examples/finetune -opt SGD (stochastic gradient descent) memory opt

add unit tested GGML_OPT_OPTIMIZER_SGD to ggml - avoids allocating
m, v tensors.

support finetune.cpp arg -opt SGD (or sgd). (default adamw as before)

llama 3.2-1b-F32 result: observed 11gb gpu ram (41 sec/epoch)
when using SGD instead of 19gb (55 sec/epoch) using adamw.
(wikipedia 100 lines finetune)

(
using the same GPU memory, adamw can only do before OOM 512
batch/context, reaching:
train: [███████▉] data=0000140/0000140 loss=0.02575±0.00099 acc=99.52±0.03% t=00:00:47 ETA=00:00:00
val:   [███████▉] data=0000008/0000008 loss=4.76565±0.28810 acc=41.46±0.77% t=00:00:00 ETA=00:00:00

SGD is superior, though it converges slower, with max before OOM 1728
batch/context (esp see the better validation perf):
train: [███████▉] data=0000039/0000039 loss=0.00371±0.00010 acc=99.96±0.01% t=00:00:41 ETA=00:00:00
val:   [███████▉] data=0000003/0000003 loss=5.11406±0.76034 acc=48.01±0.69% t=00:00:01 ETA=00:00:00
)

note: when finetuning long enough (or w/ enough -lr),
validation accuracy *eventually* drops ('catastrophic forgetting')

-lr-half (halflife) option useful for SGD to avoid oscillation or
super slow underdamped learning (makes setting -lr more forgiving).
terminal -lr for now is set by lr-halvings i.e. if you want at most
1/8 the inital -lr you set -lr-halvings 3.

note: objective loss not directly comparable between adamw, sgd? -
check perplexity or accuracy or consider relative improvements
for convergence

new finetune args -wd 1e-9 to enable weight decay in sgd or adamw,
and max -epochs N (default 2 as before)

cache (1 - wd*alpha) in 'adamw' opt struct -
no noticeable perf benefit, disabled (still done
for new SGD though)

since opt. memory is pre-allocated, the ggml_opt_get_optimizer_params
would probably be able to change between SGD and AdamW with each epoch
but would need to use adamw for the first (unconfirmed - no cmdline arg
to set such a policy yet)

test-opt checks adamw as before and now sgd (except for a few disabled
tests for sgd only; probably just needs logging values and adding
alternate reference values);  tolerance on the 'regression'
test is broader for sgd (so we don't need many more epochs)

Author: graehl

CMakeLists.txt

@@ -12,6 +12,8 @@ if (NOT XCODE AND NOT MSVC AND NOT CMAKE_BUILD_TYPE)
     set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
 endif()
 
+message("CMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
+
 # Add path to modules
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/")
 

common/arg.cpp

@@ -1200,6 +1200,7 @@ bool common_params_parse(int argc, char ** argv, common_params & params, llama_e
             common_params_print_completion(ctx_arg);
             exit(0);
         }
+        params.lr.init();
     } catch (const std::invalid_argument & ex) {
         fprintf(stderr, "%s\n", ex.what());
         ctx_arg.params = params_org;
@@ -2613,9 +2614,9 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
         {"-o", "--output", "--output-file"}, "FNAME",
         string_format("output file (default: '%s')", params.out_file.c_str()),
         [](common_params & params, const std::string & value) {
-            params.out_file = value;
+          params.out_file = value;
         }
-    ).set_examples({LLAMA_EXAMPLE_IMATRIX, LLAMA_EXAMPLE_CVECTOR_GENERATOR, LLAMA_EXAMPLE_EXPORT_LORA, LLAMA_EXAMPLE_TTS}));
+    ).set_examples({LLAMA_EXAMPLE_IMATRIX, LLAMA_EXAMPLE_CVECTOR_GENERATOR, LLAMA_EXAMPLE_EXPORT_LORA, LLAMA_EXAMPLE_TTS, LLAMA_EXAMPLE_FINETUNE}));
     add_opt(common_arg(
         {"-ofreq", "--output-frequency"}, "N",
         string_format("output the imatrix every N iterations (default: %d)", params.n_out_freq),
@@ -3376,5 +3377,53 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
         }
     ).set_examples({LLAMA_EXAMPLE_SERVER}));
 
