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Tweaked mid to use sign-bit to indicate mroots

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This is an intermediate commit as a part of a tangent into compressed
mids.

The idea here, is instead of using bid=-1 as a special value for mroots,
use only the top bit to indicate mroots. This allows you to compare
against the grm/other uninlined mids by masking instead of signed
comparison.

This is valuable for compressed mids since extracting bids relies on
knowledge of the block size, and becomes quite a bit more expensive.

            mroot bid                             mroot cmp
  before:  0xffffffff  lfs_smax32(a, 0) == lfs_smax32(b, 0)
  after:   0x80000000  (a & 0x7fffffff) == (b & 0x7fffffff)

The implementation here is a bit clumsy. I think GCC may be not that
great at optimizing out copies of structs being passed around via
inlined functions. But this is only a proof-of-concept.
This commit is contained in:
Christopher Haster
2023-08-24 15:27:05 -05:00
parent ff87aa41f2
commit 9f18b1fd50
4 changed files with 169 additions and 163 deletions
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tests/test_mtree.toml
+68 -74
View File
@@ -417,7 +417,7 @@ code = '''
// create entries
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(lfsr_mtree_weight(&lfs)-1, -1),
lfsr_mtree_lookup(&lfs, LFSR_MID(lfs_smax32(lfsr_mtree_weight(&lfs)-1, 0), -1),
&mdir) => 0;
mdir.mid.rid = 0;
@@ -442,8 +442,8 @@ code = '''
// try looking up each entry
lfs_size_t i = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -467,8 +467,8 @@ code = '''
// try looking up each entry
i = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -510,9 +510,8 @@ code = '''
uint32_t prng = SEED;
for (lfs_size_t i = 0; i < N; i++) {
// choose a pseudo-random mid
lfs_ssize_t mid = lfsr_mtree_weight(&lfs) == 0
? -1
: (lfs_ssize_t)(TEST_PRNG(&prng) % lfsr_mtree_weight(&lfs));
lfs_ssize_t mid = (lfs_ssize_t)(
TEST_PRNG(&prng) % lfs_max32(lfsr_mtree_weight(&lfs), 1));
// fetch mdir
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -542,8 +541,8 @@ code = '''
// try looking up each entry
lfs_size_t count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -571,8 +570,8 @@ code = '''
// try looking up each entry
count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -1267,7 +1266,7 @@ code = '''
// create entries
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(lfsr_mtree_weight(&lfs)-1, -1),
lfsr_mtree_lookup(&lfs, LFSR_MID(lfs_smax32(lfsr_mtree_weight(&lfs)-1, 0), -1),
&mdir) => 0;
mdir.mid.rid = 0;
@@ -1286,12 +1285,11 @@ code = '''
// remove entries
for (lfs_size_t i = 0; i < N - REMAINING; i++) {
lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
lfsr_mtree_lookup(&lfs, LFSR_MID(0, -1), &mdir) => 0;
// drop should make sure we never have empty mdirs
assert(mdir.mid.bid == -1 || mdir.u.m.weight > 0);
assert(lfsr_mdir_ismroot(&mdir) || mdir.u.m.weight > 0);
// force a compaction?
if (FORCE_COMPACTION) {
@@ -1305,8 +1303,8 @@ code = '''
// try looking up each entry
lfs_size_t i = N - REMAINING;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -1330,8 +1328,8 @@ code = '''
// try looking up each entry
i = N - REMAINING;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -1369,7 +1367,7 @@ code = '''
for (lfs_size_t cycle = 0; cycle < CYCLES; cycle++) {
// create entries
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(lfsr_mtree_weight(&lfs)-1, -1),
lfsr_mtree_lookup(&lfs, LFSR_MID(lfs_smax32(lfsr_mtree_weight(&lfs)-1, 0), -1),
&mdir) => 0;
mdir.mid.rid = 0;
@@ -1388,8 +1386,8 @@ code = '''
// try looking up each entry
lfs_size_t i = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -1407,12 +1405,11 @@ code = '''
// remove entries
for (lfs_size_t i = 0; i < N; i++) {
lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
lfsr_mtree_lookup(&lfs, LFSR_MID(0, -1), &mdir) => 0;
// drop should make sure we never have empty mdirs
assert(mdir.mid.bid == -1 || mdir.u.m.weight > 0);
assert(lfsr_mdir_ismroot(&mdir) || mdir.u.m.weight > 0);
// force a compaction?
