diff --git a/common/arg.cpp b/common/arg.cpp
index 205177d46..8969fc107 100644
--- a/common/arg.cpp
+++ b/common/arg.cpp
@@ -1788,6 +1788,13 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
params.n_threads_http = value;
}
).set_examples({LLAMA_EXAMPLE_SERVER}).set_env("LLAMA_ARG_THREADS_HTTP"));
+ add_opt(common_arg(
+ {"--cache-reuse"}, "N",
+ string_format("min chunk size to attempt reusing from the cache via KV shifting (default: %d)", params.n_cache_reuse),
+ [](common_params & params, int value) {
+ params.n_cache_reuse = value;
+ }
+ ).set_examples({LLAMA_EXAMPLE_SERVER}).set_env("LLAMA_ARG_CACHE_REUSE"));
add_opt(common_arg(
{"--metrics"},
string_format("enable prometheus compatible metrics endpoint (default: %s)", params.endpoint_metrics ? "enabled" : "disabled"),
diff --git a/common/common.h b/common/common.h
index 71e686156..5507b1c59 100644
--- a/common/common.h
+++ b/common/common.h
@@ -277,7 +277,8 @@ struct common_params {
int32_t port = 8080; // server listens on this network port
int32_t timeout_read = 600; // http read timeout in seconds
int32_t timeout_write = timeout_read; // http write timeout in seconds
- int n_threads_http = -1; // number of threads to process HTTP requests (TODO: support threadpool)
+ int32_t n_threads_http = -1; // number of threads to process HTTP requests (TODO: support threadpool)
+ int32_t n_cache_reuse = 0; // min chunk size to reuse from the cache via KV shifting
std::string hostname = "127.0.0.1";
std::string public_path = ""; // NOLINT
diff --git a/examples/server/README.md b/examples/server/README.md
index b5feeb77b..cd0eaf847 100644
--- a/examples/server/README.md
+++ b/examples/server/README.md
@@ -147,6 +147,7 @@ The project is under active development, and we are [looking for feedback and co
| `--ssl-cert-file FNAME` | path to file a PEM-encoded SSL certificate
(env: LLAMA_ARG_SSL_CERT_FILE) |
| `-to, --timeout N` | server read/write timeout in seconds (default: 600)
(env: LLAMA_ARG_TIMEOUT) |
| `--threads-http N` | number of threads used to process HTTP requests (default: -1)
(env: LLAMA_ARG_THREADS_HTTP) |
+| `--cache-reuse N` | min chunk size to attempt reusing from the cache via KV shifting (default: 0)
(env: LLAMA_ARG_CACHE_REUSE) |
| `--metrics` | enable prometheus compatible metrics endpoint (default: disabled)
(env: LLAMA_ARG_ENDPOINT_METRICS) |
| `--slots` | enable slots monitoring endpoint (default: disabled)
(env: LLAMA_ARG_ENDPOINT_SLOTS) |
| `--props` | enable changing global properties via POST /props (default: disabled)
(env: LLAMA_ARG_ENDPOINT_PROPS) |
diff --git a/examples/server/server.cpp b/examples/server/server.cpp
index f809c46d5..015b3b2c5 100644
--- a/examples/server/server.cpp
+++ b/examples/server/server.cpp
@@ -800,7 +800,7 @@ struct server_context {
int slot_prompt_len = slot_prompt.size();
// length of the Longest Common Prefix between the current slot's prompt and the input prompt
- int lcp_len = common_part(slot_prompt, prompt);
+ int lcp_len = longest_common_prefix(slot_prompt, prompt);
// fraction of the common substring length compared to the current slot's prompt length
similarity = static_cast(lcp_len) / slot_prompt_len;
@@ -2012,7 +2012,7 @@ struct server_context {
}
slot.params.n_keep = std::min(slot.n_ctx - 4, slot.params.n_keep);
- // if input prompt is too big, truncate it (if group attention self-extend is disabled)
+ // if input prompt is too big, truncate it
if (slot.n_prompt_tokens >= slot.n_ctx) {
