llama.cpp/examples/speculative-simple/speculative-simple.cpp
Diego Devesa 10bce0450f
llama : accept a list of devices to use to offload a model (#10497)
* llama : accept a list of devices to use to offload a model

* accept `--dev none` to completely disable offloading

* fix dev list with dl backends

* rename env parameter to LLAMA_ARG_DEVICE for consistency
2024-11-25 19:30:06 +01:00

275 lines
8.7 KiB
C++

#include "arg.h"
#include "common.h"
#include "sampling.h"
#include "speculative.h"
#include "log.h"
#include "llama.h"
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
int main(int argc, char ** argv) {
common_params params;
if (!common_params_parse(argc, argv, params, LLAMA_EXAMPLE_SPECULATIVE)) {
return 1;
}
if (params.n_predict < -1) {
LOG_ERR("%s: --n-predict must be >= -1\n", __func__);
return 1;
}
common_init();
if (params.speculative.model.empty()) {
LOG_ERR("%s: --model-draft is required\n", __func__);
return 1;
}
// init llama.cpp
llama_backend_init();
llama_numa_init(params.numa);
llama_model * model_tgt = NULL;
llama_model * model_dft = NULL;
llama_context * ctx_tgt = NULL;
llama_context * ctx_dft = NULL;
// load the target model
common_init_result llama_init_tgt = common_init_from_params(params);
model_tgt = llama_init_tgt.model;
ctx_tgt = llama_init_tgt.context;
// load the draft model
params.devices = params.speculative.devices;
params.model = params.speculative.model;
params.n_ctx = params.speculative.n_ctx;
params.n_batch = params.speculative.n_ctx > 0 ? params.speculative.n_ctx : params.n_batch;
params.n_gpu_layers = params.speculative.n_gpu_layers;
if (params.speculative.cpuparams.n_threads > 0) {
params.cpuparams.n_threads = params.speculative.cpuparams.n_threads;
}
params.cpuparams_batch.n_threads = params.speculative.cpuparams_batch.n_threads;
common_init_result llama_init_dft = common_init_from_params(params);
model_dft = llama_init_dft.model;
ctx_dft = llama_init_dft.context;
if (!common_speculative_are_compatible(ctx_tgt, ctx_dft)) {
return 1;
}
// Tokenize the prompt
std::vector<llama_token> inp;
inp = common_tokenize(ctx_tgt, params.prompt, true, true);
if (llama_n_ctx(ctx_tgt) < (int) inp.size()) {
LOG_ERR("%s: the prompt exceeds the context size (%d tokens, ctx %d)\n", __func__, (int) inp.size(), llama_n_ctx(ctx_tgt));
return 1;
}
if (llama_n_batch(ctx_tgt) < (int) inp.size()) {
LOG_ERR("%s: the prompt exceeds the batch size (%d tokens, batch %d)\n", __func__, (int) inp.size(), llama_n_batch(ctx_tgt));
return 1;
}
LOG("\n\n");
for (auto id : inp) {
LOG("%s", common_token_to_piece(ctx_tgt, id).c_str());
}
// how many tokens to draft each time
int n_draft = params.speculative.n_max;
int n_draft_min = params.speculative.n_min;
float p_min = params.speculative.p_min;
int n_predict = 0;
int n_drafted = 0;
int n_accept = 0;
// used to determine end of generation
bool has_eos = false;
// ================================================
// everything until here is standard initialization
// the relevant stuff for speculative decoding starts here
const auto t_enc_start = ggml_time_us();
// target model sampling context
struct common_sampler * smpl = common_sampler_init(model_tgt, params.sampling);
// eval the prompt
llama_decode(ctx_tgt, llama_batch_get_one(inp.data(), inp.size() - 1));
// note: keep the last token separate!
llama_token id_last = inp.back();
// all tokens currently in the target context
auto prompt_tgt = std::vector<llama_token>(inp.begin(), inp.end() - 1);
int n_past = inp.size() - 1;
// init the speculator
struct common_speculative_params params_spec;
params_spec.n_draft = n_draft;
params_spec.n_reuse = llama_n_ctx(ctx_dft) - n_draft;
params_spec.p_min = p_min;
struct common_speculative * spec = common_speculative_init(ctx_dft);
llama_batch batch_tgt = llama_batch_init(llama_n_batch(ctx_tgt), 0, 1);
const auto t_enc_end = ggml_time_us();
const auto t_dec_start = ggml_time_us();
while (true) {
