coalesce tombstones in map insert

This commit is contained in:
jason
2023-07-21 15:44:39 -04:00
parent 1b3657122c
commit f9c083073e

View File

@@ -414,68 +414,21 @@ map_insert_hash_dynamic :: proc "odin" (#no_alias m: ^Raw_Map, #no_alias info: ^
tk := map_cell_index_dynamic(sk, info.ks, 1)
tv := map_cell_index_dynamic(sv, info.vs, 1)
for {
hp := &hs[pos]
element_hash := hp^
swap_loop: for {
element_hash := hs[pos]
if map_hash_is_empty(element_hash) {
kp := map_cell_index_dynamic(ks, info.ks, pos)
vp := map_cell_index_dynamic(vs, info.vs, pos)
intrinsics.mem_copy_non_overlapping(rawptr(kp), rawptr(k), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(vp), rawptr(v), size_of_v)
hp^ = h
k_dst := map_cell_index_dynamic(ks, info.ks, pos)
v_dst := map_cell_index_dynamic(vs, info.vs, pos)
intrinsics.mem_copy_non_overlapping(rawptr(k_dst), rawptr(k), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v_dst), rawptr(v), size_of_v)
hs[pos] = h
return result if result != 0 else vp
return result if result != 0 else v_dst
}
if map_hash_is_deleted(element_hash) {
next_pos := (pos + 1) & mask
// backward shift
for !map_hash_is_empty(hs[next_pos]) {
probe_distance := map_probe_distance(m^, hs[next_pos], next_pos)
if probe_distance == 0 {
break
}
probe_distance -= 1
kp := map_cell_index_dynamic(ks, info.ks, pos)
vp := map_cell_index_dynamic(vs, info.vs, pos)
kn := map_cell_index_dynamic(ks, info.ks, next_pos)
vn := map_cell_index_dynamic(vs, info.vs, next_pos)
if distance > probe_distance {
if result == 0 {
result = vp
}
// move stored into pos; store next
intrinsics.mem_copy_non_overlapping(rawptr(kp), rawptr(k), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(vp), rawptr(v), size_of_v)
hs[pos] = h
intrinsics.mem_copy_non_overlapping(rawptr(k), rawptr(kn), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v), rawptr(vn), size_of_v)
h = hs[next_pos]
} else {
// move next back 1
intrinsics.mem_copy_non_overlapping(rawptr(kp), rawptr(kn), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(vp), rawptr(vn), size_of_v)
hs[pos] = hs[next_pos]
distance = probe_distance
}
hs[next_pos] = 0
pos = (pos + 1) & mask
next_pos = (next_pos + 1) & mask
distance += 1
}
kp := map_cell_index_dynamic(ks, info.ks, pos)
vp := map_cell_index_dynamic(vs, info.vs, pos)
intrinsics.mem_copy_non_overlapping(rawptr(kp), rawptr(k), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(vp), rawptr(v), size_of_v)
hs[pos] = h
return result if result != 0 else vp
break swap_loop
}
if probe_distance := map_probe_distance(m^, element_hash, pos); distance > probe_distance {
@@ -495,8 +448,8 @@ map_insert_hash_dynamic :: proc "odin" (#no_alias m: ^Raw_Map, #no_alias info: ^
intrinsics.mem_copy_non_overlapping(rawptr(vp), rawptr(tv), size_of_v)
th := h
h = hp^
hp^ = th
h = hs[pos]
hs[pos] = th
distance = probe_distance
}
@@ -504,6 +457,103 @@ map_insert_hash_dynamic :: proc "odin" (#no_alias m: ^Raw_Map, #no_alias info: ^
pos = (pos + 1) & mask
distance += 1
}
// backward shift loop
hs[pos] = 0
look_ahead: uintptr = 1
for {
la_pos := (pos + look_ahead) & mask
element_hash := hs[la_pos]
if map_hash_is_deleted(element_hash) {
look_ahead += 1
hs[la_pos] = 0
continue
}
k_dst := map_cell_index_dynamic(ks, info.ks, pos)
v_dst := map_cell_index_dynamic(vs, info.vs, pos)
if map_hash_is_empty(element_hash) {
intrinsics.mem_copy_non_overlapping(rawptr(k_dst), rawptr(k), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v_dst), rawptr(v), size_of_v)
hs[pos] = h
return result if result != 0 else v_dst
}
k_src := map_cell_index_dynamic(ks, info.ks, la_pos)
v_src := map_cell_index_dynamic(vs, info.vs, la_pos)
probe_distance := map_probe_distance(m^, element_hash, la_pos)
