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Changed becksum lookup to not re-traverse the whole btree

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We already get the leaf rbyd as a part of btree lookup, and since ids
can't be split across rbyd boundaries, we can be sure any bptr attrs
live in the same rbyd.

This can be extended to any future bptr attrs.

Aside from the small performance gain, this also means we can drop the
btree bid+tag lookups. All extra attr lookups to lookup the rbyd first.
This saves a bit of code but also avoids a set of issues with the btree
semantics where lookupnexting an extra attr can return ENOENT
prematurely when on an rbyd boundary.

As I'm typing this I realize this means we have no way to iterate over
all _tags_ in a btree, only over all _bids_. Fortunately I don't think
we will ever need the former.

            code          stack
  before:  32136           2880
  after:   31956 (-0.6%)   2880 (+0.0%)
This commit is contained in:
Christopher Haster
2023-12-14 11:55:23 -06:00
parent 34b1e3ef00
commit 3e45fc739d
2 changed files with 52 additions and 71 deletions
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tests/test_btree.toml
+21 -21
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@@ -15,7 +15,7 @@ code = '''
lfsr_tag_t *tag_, lfs_size_t *weight_,
void *buffer, lfs_size_t size) {
lfsr_data_t data;
int err = lfsr_btree_lookup(lfs, btree, bid, LFSR_TAG_STRUCT,
int err = lfsr_btree_lookup(lfs, btree, bid,
tag_, weight_, &data);
if (err) {
return err;
@@ -40,7 +40,7 @@ code = '''
// lookup weight to compute deltas
lfs_size_t weight_;
int err = lfsr_btree_lookupnext(lfs, btree, bid, LFSR_TAG_STRUCT,
int err = lfsr_btree_lookupnext(lfs, btree, bid,
NULL, NULL, &weight_, NULL);
if (err) {
return err;
@@ -60,7 +60,7 @@ code = '''
// lookup weight to compute deltas
lfs_size_t weight_;
int err = lfsr_btree_lookupnext(lfs, btree, bid, LFSR_TAG_STRUCT,
int err = lfsr_btree_lookupnext(lfs, btree, bid,
NULL, NULL, &weight_, NULL);
if (err) {
return err;
@@ -79,7 +79,7 @@ code = '''
// lookup weight to compute deltas
lfs_size_t weight_;
int err = lfsr_btree_lookupnext(lfs, btree, bid, LFSR_TAG_STRUCT,
int err = lfsr_btree_lookupnext(lfs, btree, bid,
NULL, NULL, &weight_, NULL);
if (err) {
return err;
@@ -630,7 +630,7 @@ code = '''
lfs_size_t bid_ = -1;
lfsr_data_t data_;
for (lfs_size_t i = 0; i < n; i++) {
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == i*W+W-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -639,7 +639,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, &alphas[i % 26], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
'''
@@ -767,7 +767,7 @@ code = '''
weighted_bid += sim_weights[j];
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == weighted_bid+sim_weights[i]-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -776,7 +776,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, &sim[i], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
// clean up sim
@@ -1186,7 +1186,7 @@ code = '''
lfs_size_t bid_ = -1;
lfsr_data_t data_;
for (lfs_size_t i = 0; i < N; i++) {
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == i*W+W-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -1195,7 +1195,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, &uppers[i % 26], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
'''
@@ -1334,7 +1334,7 @@ code = '''
weighted_bid += sim_weights[j];
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == weighted_bid+sim_weights[i]-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -1343,7 +1343,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, &sim[i], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
// clean up sim
@@ -2005,7 +2005,7 @@ code = '''
lfs_size_t bid_ = -1;
lfsr_data_t data_;
for (lfs_size_t i = 0; i < REMAINING; i++) {
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == i*W+W-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -2015,7 +2015,7 @@ code = '''
assert(memcmp(buffer, &alphas[i % 26], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == REMAINING*W+W-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -2024,7 +2024,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "R", 1) == 0);
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
'''
@@ -2176,7 +2176,7 @@ code = '''
weighted_bid += sim_weights[j];
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == weighted_bid+sim_weights[i]-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -2185,7 +2185,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, &sim[i], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
// clean up sim
@@ -2558,7 +2558,7 @@ code = '''
weighted_bid += sim_weights[j];
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == weighted_bid+sim_weights[i]-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -2567,7 +2567,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, &sim[i], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
// clean up sim
@@ -3114,7 +3114,7 @@ code = '''
weighted_bid += sim_weights[j];
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => 0;
assert(bid_ == weighted_bid+sim_weights[i]-1);
assert(tag_ == LFSR_TAG_DATA);
@@ -3123,7 +3123,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, &sim[i], 1) == 0);
}
lfsr_btree_lookupnext(&lfs, &btree, bid_+1, LFSR_TAG_STRUCT,
lfsr_btree_lookupnext(&lfs, &btree, bid_+1,
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
// clean up sim