feat(backend): entirely rewrite backend

This commit is contained in:
Morgan Funtowicz 2024-10-30 22:40:37 +01:00
parent 611590440d
commit b98c635781
2 changed files with 245 additions and 88 deletions

View File

@ -16,55 +16,89 @@
namespace huggingface::tgi::backends::llamacpp {
std::unique_ptr<llama_sampler> SamplingParams::IntoLlamaSampler(const llama_model *pModel) const {
void llama_batch_fill_prompt(llama_batch &batch, std::span<const llama_token> input_tokens) {
for (auto i = 0; i < input_tokens.size(); ++i) {
batch.token[i] = input_tokens[i];
batch.pos[i] = i;
batch.n_seq_id[i] = 1;
batch.seq_id[i] = 0;
batch.logits[i] = false;
++batch.n_tokens;
}
batch.logits[batch.n_tokens] = true;
}
std::unique_ptr<llama_sampler> sampling_params_t::into_llama_sampler(const llama_model *model) const {
auto *pSampler = llama_sampler_chain_init({.no_perf = false});
// Penalties
llama_sampler_chain_add(pSampler, llama_sampler_init_penalties(
llama_n_vocab(pModel),
llama_token_eos(pModel),
llama_token_nl(pModel),
llama_n_vocab(model),
llama_token_eos(model),
llama_token_nl(model),
0.0f,
repetitionPenalty,
frequencyPenalty,
repetition_penalty,
frequency_penalty,
0.0f,
false,
false
));
llama_sampler_chain_add(pSampler, llama_sampler_init_top_k(static_cast<int32_t>(topK)));
llama_sampler_chain_add(pSampler, llama_sampler_init_top_k(static_cast<int32_t>(top_k)));
if (0 < topP && topP < 1) {
llama_sampler_chain_add(pSampler, llama_sampler_init_top_p(topP, 1));
if (0 < top_p && top_p < 1) {
llama_sampler_chain_add(pSampler, llama_sampler_init_top_p(top_p, 1));
}
llama_sampler_chain_add(pSampler, llama_sampler_init_dist(seed));
return std::unique_ptr<llama_sampler>(pSampler);
}
Worker::Worker(std::shared_ptr<llama_model> pModel, const llama_context_params &params)
: mModel_(pModel), mParams_(params) {
worker_t::worker_t(std::shared_ptr<llama_model> model, const llama_context_params &params)
: mModel_(model), mParams_(params) {
#ifdef TGI_LLAMACPP_BACKEND_DEBUG
char modelName[256];
llama_model_meta_val_str(pModel.get(), "general.name", modelName, sizeof(modelName));
llama_model_meta_val_str(model.get(), "general.name", modelName, sizeof(modelName));
SPDLOG_DEBUG(FMT_STRING("Created llama.cpp backend for model: '{}'"), std::string_view(modelName));
#endif
}
void Worker::Loop(std::atomic_flag &running, std::atomic_uint8_t &waiting, std::queue<SamplingParams> &backlog) {
void worker_t::loop(std::stop_source &driver, std::queue<generation_context_t> &backlog) const {
auto *context = llama_new_context_with_model(mModel_.get(), mParams_);
while (running.test(std::memory_order_acquire)) {
if (waiting.load(std::memory_order_acquire) > 0) {
--waiting;
while (!driver.stop_requested()) {
const auto generation_context = backlog.front();
auto request = backlog.front();
auto sampler = request.IntoLlamaSampler(mModel_.get());
generate(context, generation_context, std::nullopt);
backlog.pop();
SPDLOG_DEBUG("Processed request ({:d} remaining)", backlog.size());
}
llama_free(context);
}
size_t worker_t::generate(
llama_context *context,
const generation_context_t &generation_context,
const std::optional<llama_decode_callback> &callback) const {
// Store information about context and generation size
auto prompt_length = std::ssize(generation_context.input_tokens);
auto max_new_tokens = generation_context.generation_params.max_new_tokens;
// Convert sampling params to what llama.cpp is looking for
auto sampler = generation_context.sampling_params.into_llama_sampler(mModel_.get());
// Setup the prompt
auto copy = std::vector(generation_context.input_tokens.begin(), generation_context.input_tokens.end());
auto batch = llama_batch_get_one(copy.data(), copy.size());
// Retrieve decoding context
auto batch = llama_batch_get_one(tokens.data(), tokens.size());
// Decode
for (auto [generating, nDecoded] = std::pair{true, 0uz}; generating && nDecoded < 1; ++nDecoded) {
auto n_decoded_tokens = 0;
for (bool generating = true; generating && n_decoded_tokens < max_new_tokens; ++n_decoded_tokens) {
