llama : kv cache

ggml-ci

Author: ggerganov

include/llama.h

@@ -556,6 +556,8 @@ extern "C" {
     // KV cache
     //
 
+    // TODO: remove llama_kv_cache_view_* API
+
     // Information associated with an individual cell in the KV cache view.
     struct llama_kv_cache_view_cell {
         // The position for this cell. Takes KV cache shifts into account.
@@ -602,8 +604,11 @@ extern "C" {
     LLAMA_API void llama_kv_cache_view_free(struct llama_kv_cache_view * view);
 
     // Update the KV cache view structure with the current state of the KV cache. (use only for debugging purposes)
+    // TODO: change signature to llama_kv_cache_view_update(struct llama_kv_cache_view * view, const struct llama_context * ctx)
     LLAMA_API void llama_kv_cache_view_update(const struct llama_context * ctx, struct llama_kv_cache_view * view);
 
+    ///
+
     // Returns the number of tokens in the KV cache (slow, use only for debug)
     // If a KV cell has multiple sequences assigned to it, it will be counted multiple times
     LLAMA_API int32_t llama_get_kv_cache_token_count(const struct llama_context * ctx);
@@ -673,6 +678,9 @@ extern "C" {
             struct llama_context * ctx,
                     llama_seq_id   seq_id);
 
+    // TODO: the llama_kv_cache_defrag and llama_kv_cache_update API tightly couples llama_context with llama_kv_cache
+    //       how to avoid this?
+
     // Defragment the KV cache
     // This will be applied:
     //   - lazily on next llama_decode()

src/llama-context.cpp

@@ -106,7 +106,6 @@ struct llama_data_write {
     }
 
     void write_kv_cache_meta(const llama_kv_cache & kv_self, const std::vector<std::pair<uint32_t, uint32_t>> & cell_ranges, llama_seq_id seq_id = -1) {
-
         for (const auto & range : cell_ranges) {
             for (uint32_t i = range.first; i < range.second; ++i) {
                 const auto & cell = kv_self.cells[i];

src/llama-context.h

@@ -2,6 +2,7 @@
 
 #include "llama-impl.h"
 #include "llama-batch.h"
+#include "llama-cparams.h"
 #include "llama-model.h"
 #include "llama-kv-cache.h"
 #include "llama-adapter.h"
@@ -13,38 +14,6 @@
 #include <vector>
 #include <set>
 
-struct llama_cparams {
-    uint32_t n_ctx;           // context size used during inference
-    uint32_t n_batch;
-    uint32_t n_ubatch;
-    uint32_t n_seq_max;
-    int      n_threads;       // number of threads to use for generation
-    int      n_threads_batch; // number of threads to use for batch processing
-
-    float rope_freq_base;
-    float rope_freq_scale;
-
-    uint32_t n_ctx_orig_yarn;
-    // These hyperparameters are not exposed in GGUF, because all
-    // existing YaRN models use the same values for them.
-    float yarn_ext_factor;
-    float yarn_attn_factor;
-    float yarn_beta_fast;
-    float yarn_beta_slow;
-    float defrag_thold;
-
-    bool embeddings;
-    bool causal_attn;
-    bool offload_kqv;
-    bool flash_attn;
-    bool no_perf;
-
-    enum llama_pooling_type pooling_type;
-
-    ggml_backend_sched_eval_callback cb_eval;
-    void * cb_eval_user_data;
-};
-
 struct llama_context {
     llama_context(const llama_model & model)
         : model(model)
@@ -140,112 +109,6 @@ struct llama_context {
     struct ggml_tensor * inp_KQ_mask_cross; // F32 [n_outputs_enc, n_batch]
 };
 
