#pragma once
#include "llama.h"
#include "llama-cparams.h"
#include <bitset>
#include <cassert>
#include <cstring>
#include <map>
#include <set>
#include <vector>
struct llama_kv_cell_ext {
// 2D spatial positions, typically used for M-RoPE
llama_pos x = 0;
llama_pos y = 0;
// return true if the current 2D spatial position is greater than other
bool is_2d_gt(llama_pos ox, llama_pos oy) const {
return (y > oy) || (y == oy && x > ox);
}
void reset() {
static_assert(std::is_trivially_copyable_v<llama_kv_cell_ext>);
memset(this, 0, sizeof(*this));
}
};
// meta information about KV cells that can be part of multiple sequences at the same time
// TODO: add unit tests
class llama_kv_cells {
public:
void reset() {
for (uint32_t i = 0; i < pos.size(); ++i) {
pos[i] = -1;
ext[i].reset();
shift[i] = 0;
seq[i].reset();
}
has_shift = false;
used.clear();
for (uint32_t s = 0; s < LLAMA_MAX_SEQ; ++s) {
seq_pos[s].clear();
}
}
void reset_shift() {
has_shift = false;
for (uint32_t i = 0; i < shift.size(); ++i) {
shift[i] = 0;
}
}
uint32_t size() const {
return pos.size();
}
void resize(uint32_t n) {
pos.resize(n);
ext.resize(n);
shift.resize(n);
seq.resize(n);
reset();
}
bool is_empty(uint32_t i) const {
assert(i < pos.size());
assert((pos[i] < 0 && pos[i] == -1) || pos[i] >= 0);
return pos[i] == -1;
}
uint32_t get_used() const {
return used.size();
}
// the index of the first cell that is used
// return 0 if no cells are used
uint32_t used_min() const {
return used.empty() ? 0 : *used.begin();
}
// the index of the last cell that is used + 1
// return 0 if no cells are used
uint32_t used_max_p1() const {
return used.empty() ? 0 : *used.rbegin() + 1;
}
bool get_has_shift() const {
return has_shift;
}
// move cell isrc to idst (used during defrag)
//void mv(uint32_t isrc, uint32_t idst) {
// assert(isrc < pos.size());
// assert(idst < pos.size());
// assert(pos[idst] == -1);
// assert(pos[isrc] != -1);
// pos [idst] = pos [isrc];
// shift[idst] = shift[isrc];
// seq [idst] = seq [isrc];
// pos [isrc] = -1;
// shift[isrc] = 0;
// seq [isrc].reset();
// used.erase (isrc);
// used.insert(idst);
//}
// copy the state of cells [i, i + n) (used for save/restore the state of the cells)
llama_kv_cells cp(uint32_t i, uint32_t n) const {
assert(i + n <= pos.size());
llama_kv_cells res;
res.resize(n);
for (uint32_t j = 0; j < n; ++j) {
const auto idx = i + j;
res.pos[j] = pos[idx];
res.ext[j] = ext[idx];
res.seq[j] = seq[idx];
assert(shift[idx] == 0);
}
return res;
}
// copy the state of cells [idxs[0], idxs[1], ..., idxs[idxs.size() - 1])
llama_kv_cells cp(const std::vector<uint32_t> & idxs) const {
llama_kv_cells res;
res.resize(idxs.size());
for (uint32_t j = 0; j < idxs.size(); ++j) {
const auto idx = idxs[j];
res.pos[j] = pos[idx];
res.ext[j] = ext[idx];
res.seq[j] = seq[idx];
assert(shift[idx] == 0);
}
return res;
}
// set the state of cells [i, i + other.pos.size()) (used for save/restore the state of the cells)
void set(uint32_t i, const llama_kv_cells & other) {
assert(i + other.pos.size() <= pos.size());
for (uint32_t j = 0; j < other.pos.size(); ++j) {
const auto idx = i + j;
if (pos[idx] == -1 && other.pos[j] != -1) {
used.insert(i + j);
}
if (pos[idx] != -1 && other.pos[j] == -1) {
used.erase(i + j);
}
if (pos[idx] != -1) {
seq_pos_rm(i + j);
}
pos[idx] = other.pos[j];
ext[idx] = other.ext[j];
seq[idx] = other.seq[j];
if (pos[idx] != -1) {
seq_pos_add(i + j);
}
assert(shift[idx] == 0);
}
}
// set the state of cells [idxs[0], idxs[1], ..., idxs[idxs.size() - 1])
void set(const std::vector<uint32_t> & idxs, const llama_kv_cells & other) {