const auto callback_ = callback.value_or(llama_void_callback);
#ifdef TGI_LLAMACPP_BACKEND_DEBUG
const auto start = std::chrono::steady_clock::now();
const auto status = llama_decode(context, batch);
@ -74,27 +108,64 @@ namespace huggingface::tgi::backends::llamacpp {
#else
const auto status = llama_decode(ctx, batch);
#endif
batch.n_tokens = 0;
if (LLAMA_SUCCESS(status)) {
// Sample the new token
auto new_token_id = llama_sampler_sample(sampler.get(), context, -1);
generated.emplace_back(new_token_id);
generating = !llama_token_is_eog(mModel_.get(), new_token_id);
auto is_eos = llama_token_is_eog(mModel_.get(), new_token_id);
generation_context.generated_tokens[n_decoded_tokens] = new_token_id;
generating = !is_eos;
// Bubble up the generated token if a callback is provided
std::invoke(std::forward<const llama_decode_callback>(callback_), new_token_id, is_eos);
// Next iteration
batch = llama_batch_get_one(&new_token_id, 1);
}
}
backlog.pop();
}
return n_decoded_tokens;
}
llama_free(context);
backend_base_t::backend_base_t(llama_model *model) : mModel_(model, llama_free_model) { llama_backend_init(); }
backend_base_t::~backend_base_t() { llama_backend_free(); }
std::expected<std::vector<llama_token>, backend_error_t> backend_base_t::generate(
std::span<const llama_token> tokens,
const generation_params_t &generation_params,
const sampling_params_t &sampling_params,
const std::optional<llama_decode_callback> &callback
) {
// TODO: Should we provide a way to change this value?
auto generated = std::vector<llama_token>(2 << 8);
auto nTokensGenerated = generate(tokens, generated, generation_params, sampling_params, callback);
if (nTokensGenerated.has_value())
generated.resize(*nTokensGenerated);
return generated;
}
huggingface::tgi::backends::llamacpp::BackendBase::BackendBase(llama_model *model)
: mModel_(model, llama_free_model) { llama_backend_init(); }
BackendBase::~BackendBase() { llama_backend_free(); }
/** Single worker_t Backend impl **/
single_worker_backend_t::single_worker_backend_t(llama_model *model,
const std::optional<llama_context_params> &params)
: backend_base_t(model),
mContext_(llama_context_factory(model)),
mWorker_(mModel_, params.value_or(llama_context_default_params())) {
llama_numa_init(ggml_numa_strategy::GGML_NUMA_STRATEGY_NUMACTL);
}
std::expected<std::size_t, backend_error_t>
single_worker_backend_t::generate(
std::span<const llama_token> tokens,
std::span<llama_token> out,
const generation_params_t &generation_params,
const sampling_params_t &sampling_params,
const std::optional<llama_decode_callback> &callback
) {
return mWorker_.generate(mContext_.get(), {generation_params, sampling_params, tokens, out}, callback);
}
}

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@ -8,25 +8,42 @@
#include <cmath>
#include <expected>
#include <filesystem>
#include <functional>
#include <queue>
#include <memory>
#include <optional>
#include <span>
#include <stop_token>
#include <vector>
#include <llama.h>
#include <thread>
#define LLAMA_SUCCESS(x) x == 0
namespace huggingface::tgi::backends::llamacpp {
enum BackendError : uint8_t {
static constexpr auto llama_context_deleter = [](llama_context *pContext) { llama_free(pContext); };
typedef std::unique_ptr<llama_context, decltype(llama_context_deleter)> llama_context_smart_ptr;
typedef std::function<void(llama_token, bool)> llama_decode_callback;
static constexpr auto llama_void_callback = [](llama_token token_id, bool is_eos) {};
/**
*
*/
enum backend_error_t : uint8_t {
MODEL_FILE_DOESNT_EXIST = 1
};
struct SamplingParams {
uint32_t topK = std::numeric_limits<decltype(topK)>::max();
float_t topP = 1.0f;
float_t frequencyPenalty = 0.0f;
float_t repetitionPenalty = 0.0f;
/**
*
*/
struct sampling_params_t {
uint32_t top_k = std::numeric_limits<decltype(top_k)>::max();
float_t top_p = 1.0f;
float_t frequency_penalty = 0.0f;
float_t repetition_penalty = 0.0f;
uint64_t seed = 2014;
/**
@ -34,38 +51,72 @@ namespace huggingface::tgi::backends::llamacpp {
* @param Pointer to the model data
* @return
*/