if (FORCE_COMPACTION) {
@@ -1462,9 +1459,8 @@ code = '''
uint32_t prng = SEED;
for (lfs_size_t i = 0; i < N; i++) {
// choose a pseudo-random mid
lfs_ssize_t mid = lfsr_mtree_weight(&lfs) == 0
? -1
: (lfs_ssize_t)(TEST_PRNG(&prng) % lfsr_mtree_weight(&lfs));
lfs_ssize_t mid = (lfs_ssize_t)(
TEST_PRNG(&prng) % lfs_max32(lfsr_mtree_weight(&lfs), 1));
// fetch mdir
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -1508,14 +1504,14 @@ code = '''
// try looking up each entry
lfs_size_t count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
// drop should make sure we never have empty mdirs
assert(mdir.mid.bid == -1 || mdir.u.m.weight > 0);
assert(lfsr_mdir_ismroot(&mdir) || mdir.u.m.weight > 0);
for (mdir.mid.rid = 0;
mdir.mid.rid < (lfs_ssize_t)mdir.u.m.weight;
@@ -1541,14 +1537,14 @@ code = '''
// try looking up each entry
count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
// drop should make sure we never have empty mdirs
assert(mdir.mid.bid == -1 || mdir.u.m.weight > 0);
assert(lfsr_mdir_ismroot(&mdir) || mdir.u.m.weight > 0);
for (mdir.mid.rid = 0;
mdir.mid.rid < (lfs_ssize_t)mdir.u.m.weight;
@@ -2539,9 +2535,8 @@ code = '''
uint32_t prng = SEED;
for (lfs_size_t i = 0; i < N; i++) {
// choose a pseudo-random mid
lfs_ssize_t mid = lfsr_mtree_weight(&lfs) == 0
? -1
: (lfs_ssize_t)(TEST_PRNG(&prng) % lfsr_mtree_weight(&lfs));
lfs_ssize_t mid = (lfs_ssize_t)(
TEST_PRNG(&prng) % lfs_max32(lfsr_mtree_weight(&lfs), 1));
// fetch mdir
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -2598,14 +2593,14 @@ code = '''
// try looking up each entry
lfs_size_t count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
// drop should make sure we never have empty mdirs
assert(mdir.mid.bid == -1 || mdir.u.m.weight > 0);
assert(lfsr_mdir_ismroot(&mdir) || mdir.u.m.weight > 0);
for (mdir.mid.rid = 0;
mdir.mid.rid < (lfs_ssize_t)mdir.u.m.weight;
@@ -2631,14 +2626,14 @@ code = '''
// try looking up each entry
count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
// drop should make sure we never have empty mdirs
assert(mdir.mid.bid == -1 || mdir.u.m.weight > 0);
assert(lfsr_mdir_ismroot(&mdir) || mdir.u.m.weight > 0);
for (mdir.mid.rid = 0;
mdir.mid.rid < (lfs_ssize_t)mdir.u.m.weight;
@@ -2680,9 +2675,9 @@ code = '''
assert(lfsr_mtree_isinlined(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=LFSR_MID(-1, 0), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 0), .u=lfs.mroot.u}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=LFSR_MID(-1, 1), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 1), .u=lfs.mroot.u}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &right_neighbor);
@@ -2700,12 +2695,12 @@ code = '''
// assert that our neighbors were updated correctly
assert(!lfsr_mdir_isdropped(&left_neighbor.mdir));
assert(left_neighbor.mdir.mid.bid == -1);
assert(left_neighbor.mdir.mid.bid == lfs.mroot.mid.bid);
assert(left_neighbor.mdir.mid.rid == 0);
assert(memcmp(&left_neighbor.mdir.u, &lfs.mroot.u,
sizeof(lfs.mroot.u)) == 0);
assert(!lfsr_mdir_isdropped(&right_neighbor.mdir));
assert(right_neighbor.mdir.mid.bid == -1);
assert(right_neighbor.mdir.mid.bid == lfs.mroot.mid.bid);
assert(right_neighbor.mdir.mid.rid == 2);
assert(memcmp(&right_neighbor.mdir.u, &lfs.mroot.u,
sizeof(lfs.mroot.u)) == 0);
@@ -2734,9 +2729,9 @@ code = '''
assert(lfsr_mtree_isinlined(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=LFSR_MID(-1, 0), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 0), .u=lfs.mroot.u}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=LFSR_MID(-1, 1), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 1), .u=lfs.mroot.u}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &right_neighbor);
@@ -2750,7 +2745,7 @@ code = '''
// assert that our neighbors were updated correctly
assert(lfsr_mdir_isdropped(&left_neighbor.mdir));
assert(!lfsr_mdir_isdropped(&right_neighbor.mdir));
assert(right_neighbor.mdir.mid.bid == -1);
assert(right_neighbor.mdir.mid.bid == lfs.mroot.mid.bid);
assert(right_neighbor.mdir.mid.rid == 0);
assert(memcmp(&right_neighbor.mdir.u, &lfs.mroot.u,