-static bool llama_kv_cache_init(
-             struct llama_kv_cache & cache,
-               const llama_context * ctx,
-                         ggml_type   type_k,
-                         ggml_type   type_v,
-                          uint32_t   kv_size,
-                              bool   offload) {
-    const llama_model & model = ctx->model;
-    const llama_cparams & cparams = ctx->cparams;
-
-    const struct llama_hparams & hparams = model.hparams;
-
-    const int32_t n_layer = hparams.n_layer;
-
-    LLAMA_LOG_INFO("%s: kv_size = %d, offload = %d, type_k = '%s', type_v = '%s', n_layer = %d\n", __func__, kv_size, offload, ggml_type_name(type_k), ggml_type_name(type_v), n_layer);
-
-    cache.has_shift = false;
-
-    cache.recurrent = llama_model_is_recurrent(&model);
-    cache.v_trans   = !cache.recurrent && !cparams.flash_attn;
-
-    cache.head = 0;
-    cache.size = kv_size;
-    cache.used = 0;
-
-    cache.type_k = type_k;
-    cache.type_v = type_v;
-
-    cache.cells.clear();
-    cache.cells.resize(kv_size);
-
-    // create a context for each buffer type
-    std::map<ggml_backend_buffer_type_t, ggml_context *> ctx_map;
-    auto ctx_for_buft = [&](ggml_backend_buffer_type_t buft) -> ggml_context * {
-        auto it = ctx_map.find(buft);
-        if (it == ctx_map.end()) {
-            struct ggml_init_params params = {
-                /*.mem_size   =*/ size_t(2u*n_layer*ggml_tensor_overhead()),
-                /*.mem_buffer =*/ NULL,
-                /*.no_alloc   =*/ true,
-            };
-            ggml_context * ctx = ggml_init(params);
-            if (!ctx) {
-                return nullptr;
-            }
-            ctx_map[buft] = ctx;
-            cache.ctxs.emplace_back(ctx);
-            return ctx;
-        }
-        return it->second;
-    };
-
-    cache.k_l.reserve(n_layer);
-    cache.v_l.reserve(n_layer);
-
-    for (int i = 0; i < n_layer; i++) {
-        const uint32_t n_embd_k_gqa = hparams.n_embd_k_gqa(i) + hparams.n_embd_k_s();
-        const uint32_t n_embd_v_gqa = hparams.n_embd_v_gqa(i) + hparams.n_embd_v_s();
-
-        LLAMA_LOG_DEBUG("%s: layer %d: n_embd_k_gqa = %d, n_embd_v_gqa = %d\n", __func__, i, n_embd_k_gqa, n_embd_v_gqa);
-
-        ggml_backend_buffer_type_t buft;
-        if (offload) {
-            auto * dev = model.dev_layer.at(i).dev;
-            buft = ggml_backend_dev_buffer_type(dev);
-        } else {
-            buft = ggml_backend_cpu_buffer_type();
-        }
-        ggml_context * ctx = ctx_for_buft(buft);
-
-        if (!ctx) {
-            LLAMA_LOG_ERROR("%s: failed to create ggml context for kv cache\n", __func__);
-            return false;
-        }
-
-        ggml_tensor * k = ggml_new_tensor_1d(ctx, type_k, n_embd_k_gqa*kv_size);
-        ggml_tensor * v = ggml_new_tensor_1d(ctx, type_v, n_embd_v_gqa*kv_size);
-        ggml_format_name(k, "cache_k_l%d", i);
-        ggml_format_name(v, "cache_v_l%d", i);
-        cache.k_l.push_back(k);
-        cache.v_l.push_back(v);
-    }
-
-    // allocate tensors and initialize the buffers to avoid NaNs in the padding
-    for (auto it : ctx_map) {
-        auto * buft = it.first;
-        auto * ctx  = it.second;
-
-        ggml_backend_buffer_t buf = ggml_backend_alloc_ctx_tensors_from_buft(ctx, buft);
-        if (!buf) {
-            LLAMA_LOG_ERROR("%s: failed to allocate buffer for kv cache\n", __func__);
-            return false;
-        }
-        ggml_backend_buffer_clear(buf, 0);
-        LLAMA_LOG_INFO("%s: %10s KV buffer size = %8.2f MiB\n", __func__, ggml_backend_buffer_name(buf), ggml_backend_buffer_get_size(buf)/1024.0/1024.0);
-        cache.bufs.emplace_back(buf);
-    }
-
-    return true;
-}
-
-static uint32_t llama_kv_cache_get_padding(const struct llama_cparams & cparams) {
-    // the FA kernels require padding to avoid extra runtime boundary checks
-    return cparams.flash_attn ? 256u : 32u;
-}
-
 // Make sure enough space is available for outputs.
 // Returns max number of outputs for which space was reserved.
 static size_t llama_output_reserve(llama_context & lctx, size_t n_outputs) {

src/llama-cparams.cpp

@@ -0,0 +1 @@
+#include "llama-cparams.h"

src/llama-cparams.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include "llama.h"
+
+#include <cstdint>
+
+struct llama_cparams {
+    uint32_t n_ctx;           // context size used during inference
+    uint32_t n_batch;
+    uint32_t n_ubatch;
+    uint32_t n_seq_max;
+    int      n_threads;       // number of threads to use for generation
+    int      n_threads_batch; // number of threads to use for batch processing
+
+    float rope_freq_base;
+    float rope_freq_scale;
+
+    uint32_t n_ctx_orig_yarn;
+    // These hyperparameters are not exposed in GGUF, because all
+    // existing YaRN models use the same values for them.
+    float yarn_ext_factor;
+    float yarn_attn_factor;
+    float yarn_beta_fast;
+    float yarn_beta_slow;
+    float defrag_thold;
+
+    bool embeddings;
+    bool causal_attn;
+    bool offload_kqv;
+    bool flash_attn;
+    bool no_perf;
+
+    enum llama_pooling_type pooling_type;
+
+    ggml_backend_sched_eval_callback cb_eval;
+    void * cb_eval_user_data;
+};