std::unique_ptr<llama_sampler> IntoLlamaSampler(const llama_model *) const;
std::unique_ptr<llama_sampler> into_llama_sampler(const llama_model *pModel) const;
};
class Worker {
/**
*
*/
struct generation_params_t {
uint32_t max_new_tokens = std::numeric_limits<uint32_t>::max();
};
struct generation_context_t {
generation_params_t generation_params;
sampling_params_t sampling_params;
std::span<const llama_token> input_tokens;
std::span<llama_token> generated_tokens;
};
/**
*
*/
class worker_t {
private:
const std::shared_ptr<llama_model> mModel_;
const llama_context_params mParams_;
public:
/**
*
* @param model
* @param params
*/
worker_t(std::shared_ptr<llama_model> model, const llama_context_params &params);
/**
*
* @param context
* @param generation_context
* @param callback
*/
size_t
generate(llama_context *, const generation_context_t &, const std::optional<llama_decode_callback> &) const;
/**
*
*/
void loop(std::stop_source &driver, std::queue<generation_context_t> &backlog) const;
};
class backend_base_t {
protected:
constexpr static auto llama_context_deleter = [](llama_context *pContext) { llama_free(pContext); };
public:
using model_ptr_type = std::shared_ptr<llama_model>;
using context_params_type = llama_context_params;
using token_id_type = llama_token;
private:
const model_ptr_type mModel_;
context_params_type mParams_;
public:
Worker(std::shared_ptr<llama_model> pModel, const llama_context_params &params);
void Loop(std::atomic_flag &, std::atomic_uint8_t &, std::queue<SamplingParams> &) const;
};
class BackendBase {
private:
std::shared_ptr<llama_model> mModel_;
public:
explicit BackendBase(llama_model *model);
~BackendBase();
/**
*
* @param model
*/
explicit backend_base_t(llama_model *model);
/**
* Destructor
*/
~backend_base_t();
/**
*
@ -76,12 +127,13 @@ namespace huggingface::tgi::backends::llamacpp {
* @return
*/
[[nodiscard("Generated tokens will be freed after this call if not assigned to an lvalue")]]
std::expected<std::vector<llama_token>, BackendError> Generate(
std::span<const llama_token> tokens,
std::span<llama_token> out,
const SamplingParams &params,
uint32_t maxNewTokens = std::numeric_limits<uint32_t>::max() - 1
);
virtual std::expected<size_t, backend_error_t> generate(
std::span<const llama_token> input_tokens,
std::span<llama_token> generated_tokens,
const generation_params_t &generation_params,
const sampling_params_t &sampling_params,
const std::optional<llama_decode_callback> &callback
) = 0;
/**
*
@ -91,12 +143,46 @@ namespace huggingface::tgi::backends::llamacpp {
* @return
*/
[[nodiscard("Generated tokens will be freed after this call if not assigned to an lvalue")]]
std::expected<std::vector<llama_token>, BackendError> Generate(
std::expected<std::vector<llama_token>, backend_error_t> generate(
std::span<const llama_token> tokens,
const SamplingParams &params,
uint32_t maxNewTokens = std::numeric_limits<uint32_t>::max() - 1
const generation_params_t &generation_params,
const sampling_params_t &sampling_params,
const std::optional<llama_decode_callback> &callback = std::nullopt
);
};
class single_worker_backend_t : backend_base_t {
private:
constexpr const static auto llama_context_factory = [](llama_model *pModel) -> llama_context_smart_ptr {
auto llParams = llama_context_default_params();
llParams.flash_attn = true;
llParams.n_batch = 1;
llParams.no_perf = true;
llParams.attention_type = llama_attention_type::LLAMA_ATTENTION_TYPE_CAUSAL;
return {llama_new_context_with_model(pModel, llParams), llama_context_deleter};
};
llama_context_smart_ptr mContext_;
worker_t mWorker_;
public:
explicit single_worker_backend_t(llama_model *pModel, const std::optional<llama_context_params> &);
using backend_base_t::generate;
std::expected<size_t, backend_error_t>
generate(
std::span<const llama_token> tokens,
std::span<llama_token> out,
const generation_params_t &generation_params,
const sampling_params_t &sampling_params,
const std::optional<llama_decode_callback> &callback
) override;
};
}
#endif //TGI_LLAMA_CPP_BACKEND_BACKEND_HPP