const int n_left = slot.n_ctx - slot.params.n_keep;
@@ -2042,12 +2042,74 @@ struct server_context {
if (slot.params.cache_prompt) {
// reuse any previously computed tokens that are common with the new prompt
- slot.n_past = common_part(slot.cache_tokens, prompt_tokens);
+ slot.n_past = longest_common_prefix(slot.cache_tokens, prompt_tokens);
// push the prompt into the sampling context (do not apply grammar)
for (int i = 0; i < slot.n_past; ++i) {
common_sampler_accept(slot.smpl, slot.cache_tokens[i], false);
}
+
+ // reuse chunks from the cached prompt by shifting their KV cache in the new position
+ if (params.n_cache_reuse > 0) {
+ size_t head_c = slot.n_past; // cache
+ size_t head_p = slot.n_past; // current prompt
+
+ SLT_DBG(slot, "trying to reuse chunks with size > %d, slot.n_past = %d\n", params.n_cache_reuse, slot.n_past);
+
+ while (head_c < slot.cache_tokens.size() &&
+ head_p < prompt_tokens.size()) {
+ if (llama_token_is_control(model, slot.cache_tokens[head_c])) {
+ break;
+ }
+
+ if (llama_token_is_control(model, prompt_tokens[head_p])) {
+ break;
+ }
+
+ size_t n_match = 0;
+
+ while (head_c + n_match < slot.cache_tokens.size() &&
+ head_p + n_match < prompt_tokens.size() &&
+ slot.cache_tokens[head_c + n_match] == prompt_tokens[head_p + n_match]) {
+ if (llama_token_is_control(model, slot.cache_tokens[head_c + n_match])) {
+ break;
+ }
+
+ if (llama_token_is_control(model, prompt_tokens[head_p + n_match])) {
+ break;
+ }
+
+ n_match++;
+ }
+
+ if (n_match >= (size_t) params.n_cache_reuse) {
+ SLT_DBG(slot, "reusing chunk with size %zu, shifting KV cache [%zu, %zu) -> [%zu, %zu)\n", n_match, head_c, head_c + n_match, head_p, head_p + n_match);
+ //for (size_t i = head_p; i < head_p + n_match; i++) {
+ // SLT_DBG(slot, "cache token %3zu: %6d '%s'\n", i, prompt_tokens[i], common_token_to_piece(ctx, prompt_tokens[i]).c_str());
+ //}
+
+ const int64_t kv_shift = (int64_t) head_p - (int64_t) head_c;
+
+ llama_kv_cache_seq_rm (ctx, slot.id + 1, head_p, head_c);
+ llama_kv_cache_seq_add(ctx, slot.id + 1, head_c, -1, kv_shift);
+
+ for (size_t i = 0; i < n_match; i++) {
+ slot.cache_tokens[head_p + i] = slot.cache_tokens[head_c + i];
+
+ common_sampler_accept(slot.smpl, slot.cache_tokens[head_p + i], false);
+
+ slot.n_past++;
+ }
+
+ head_c += n_match;
+ head_p += n_match;
+ } else {
+ head_c += 1;
+ }
+ }
+
+ SLT_DBG(slot, "after context reuse, new slot.n_past = %d\n", slot.n_past);
+ }
}
}
@@ -3257,6 +3319,7 @@ int main(int argc, char ** argv) {
ctx_server.queue_tasks.on_new_task(std::bind(
&server_context::process_single_task, &ctx_server, std::placeholders::_1));
+
ctx_server.queue_tasks.on_update_slots(std::bind(
&server_context::update_slots, &ctx_server));
diff --git a/examples/server/utils.hpp b/examples/server/utils.hpp
index ad99e9574..37999604d 100644
--- a/examples/server/utils.hpp
+++ b/examples/server/utils.hpp
@@ -195,14 +195,14 @@ static std::string gen_chatcmplid() {
// other common utils
//
-static size_t common_part(const std::vector & a, const std::vector & b) {
+static size_t longest_common_prefix(const std::vector & a, const std::vector & b) {
size_t i;
for (i = 0; i < a.size() && i < b.size() && a[i] == b[i]; i++) {}
return i;
}
-static size_t common_part(const std::string & a, const std::string & b) {
+static size_t longest_common_prefix(const std::string & a, const std::string & b) {
size_t i;
for (i = 0; i < a.size() && i < b.size() && a[i] == b[i]; i++) {}