+    add_opt(
+        common_arg({ "-lr", "--learning-rate-initial" }, "ALPHA",
+                   string_format(
+                       "adamw or sgd optimizer alpha (default: %.2g); note: sgd alpha recommended ~10x (no momentum)",
+                       (double) params.lr.lr0),
+                   [](common_params & params, const std::string & value) { params.lr.lr0 = std::stof(value); })
+            .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+    add_opt(
+        common_arg({ "-lr-min", "--learning-rate-min" }, "ALPHA",
+                   string_format(
+                       "(if >0) final learning rate (default=%.2g)",
+                       (double) params.lr.lr_min),
+                   [](common_params & params, const std::string & value) { params.lr.lr_min = std::stof(value); })
+            .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+    add_opt(common_arg(
+                { "-lr-half", "--learning-rate-halflife" }, "N",
+                string_format("half-life (in epochs) for -lr (default: %.3g)", (double) params.lr.halflife_epochs),
+                [](common_params & params, const std::string & value) { params.lr.halflife_epochs = std::stof(value); })
+                .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+    add_opt(common_arg({ "-lr-halvings", "--learning-rate-halvings" }, "N",
+                       string_format("max N lr halvings (default: %.3g)", (double) params.lr.halvings),
+                       [](common_params & params, const std::string & value) { params.lr.halvings = std::stof(value); })
+                .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+    add_opt(common_arg(
+                { "-wd", "--weight-decay" }, "WD",
+                string_format(
+                    "adamw or sgd optimizer weight decay (0 is off; recommend very small e.g. 1e-9) (default: %.2g).",
+                    (double) params.lr.wd),
+                [](common_params & params, const std::string & value) { params.lr.wd = std::stof(value); })
+                .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+    add_opt(common_arg({ "-val", "--val-split" }, "FRACTION",
+                       string_format("fraction of data to use as validation set for training (default: %.2g).",
+                                     (double) params.val_split),
+                       [](common_params & params, const std::string & value) { params.val_split = std::stof(value); })
+                .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+    add_opt(common_arg({ "-epochs", "--epochs" }, "N",
+                       string_format("optimizer max # of epochs (default: %d)", params.lr.epochs),
+                       [](common_params & params, int epochs) { params.lr.epochs = epochs; })
+                .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+    add_opt(common_arg({ "-opt", "--optimizer" }, "sgd|adamw", "adamw or sgd",
+                       [](common_params & params, const std::string & name) {
+                           params.optimizer = common_opt_get_optimizer(name.c_str());
+                           if (params.optimizer == GGML_OPT_OPTIMIZER_TYPE_COUNT) {
+                               throw std::invalid_argument("invalid --optimizer, valid options: adamw, sgd");
+                           }
+                       })
+                .set_examples({ LLAMA_EXAMPLE_FINETUNE }));
+
     return ctx_arg;
 }

common/common.cpp

@@ -1535,3 +1535,21 @@ ggml_opt_dataset_t common_opt_dataset_init(struct llama_context * ctx, const std
 
     return result;
 }
+
+ggml_opt_optimizer_params common_opt_lr_pars(void * userdata) {
+    ggml_opt_optimizer_params result = ggml_opt_get_default_optimizer_params(nullptr);
+    const lr_opt &            d      = *(lr_opt *) userdata;
+    result.adamw.alpha = result.sgd.alpha = d.get_lr(d.epoch);
+    result.sgd.wd = result.adamw.wd = d.wd;
+    return result;
+}
+
+GGML_API enum ggml_opt_optimizer_type common_opt_get_optimizer(const char * n) {
+    if (!strcasecmp("adamw", n)) {
+        return GGML_OPT_OPTIMIZER_TYPE_ADAMW;
+    } else if (!strcasecmp("sgd", n)) {
+        return GGML_OPT_OPTIMIZER_TYPE_SGD;
+    } else {
+        return GGML_OPT_OPTIMIZER_TYPE_COUNT;
+    }
+}

common/common.h

@@ -2,13 +2,15 @@
 
 #pragma once
 
-#include "llama-cpp.h"
-
 #include <set>
+#include <sstream>
 #include <string>
 #include <string_view>
 #include <vector>
-#include <sstream>
+#include <cmath>
+
+#include "ggml-opt.h"
+#include "llama-cpp.h"
 
