cont : support non-continuous slots

ggml-ci

Author: ggerganov

src/llama-kv-cache-unified.cpp

@@ -400,8 +400,11 @@ llama_kv_cache_unified::slot_info_vec_t llama_kv_cache_unified::prepare(const st
     bool success = true;
 
     for (const auto & ubatch : ubatches) {
+        // non-continuous slots require support for ggml_set_rows()
+        const bool cont = supports_set_rows ? false : true;
+
         // only find a suitable slot for the ubatch. don't modify the cells yet
-        const auto sinfo_new = find_slot(ubatch);
+        const auto sinfo_new = find_slot(ubatch, cont);
         if (sinfo_new.empty()) {
             success = false;
             break;
@@ -521,7 +524,7 @@ bool llama_kv_cache_unified::update(llama_context * lctx, bool do_shift, const d
     return updated;
 }
 
-llama_kv_cache_unified::slot_info llama_kv_cache_unified::find_slot(const llama_ubatch & ubatch) const {
+llama_kv_cache_unified::slot_info llama_kv_cache_unified::find_slot(const llama_ubatch & ubatch, bool cont) const {
     const uint32_t n_tokens = ubatch.n_tokens;
 
     uint32_t head_cur = this->head;
@@ -595,17 +598,25 @@ llama_kv_cache_unified::slot_info llama_kv_cache_unified::find_slot(const llama_
         }
     }
 
+    uint32_t n_found  = 0;
     uint32_t n_tested = 0;
 
+    const uint32_t n_test = cont ? n_tokens : 1;
+
+    slot_info res;
+
+    res.idxs.resize(n_tokens);
+
     while (true) {
-        if (head_cur + n_tokens > cells.size()) {
+        if (head_cur + n_test > cells.size()) {
             n_tested += cells.size() - head_cur;
             head_cur = 0;
             continue;
         }
 
-        bool found = true;
-        for (uint32_t i = 0; i < n_tokens; i++) {
+        for (uint32_t i = 0; i < n_test; i++) {
+            const auto idx = head_cur;
+
             //const llama_pos    pos    = ubatch.pos[i];
             //const llama_seq_id seq_id = ubatch.seq_id[i][0];
 
@@ -615,19 +626,19 @@ llama_kv_cache_unified::slot_info llama_kv_cache_unified::find_slot(const llama_
             //    - (disabled) mask causally, if the sequence is the same as the one we are inserting
             //    - mask SWA, using current max pos for that sequence in the cache
             //                always insert in the cell with minimum pos
-            bool can_use = cells.is_empty(head_cur + i);
+            bool can_use = cells.is_empty(idx);
 
-            if (!can_use && cells.seq_count(head_cur + i) == 1) {
-                const llama_pos pos_cell = cells.pos_get(head_cur + i);
+            if (!can_use && cells.seq_count(idx) == 1) {
+                const llama_pos pos_cell = cells.pos_get(idx);
 
                 // (disabled) causal mask
                 // note: it's better to purge any "future" tokens beforehand
-                //if (cells.seq_has(head_cur + i, seq_id)) {
+                //if (cells.seq_has(idx, seq_id)) {
                 //    can_use = pos_cell >= pos;
                 //}
 
                 if (!can_use) {
-                    const llama_seq_id seq_id_cell = cells.seq_get(head_cur + i);
+                    const llama_seq_id seq_id_cell = cells.seq_get(idx);
 
                     // SWA mask
                     if (is_masked_swa(pos_cell, cells.seq_pos_max(seq_id_cell) + 1)) {
@@ -636,29 +647,35 @@ llama_kv_cache_unified::slot_info llama_kv_cache_unified::find_slot(const llama_
                 }
             }
 
-            if (!can_use) {
-                found = false;
-                head_cur += i + 1;
-                n_tested += i + 1;
+            head_cur++;
+            n_tested++;
+
+            if (can_use) {
+                res.idxs[n_found] = idx;
+
+                n_found++;
+            } else {
                 break;
             }
         }
 
-        if (found) {
+        if (n_found == n_tokens) {
             break;
         }
 
+        if (cont) {
+            n_found = 0;
+        }
+
         if (n_tested >= cells.size()) {
             //LLAMA_LOG_ERROR("%s: failed to find a slot for %d tokens\n", __func__, n_tokens);
             return { };
         }
     }
 
-    slot_info res;
-
-    res.idxs.resize(n_tokens);
-    for (uint32_t i = 0; i < n_tokens; ++i) {
-        res.idxs[i] = head_cur + i;
+    // we didn't find a suitable slot - return empty result
+    if (n_found < n_tokens) {
+        res.clear();
     }
 
     return res;
@@ -1592,7 +1609,7 @@ bool llama_kv_cache_unified::state_read_meta(llama_io_read_i & io, uint32_t cell
             ubatch.seq_id[i]   = &dest_seq_id;
         }
 
-        const auto sinfo = find_slot(ubatch);
+        const auto sinfo = find_slot(ubatch, true);
         if (sinfo.empty()) {
             LLAMA_LOG_ERROR("%s: failed to find available cells in kv cache\n", __func__);
             return false;

src/llama-kv-cache-unified.h

@@ -49,6 +49,10 @@ class llama_kv_cache_unified : public llama_memory_i {
             return idxs.empty();
         }
 
+        void clear() {
+            idxs.clear();
+        }
+
         // TODO: implement
         //std::vector<idx_vec_t> seq_idxs;
     };
@@ -133,14 +137,10 @@ class llama_kv_cache_unified : public llama_memory_i {
 
     bool update(llama_context * lctx, bool do_shift, const defrag_info & dinfo);
 
-    // find a continuous slot of kv cells that can hold the ubatch
-    // return the cell position where we can insert the ubatch
-    // return -1 on failure to find a slot
-    slot_info find_slot(const llama_ubatch & ubatch) const;
-
-    // find a set of kv cells that can hold the ubatch
-    // TODO: implement
-    //slot_info find_slot_ext(const llama_ubatch & ubatch) const;
+    // find a slot of kv cells that can hold the ubatch
+    // if cont == true, then the slot must be continuous
+    // return empty slot_info on failure
+    slot_info find_slot(const llama_ubatch & ubatch, bool cont) const;
 
     // emplace the ubatch context into slot: [sinfo.idxs[0...ubatch.n_tokens - 1]]
     void apply_ubatch(const slot_info & sinfo, const llama_ubatch & ubatch);