
for (lfs_size_t i = 0; i < N; i++) {
// calculate actual id in btree space
lfs_size_t weighted_id = 0;
for (lfs_size_t j = 0; j < i; j++) {
weighted_id += sim_weights[j];
}
lfsr_btree_get(&lfs, &btree, id_+1,
&tag_, &id_, &weight_,
buffer, 4) => 1;
assert(tag_ == LFSR_TAG_INLINED);
assert(id_ == weighted_id+sim_weights[i]-1);
assert(weight_ == sim_weights[i]);
assert(memcmp(buffer, &sim[i], 1) == 0);
}
lfsr_btree_get(&lfs, &btree, id_+1,
&tag_, &id_, &weight_,
buffer, 4) => LFS_ERR_NOENT;
// clean up sim
free(sim);
}
'''