 #ifdef _WIN32
 #define DIRECTORY_SEPARATOR '\\'
@@ -80,6 +82,7 @@ enum llama_example {
     LLAMA_EXAMPLE_LOOKUP,
     LLAMA_EXAMPLE_PARALLEL,
     LLAMA_EXAMPLE_TTS,
+    LLAMA_EXAMPLE_FINETUNE,
 
     LLAMA_EXAMPLE_COUNT,
 };
@@ -219,6 +222,42 @@ enum common_reasoning_format {
     COMMON_REASONING_FORMAT_DEEPSEEK,        // Extract thinking tag contents and return as `message.reasoning_content`, including in streaming deltas.
 };
 
+
+static float constexpr k_log_2 = std::log(2.f);
+
+struct lr_opt {
+    float    lr0             = 1e-5; // learning rate at first epoch
+    float    lr_min          = 0;
+    float    min_epochs      = -1;  // if >0, constant (lr_min) after this many epochs
+    float    halflife_epochs = 100;
+    float    halvings        = 10;
+    float    epoch           = 0;
+    float    wd              = 0;
+    unsigned epochs          = 2;
+
+    float get_lr(float epoch) const {
+        float maxepoch = halvings * halflife_epochs;
+        return lr0 * std::pow(.5, (epoch > maxepoch ? maxepoch : epoch) / halflife_epochs);
+    }
+
+    void init() {
+        if (lr_min > 0 && lr_min < lr0) {
+            float nhalf = std::log(lr0 / lr_min) / k_log_2;
+            halvings    = nhalf;
+            float e     = epoch;
+            if (min_epochs > 0 && min_epochs < e)
+                e = min_epochs;
+            halflife_epochs = e / nhalf;
+        } else if (min_epochs > 0) {
+            float h = min_epochs / halflife_epochs;
+            if (h < halvings)
+                halvings = h;
+        }
+    }
+};
+
+struct ggml_opt_optimizer_params common_opt_lr_pars(void * userdata);
+
 struct common_params {
     int32_t n_predict             =    -1; // new tokens to predict
     int32_t n_ctx                 =  4096; // context size
@@ -350,6 +389,12 @@ struct common_params {
     bool no_mmproj = false;         // explicitly disable multimodal model
     std::vector<std::string> image; // path to image file(s)
 
+    // finetune
+    struct lr_opt lr;
+    enum ggml_opt_optimizer_type optimizer = GGML_OPT_OPTIMIZER_TYPE_ADAMW;
+    float val_split = 0.05f; // fraction of the data used for the validation set
+    std::string opt_save_model_to = "finetuned-model.gguf";
+
     // embedding
     bool embedding         = false; // get only sentence embedding
     int32_t embd_normalize = 2;     // normalisation for embeddings (-1=none, 0=max absolute int16, 1=taxicab, 2=euclidean, >2=p-norm)
@@ -671,3 +716,6 @@ const char * const LLM_KV_SPLIT_TENSORS_COUNT = "split.tensors.count";
 //
 
 ggml_opt_dataset_t common_opt_dataset_init(struct llama_context * ctx, const std::vector<llama_token> & tokens, int64_t stride);
+
+// "adamw" or "sgd" (case insensitive)
+enum ggml_opt_optimizer_type common_opt_get_optimizer(const char *);

examples/training/finetune.cpp

@@ -1,29 +1,31 @@
-#include "arg.h"
-#include "common.h"
-#include "log.h"
-#include "llama.h"
-
 #include <cmath>
 #include <cstdio>
 #include <cstring>
 #include <ctime>
 #include <vector>
 
+#include "arg.h"
+#include "common.h"
+#include "llama.h"
+#include "log.h"
+
 #if defined(_MSC_VER)
-#pragma warning(disable: 4244 4267) // possible loss of data
+#    pragma warning(disable : 4244 4267)  // possible loss of data
 #endif
 