// optionally, generate draft tokens that can be appended to the target batch
//
// this is the most important part of the speculation. the more probable tokens that are provided here
// the better the performance will be. in theory, this computation can be performed asynchronously and even
// offloaded to a remote device. it doesn't even have to be based on an LLM. instead, it can provide tokens
// from a cache or lookup tables.
//
llama_tokens draft = common_speculative_gen_draft(spec, params_spec, prompt_tgt, id_last);
//LOG_DBG("draft: %s\n", string_from(ctx_dft, draft).c_str());
// always have a token to evaluate from before - id_last
common_batch_clear(batch_tgt);
common_batch_add (batch_tgt, id_last, n_past++, { 0 }, true);
// evaluate the target model on [id_last, draft0, draft1, ..., draftN-1]
{
// do not waste time on small drafts
if (draft.size() < n_draft_min) {
draft.clear();
}
for (size_t i = 0; i < draft.size(); ++i) {
common_batch_add(batch_tgt, draft[i], n_past + i, { 0 }, true);
}
//LOG_DBG("target batch: %s\n", string_from(ctx_tgt, batch_tgt).c_str());
llama_decode(ctx_tgt, batch_tgt);
}
// sample from the full target batch and return the accepted tokens based on the target sampler
//
// for each token to be accepted, the sampler would have to sample that same token
// in such cases, instead of decoding the sampled token as we normally do, we simply continue with the
// available logits from the batch and sample the next token until we run out of logits or the sampler
// disagrees with the draft
//
const auto ids = common_sampler_sample_and_accept_n(smpl, ctx_tgt, draft);
//LOG_DBG("ids: %s\n", string_from(ctx_tgt, ids).c_str());
GGML_ASSERT(ids.size() > 0); // there will always be at least one accepted token
n_past += ids.size() - 1;
n_drafted += batch_tgt.n_tokens - 1;
n_accept += ids.size() - 1;
// process the accepted tokens and update contexts
//
// this is the standard token post-processing that we normally do
// in this case, we do it for a group of accepted tokens at once
//
{
llama_token id;
std::string token_str;
for (size_t i = 0; i < ids.size(); ++i) {
id = ids[i];
++n_predict;
if (llama_token_is_eog(model_tgt, id)) {
has_eos = true;
break;
}
token_str = common_token_to_piece(ctx_tgt, id);
if (params.use_color && i + 1 < ids.size()) {
LOG("\u001b[%dm%s\u001b[37m", (36 - 0 % 6), token_str.c_str());
} else {
LOG("%s", token_str.c_str());
}
}
if ((params.n_predict >= 0 && n_predict > params.n_predict) || has_eos) {
break;
}
LOG_DBG("accepted %d/%d draft tokens, the last target token is: (%d, '%s')\n", (int) ids.size() - 1, (int) draft.size(), id, token_str.c_str());
{
LOG_DBG("clear kv cache from any extra tokens, n_past = %d\n", n_past);
llama_kv_cache_seq_rm(ctx_tgt, 0, n_past, -1);
}
prompt_tgt.push_back(id_last);
prompt_tgt.insert(prompt_tgt.end(), ids.begin(), ids.end() - 1);
// remember the last accepted token for the next iteration
id_last = id;
}
}
auto t_dec_end = ggml_time_us();
const int n_input = inp.size();
LOG("\n\n");
LOG_INF("encoded %4d tokens in %8.3f seconds, speed: %8.3f t/s\n", n_input, (t_enc_end - t_enc_start) / 1e6f, inp.size() / ((t_enc_end - t_enc_start) / 1e6f));
LOG_INF("decoded %4d tokens in %8.3f seconds, speed: %8.3f t/s\n", n_predict, (t_dec_end - t_dec_start) / 1e6f, n_predict / ((t_dec_end - t_dec_start) / 1e6f));
LOG_INF("\n");
LOG_INF("n_draft = %d\n", n_draft);
LOG_INF("n_predict = %d\n", n_predict);
LOG_INF("n_drafted = %d\n", n_drafted);
LOG_INF("n_accept = %d\n", n_accept);
LOG_INF("accept = %.3f%%\n", 100.0f * n_accept / n_drafted);
LOG_INF("\n");
LOG_INF("draft:\n\n");
llama_perf_context_print(ctx_dft);
LOG_INF("\n");
LOG_INF("target:\n\n");
common_perf_print(ctx_tgt, smpl);
common_sampler_free(smpl);
common_speculative_free(spec);
llama_free(ctx_tgt);
llama_free_model(model_tgt);
llama_free(ctx_dft);
llama_free_model(model_dft);
llama_backend_free();
LOG("\n\n");
return 0;
}