feat: Update the logic in llama_decode_internal for kv_hybrid cache

Branch: BambaArchitecture

Signed-off-by: Gabe Goodhart <ghart@us.ibm.com>

src/llama.cpp

@@ -18104,6 +18104,11 @@ static int llama_decode_internal(
     auto & kv_self = lctx.kv_self;
     llama_kv_slot_restorer kv_slot_restorer(kv_self);
 
+    // Only used for hybrid-recurrent models (e.g. Bamba)
+    const bool hybrid = llama_model_is_hybrid(&model);
+    auto & kv_hybrid = lctx.kv_hybrid;
+    llama_kv_slot_restorer kv_slot_restorer_hybrid(kv_hybrid);
+
     const int64_t n_embd  = hparams.n_embd;
     const int64_t n_vocab = hparams.n_vocab;
 
@@ -18192,7 +18197,15 @@ static int llama_decode_internal(
                 return 1;
             }
             kv_slot_restorer.save(slot);
+            if (hybrid) {
+                const auto slot_hybrid = llama_kv_cache_find_slot(kv_hybrid, ubatch);
+                if (!slot_hybrid) {
+                    return 1;
+                }
+                kv_slot_restorer_hybrid.save(slot_hybrid);
+            }
 
+            // TODO: Update this clause for hybrid recurrent models
             if (!kv_self.recurrent) {
                 // a heuristic, to avoid attending the full cache if it is not yet utilized
                 // after enough generations, the benefit from this heuristic disappears
@@ -18241,6 +18254,9 @@ static int llama_decode_internal(
         const auto compute_status = llama_graph_compute(lctx, gf, n_threads, threadpool);
         if (compute_status != GGML_STATUS_SUCCESS) {
             kv_slot_restorer.restore(kv_self);
+            if (hybrid) {
+                kv_slot_restorer_hybrid.restore(kv_hybrid);
+            }
             switch (compute_status) {
                 case GGML_STATUS_ABORTED:
                     return 2;
@@ -18252,7 +18268,7 @@ static int llama_decode_internal(
             }
         }
 
-        // update the kv ring buffer
+        // update the kv ring buffer(s)
         {
             kv_self.head += n_tokens;
 
@@ -18260,6 +18276,13 @@ static int llama_decode_internal(
             if (kv_self.head >= kv_self.size) {
                 kv_self.head = 0;
             }
+
+            if (hybrid) {
+                kv_hybrid.head += n_tokens;
+                if (kv_hybrid.head >= kv_hybrid.size) {
+                    kv_hybrid.head = 0;
+                }
+            }
         }
 
         // plot the computation graph in dot format (for debugging purposes)
@@ -18366,7 +18389,7 @@ static int llama_decode_internal(
     // wait for the computation to finish (automatically done when obtaining the model output)
     //llama_synchronize(&lctx);
 
-    // decide if we need to defrag the kv cache
+    // decide if we need to defrag the kv cache(s)
     if (cparams.causal_attn && cparams.defrag_thold >= 0.0f) {
         const float fragmentation = kv_self.n >= 128 ? 1.0f - float(kv_self.used)/float(kv_self.n) : 0.0f;
 
@@ -18376,6 +18399,13 @@ static int llama_decode_internal(
 
             llama_kv_cache_defrag(kv_self);
         }
+
+        if (hybrid) {
+            const float fragmentation = kv_hybrid.n >= 128 ? 1.0f - float(kv_hybrid.used)/float(kv_hybrid.n) : 0.0f;
+            if (fragmentation > cparams.defrag_thold) {
+                llama_kv_cache_defrag(kv_hybrid);
+            }
+        }
     }
 
     // Reset state for the next token before backend sync, to allow the CPU activities in the reset to