assert(idxs.size() == other.pos.size());
for (uint32_t j = 0; j < other.pos.size(); ++j) {
const auto idx = idxs[j];
if (pos[idx] == -1 && other.pos[j] != -1) {
used.insert(idx);
}
if (pos[idx] != -1 && other.pos[j] == -1) {
used.erase(idx);
}
if (pos[idx] != -1) {
seq_pos_rm(idx);
}
pos[idx] = other.pos[j];
ext[idx] = other.ext[j];
seq[idx] = other.seq[j];
if (pos[idx] != -1) {
seq_pos_add(idx);
}
assert(shift[idx] == 0);
}
}
// clear a non-empty cell
void rm(uint32_t i) {
assert(i < pos.size());
assert(pos[i] != -1);
seq_pos_rm(i);
seq[i].reset();
pos[i] = -1;
ext[i].reset();
shift[i] = 0;
used.erase(i);
}
// note: call only if the cell has seq_id
// return true if the cell becomes empty
bool seq_rm(uint32_t i, llama_seq_id seq_id) {
assert(i < pos.size());
assert(seq[i].test(seq_id));
assert(pos[i] != -1);
assert(seq_id >= 0);
seq[i].reset(seq_id);
seq_pos_dec(seq_id, pos[i]);
if (seq[i].none()) {
pos[i] = -1;
ext[i].reset();
shift[i] = 0;
used.erase(i);
return true;
}
return false;
}
// return true if the cell becomes empty (i.e. it did not contain seq_id before the call)
bool seq_keep(uint32_t i, llama_seq_id seq_id) {
assert(i < pos.size());
if (seq[i].test(seq_id)) {
seq_pos_rm(i);
seq[i].reset();
seq[i].set(seq_id);
seq_pos_inc(seq_id, pos[i]);
return false;
}
if (seq[i].any()) {
seq_pos_rm(i);
seq[i].reset();
pos[i] = -1;
ext[i].reset();
shift[i] = 0;
used.erase(i);
return true;
}
assert(pos[i] == -1);
return false;
}
// number of different sequences in the cell
int seq_count(uint32_t i) const {
assert(i < pos.size());
assert(pos[i] != -1);
return seq[i].count();
}
// check if the cell contains seq_id
bool seq_has(uint32_t i, llama_seq_id seq_id) const {
assert(i < pos.size());
assert(seq_id >= 0);
return seq[i].test(seq_id);
}
// note: call only if the cell is not empty and the seq_id is not in the cell
void seq_add(uint32_t i, llama_seq_id seq_id) {
assert(i < pos.size());
assert(pos[i] != -1);
assert(!seq[i].test(seq_id));
seq[i].set(seq_id);
seq_pos_inc(seq_id, pos[i]);
}
// return the sequence id of this cell
// note: call only for cells with exactly one sequence
llama_seq_id seq_get(uint32_t i) const {
assert(seq[i].count() == 1);
for (int s = 0; s < LLAMA_MAX_SEQ; ++s) {
if (seq[i].test(s)) {
return s;
}
}
return -1;
}
// the minimum position of sequence seq_id currently present in any of the cells
// return -1 if the sequence is not present
llama_pos seq_pos_min(llama_seq_id seq_id) const {
assert(seq_id >= 0);
assert(seq_id < LLAMA_MAX_SEQ);
if (seq_pos[seq_id].empty()) {
return -1;
}
assert(seq_pos[seq_id].begin()->second > 0);
return seq_pos[seq_id].begin()->first;
}
// the maximum position of sequence seq_id currently present in any of the cells
// return -1 if the sequence is not present
llama_pos seq_pos_max(llama_seq_id seq_id) const {
assert(seq_id >= 0);
assert(seq_id < LLAMA_MAX_SEQ);
if (seq_pos[seq_id].empty()) {
return -1;
}
assert(seq_pos[seq_id].rbegin()->second > 0);
return seq_pos[seq_id].rbegin()->first;
}
// note: call only if the cell is not empty
llama_pos pos_get(uint32_t i) const {
assert(i < pos.size());
assert(pos[i] != -1);
return pos[i];
}
const llama_kv_cell_ext & ext_get(uint32_t i) const {
assert(i < pos.size());
assert(pos[i] != -1);
return ext[i];
}
// note: call only if the cell is not empty
llama_pos get_shift(uint32_t i) const {
assert(i < pos.size());
assert(pos[i] != -1);
return shift[i];
}
// check if a cell is not empty and its position is within [p0, p1)
bool pos_in(uint32_t i, llama_pos p0, llama_pos p1) const {
