Make prompt cache saving and restoring MLA aware (#497)

* Remove kv_l, kvt_l and just use k_l and v_l

* Hopefully take care of missing V cache (MLA)

* Fix save and restore when there is no V cache

* Fix double print

* Update write_kv_cache_data and read_kv_cache_data to be MLA aware

---------

Co-authored-by: Iwan Kawrakow <[email protected]>

Author: saood06

src/llama.cpp

@@ -21448,13 +21448,15 @@ struct llama_data_write {
         // Get whole range at a time
         for (uint32_t il = 0; il < n_layer; ++il) {
             const uint32_t n_embd_k_gqa = hparams.n_embd_k_gqa(il) + hparams.n_embd_k_s();
+            const uint32_t n_embd_head_qk_rope = hparams.n_rot;
+            const uint32_t kv_lora_rank = hparams.n_lora_kv;
 
             // Write key type
             const int32_t k_type_i = (int32_t)kv_self.k_l[il]->type;
             write(&k_type_i, sizeof(k_type_i));
 
             // Write row size of key
-            const uint64_t k_size_row = ggml_row_size(kv_self.k_l[il]->type, n_embd_k_gqa);
+            const uint64_t k_size_row = (ctx->cparams.mla_attn == 0) ? ggml_row_size(kv_self.k_l[il]->type, n_embd_k_gqa) : ggml_row_size(kv_self.k_l[il]->type, kv_lora_rank + n_embd_head_qk_rope);
             write(&k_size_row, sizeof(k_size_row));
 
             // Read each range of cells of k_size length each into tmp_buf and write out
@@ -21758,6 +21760,9 @@ struct llama_data_read {
         // For each layer, read the keys for each cell, one row is one cell, read as one contiguous block
         for (uint32_t il = 0; il < n_layer; ++il) {
             const uint32_t n_embd_k_gqa = hparams.n_embd_k_gqa(il) + hparams.n_embd_k_s();
+            const uint32_t n_embd_head_qk_rope = hparams.n_rot;
+            const uint32_t kv_lora_rank = hparams.n_lora_kv;
+
 
             // Read type of key
             int32_t k_type_i_ref;
@@ -21771,7 +21776,7 @@ struct llama_data_read {
             // Read row size of key
             uint64_t k_size_row_ref;
             read_to(&k_size_row_ref, sizeof(k_size_row_ref));
-            const size_t k_size_row = ggml_row_size(kv_self.k_l[il]->type, n_embd_k_gqa);
+            const uint64_t k_size_row = (ctx->cparams.mla_attn == 0) ? ggml_row_size(kv_self.k_l[il]->type, n_embd_k_gqa) : ggml_row_size(kv_self.k_l[il]->type, kv_lora_rank + n_embd_head_qk_rope);
             if (k_size_row != k_size_row_ref) {
                 LLAMA_LOG_ERROR("%s: mismatched key row size (%zu != %zu, layer %d)\n", __func__, k_size_row, (size_t) k_size_row_ref, il);
                 return false;