if probe_distance < look_ahead {
// probed can be made ideal while placing saved (ending condition)
if result == 0 {
result = v_dst
}
intrinsics.mem_copy_non_overlapping(rawptr(k_dst), rawptr(k), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v_dst), rawptr(v), size_of_v)
hs[pos] = h
// This will be an ideal move
pos = (la_pos - probe_distance) & mask
look_ahead -= probe_distance
// shift until we hit ideal/empty
for probe_distance != 0 {
k_dst = map_cell_index_dynamic(ks, info.ks, pos)
v_dst = map_cell_index_dynamic(vs, info.vs, pos)
intrinsics.mem_copy_non_overlapping(rawptr(k_dst), rawptr(k_src), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v_dst), rawptr(v_src), size_of_v)
hs[pos] = element_hash
hs[la_pos] = 0
pos = (pos + 1) & mask
la_pos = (la_pos + 1) & mask
look_ahead = (la_pos - pos) & mask
element_hash = hs[la_pos]
if map_hash_is_empty(element_hash) {
return
}
probe_distance = map_probe_distance(m^, element_hash, la_pos)
if probe_distance == 0 {
return
}
// can be ideal?
if probe_distance < look_ahead {
pos = (la_pos - probe_distance) & mask
}
k_src = map_cell_index_dynamic(ks, info.ks, la_pos)
v_src = map_cell_index_dynamic(vs, info.vs, la_pos)
}
return
} else if distance < probe_distance - look_ahead {
// shift back probed
intrinsics.mem_copy_non_overlapping(rawptr(k_dst), rawptr(k_src), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v_dst), rawptr(v_src), size_of_v)
hs[pos] = element_hash
hs[la_pos] = 0
} else {
// place saved, save probed
if result == 0 {
result = v_dst
}
intrinsics.mem_copy_non_overlapping(rawptr(k_dst), rawptr(k), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v_dst), rawptr(v), size_of_v)
hs[pos] = h
intrinsics.mem_copy_non_overlapping(rawptr(k), rawptr(k_src), size_of_k)
intrinsics.mem_copy_non_overlapping(rawptr(v), rawptr(v_src), size_of_v)
h = hs[la_pos]
hs[la_pos] = 0
distance = probe_distance - look_ahead
}
pos = (pos + 1) & mask
distance += 1
}
}
@(require_results)
@@ -696,49 +746,19 @@ map_erase_dynamic :: #force_inline proc "contextless" (#no_alias m: ^Raw_Map, #n
m.len -= 1
ok = true
{ // coalesce tombstones
// HACK NOTE(bill): This is an ugly bodge but it is coalescing the tombstone slots
mask := (uintptr(1)<<map_log2_cap(m^)) - 1
curr_index := uintptr(index)
// TODO(bill): determine a good value for this empirically
// if we do not implement backward shift deletion
PROBE_COUNT :: 8
for _ in 0..<PROBE_COUNT {
next_index := (curr_index + 1) & mask
if next_index == index {
// looped around
break
}
// if the next element is empty or has zero probe distance, then any lookup
// will always fail on the next, so we can clear both of them
hash := hs[next_index]
if map_hash_is_empty(hash) || map_probe_distance(m^, hash, next_index) == 0 {
hs[curr_index] = 0
return
}
// now the next element will have a probe count of at least one,
// so it can use the delete slot instead
hs[curr_index] = hs[next_index]
mem_copy_non_overlapping(
rawptr(map_cell_index_dynamic(ks, info.ks, curr_index)),
rawptr(map_cell_index_dynamic(ks, info.ks, next_index)),
int(info.ks.size_of_type),
)
mem_copy_non_overlapping(
rawptr(map_cell_index_dynamic(vs, info.vs, curr_index)),
rawptr(map_cell_index_dynamic(vs, info.vs, next_index)),
int(info.vs.size_of_type),
)
curr_index = next_index
}
mask := (uintptr(1)<<map_log2_cap(m^)) - 1
curr_index := uintptr(index)
next_index := (curr_index + 1) & mask
// if the next element is empty or has zero probe distance, then any lookup
// will always fail on the next, so we can clear both of them
hash := hs[next_index]
if map_hash_is_empty(hash) || map_probe_distance(m^, hash, next_index) == 0 {
hs[curr_index] = 0
} else {
hs[curr_index] |= TOMBSTONE_MASK
}
return
}