assert(i < pos.size());
return pos[i] >= p0 && pos[i] < p1;
}
// set the position of an empty cell
// does not modify "has_shift"
// note: call only if the cell is empty
void pos_set(uint32_t i, llama_pos p) {
assert(i < pos.size());
assert(pos[i] == -1);
assert(seq[i].none());
pos[i] = p;
used.insert(i);
}
void ext_set(uint32_t i, llama_kv_cell_ext p) {
assert(i < ext.size());
ext[i] = p;
}
// pos[i] = pos[i] + d
// sets "has_shift" to true
// note: call only if the cell is not empty
bool pos_add(uint32_t i, llama_pos d) {
assert(i < pos.size());
assert(pos[i] != -1);
seq_pos_rm(i);
pos[i] += d;
shift[i] += d;
has_shift = true;
if (pos[i] < 0) {
seq[i].reset();
pos[i] = -1;
shift[i] = 0;
used.erase(i);
return true;
}
seq_pos_add(i);
return false;
}
// pos[i] = pos[i] + d, and the 2D position with it when move_ext is set (M-RoPE)
// does not modify "has_shift": the caller has already rotated the cell's K
// note: call only if the cell is not empty and pos[i] + d >= 0
void pos_move(uint32_t i, llama_pos d, bool move_ext) {
assert(i < pos.size());
assert(pos[i] != -1);
assert(pos[i] + d >= 0);
seq_pos_rm(i);
if (move_ext) {
ext[i].x += d;
ext[i].y += d;
}
pos[i] += d;
seq_pos_add(i);
}
// pos[i] = pos[i] / d
// sets "has_shift" to true
// note: call only if the cell is not empty
void pos_div(uint32_t i, int d) {
assert(i < pos.size());
assert(pos[i] != -1);
const llama_pos p_old = pos[i];
seq_pos_rm(i);
pos[i] /= d;
shift[i] += p_old - pos[i];
seq_pos_add(i);
has_shift = true;
}
private:
bool has_shift = false;
// set of indices of used cells (i.e. pos[i] != -1, allowed to not have any seq_id)
std::set<uint32_t> used;
std::vector<llama_pos> pos;
// stores extra info per cell
std::vector<llama_kv_cell_ext> ext;
// this array accumulates any applied shifts to the pos array since the last reset_shift() call
// this is used to queue multiple updates to the pos array, which in the end can be applied in one go:
//
// cells.pos_add(x, shift_x);
// cells.pos_div(y, shift_y);
// ...
//
// if (cells.has_shift()) {
// for (int i = 0; i < n; ++i) {
// auto shift_i = cells.get_shift(i);
// ...
// }
// cells.reset_shift();
// }
//
std::vector<llama_pos> shift;
using seq_set_t = std::bitset<LLAMA_MAX_SEQ>;
// the bitset seq[i] tells us which sequences are currently occupying the i-th cell
std::vector<seq_set_t> seq;
// the set seq_pos[s][p] tells us how many times the position p is currently present for sequence s
// if the position p is not present, seq_pos[s][p] is not set
// this way seq_pos[s].begin() and seq_pos[s].rbegin() give us the min/max positions currently in the cache
//
// note that we cannot a use an std::set because in some cases a position can occur more than once for the same seq:
// - during performing a cache reuse via (rm + add)
// - some vision models have input embeddings with repeating positions
//
std::map<llama_pos, int> seq_pos[LLAMA_MAX_SEQ];
// helper functions for updating `seq_pos`, once cell at a time:
void seq_pos_dec(llama_seq_id s, llama_pos p) {
auto it = seq_pos[s].find(p);
assert(it != seq_pos[s].end());
if (--it->second == 0) {
seq_pos[s].erase(it);
}
}
void seq_pos_inc(llama_seq_id s, llama_pos p) {
seq_pos[s][p]++;
}
// remove cell i
void seq_pos_rm(uint32_t i) {
for (int s = 0; s < LLAMA_MAX_SEQ; ++s) {
if (seq[i].test(s)) {
seq_pos_dec(s, pos[i]);
}
}
}
// add cell i
void seq_pos_add(uint32_t i) {
for (int s = 0; s < LLAMA_MAX_SEQ; ++s) {
if (seq[i].test(s)) {
seq_pos_inc(s, pos[i]);
}
}
}
};
using llama_kv_cells_vec = std::vector<llama_kv_cells>;