sizeof(lfs.mroot.u)) == 0);
@@ -2779,9 +2774,9 @@ code = '''
assert(lfsr_mtree_isinlined(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=LFSR_MID(-1, 0), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 0), .u=lfs.mroot.u}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=LFSR_MID(-1, 1), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 1), .u=lfs.mroot.u}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &right_neighbor);
@@ -2794,7 +2789,7 @@ code = '''
// assert that our neighbors were updated correctly
assert(!lfsr_mdir_isdropped(&left_neighbor.mdir));
assert(left_neighbor.mdir.mid.bid == -1);
assert(left_neighbor.mdir.mid.bid == lfs.mroot.mid.bid);
assert(left_neighbor.mdir.mid.rid == 0);
assert(memcmp(&left_neighbor.mdir.u, &lfs.mroot.u,
sizeof(lfs.mroot.u)) == 0);
@@ -2826,9 +2821,9 @@ code = '''
assert(lfsr_mtree_isinlined(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=LFSR_MID(-1, 0), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 0), .u=lfs.mroot.u}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=LFSR_MID(-1, 1), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 1), .u=lfs.mroot.u}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &right_neighbor);
@@ -2909,9 +2904,9 @@ code = '''
assert(lfsr_mtree_isinlined(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=LFSR_MID(-1, 0), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 0), .u=lfs.mroot.u}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=LFSR_MID(-1, 1), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 1), .u=lfs.mroot.u}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &right_neighbor);
@@ -3093,9 +3088,9 @@ code = '''
assert(lfsr_mtree_isinlined(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=LFSR_MID(-1, 0), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 0), .u=lfs.mroot.u}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=LFSR_MID(-1, 1), .u=lfs.mroot.u}};
.mdir={.mid=LFSR_MID(lfs.mroot.mid.bid, 1), .u=lfs.mroot.u}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_REG, &right_neighbor);
@@ -3125,12 +3120,12 @@ code = '''
// assert that our neighbors were updated correctly
assert(!lfsr_mdir_isdropped(&left_neighbor.mdir));
assert(left_neighbor.mdir.mid.bid == -1);
assert(left_neighbor.mdir.mid.bid == lfs.mroot.mid.bid);
assert(left_neighbor.mdir.mid.rid == 0);
assert(memcmp(&left_neighbor.mdir.u, &lfs.mroot.u,
sizeof(lfs.mroot.u)) == 0);
assert(!lfsr_mdir_isdropped(&right_neighbor.mdir));
assert(right_neighbor.mdir.mid.bid == -1);
assert(right_neighbor.mdir.mid.bid == lfs.mroot.mid.bid);
assert(right_neighbor.mdir.mid.rid == 1);
assert(memcmp(&right_neighbor.mdir.u, &lfs.mroot.u,
sizeof(lfs.mroot.u)) == 0);
@@ -3934,7 +3929,7 @@ code = '''
// create entries
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(lfsr_mtree_weight(&lfs)-1, -1),
lfsr_mtree_lookup(&lfs, LFSR_MID(lfs_smax32(lfsr_mtree_weight(&lfs)-1, 0), -1),
&mdir) => 0;
mdir.mid.rid = 0;
@@ -3959,8 +3954,8 @@ code = '''
// try looking up each entry
lfs_size_t i = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -4044,8 +4039,8 @@ code = '''
// try looking up each entry
i = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -4087,9 +4082,8 @@ code = '''
uint32_t prng = SEED;
for (lfs_size_t i = 0; i < N; i++) {
// choose a pseudo-random mid
lfs_ssize_t mid = lfsr_mtree_weight(&lfs) == 0
? -1
: (lfs_ssize_t)(TEST_PRNG(&prng) % lfsr_mtree_weight(&lfs));
lfs_ssize_t mid = (lfs_ssize_t)(
TEST_PRNG(&prng) % lfs_max32(lfsr_mtree_weight(&lfs), 1));
// fetch mdir
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -4119,8 +4113,8 @@ code = '''
// try looking up each entry
lfs_size_t count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;
@@ -4209,8 +4203,8 @@ code = '''
// try looking up each entry
count_ = 0;
for (lfs_ssize_t mid = (lfsr_mtree_isinlined(&lfs) ? -1 : 0);
mid < (lfs_ssize_t)lfsr_mtree_weight(&lfs);
for (lfs_ssize_t mid = 0;
mid < lfs_smax32(lfsr_mtree_weight(&lfs), 1);
mid++) {
lfsr_mdir_t mdir;
lfsr_mtree_lookup(&lfs, LFSR_MID(mid, -1), &mdir) => 0;