+
+
 int main(int argc, char ** argv) {
     common_params params;
-
     params.escape = false;
 
-    if (!common_params_parse(argc, argv, params, LLAMA_EXAMPLE_PERPLEXITY)) {
+    if (!common_params_parse(argc, argv, params, LLAMA_EXAMPLE_FINETUNE)) {
         return 1;
     }
 
     if (params.use_mmap) {
-        LOG_INF("%s: force disabling memory mapping because it would result in-read-only pointers to the weights\n", __func__);
+        LOG_INF("%s: force disabling memory mapping because it would result in-read-only pointers to the weights\n",
+                __func__);
         params.use_mmap = false;
     }
     if (params.cache_type_k != GGML_TYPE_F32) {
@@ -38,11 +40,11 @@ int main(int argc, char ** argv) {
     common_init();
     llama_backend_init();
     llama_numa_init(params.numa);
-
     // load the model and apply lora adapter, if any
-    common_init_result llama_init = common_init_from_params(params);
-    llama_model_ptr   & model = llama_init.model;
-    llama_context_ptr & ctx   = llama_init.context;
+    common_init_result  llama_init = common_init_from_params(params);
+    llama_model_ptr &   model      = llama_init.model;
+    llama_context_ptr & ctx        = llama_init.context;
+    auto pctx = ctx.get();
 
     if (model == NULL) {
         LOG_ERR("%s: unable to load model\n", __func__);
@@ -55,31 +57,32 @@ int main(int argc, char ** argv) {
         LOG_INF("%s\n", common_params_get_system_info(params).c_str());
     }
 
-    constexpr float val_split = 0.05f;
-
-    std::vector<llama_token> tokens = common_tokenize(ctx.get(), params.prompt, true);
-    ggml_opt_dataset_t dataset = common_opt_dataset_init(ctx.get(), tokens, llama_n_ctx(ctx.get())/2);
-
-    struct ggml_opt_optimizer_params optimizer_params = ggml_opt_get_default_optimizer_params(nullptr);
-    optimizer_params.adamw.alpha = 1e-7f; // learning rate
-
-    struct llama_opt_params lopt_params {
-        /*n_ctx_train     =*/ 0,
-        /*param_filter    =*/ llama_opt_param_filter_all,
-        /*param_filter_ud =*/ nullptr,
-        /*get_opt_pars    =*/ ggml_opt_get_constant_optimizer_params,
-        /*get_opt_pars_ud =*/ &optimizer_params,
+    std::vector<llama_token> tokens  = common_tokenize(pctx, params.prompt, true);
+    ggml_opt_dataset_t       dataset = common_opt_dataset_init(pctx, tokens, llama_n_ctx(pctx) / 2);
+
+    struct lr_opt & lr = params.lr;
+    LOG_INF("-optimizer %s -lr0 %.2g -wd %.2g -lr-min %.2g -lr-half %.2g -epochs %d -period %.2g -val %.2g\n",
+            ggml_opt_optimizer_name(params.optimizer), (double) lr.lr0, (double) lr.wd, (double) lr.lr_min, (double) lr.halflife_epochs,
+            (unsigned) lr.epochs, (double) params.n_batch / params.n_ubatch, (double) params.val_split);
+
+    struct llama_opt_params lopt_params{
+        /*n_ctx_train     =*/0,
+        /*param_filter    =*/llama_opt_param_filter_all,
+        /*param_filter_ud =*/nullptr,
+        /*get_opt_pars    =*/common_opt_lr_pars,
+        /*get_opt_pars_ud =*/&params.lr,
+        /*optimizer_type  =*/params.optimizer,
     };
-    llama_opt_init(ctx.get(), model.get(), lopt_params);
+    llama_opt_init(pctx, model.get(), lopt_params);
 
-    const int64_t idata_split = ggml_opt_dataset_ndata(dataset) * (1.0f - val_split);
+    const int64_t idata_split = ggml_opt_dataset_ndata(dataset) * (1.0f - params.val_split);
 
     ggml_opt_result_t result_train = ggml_opt_result_init();
     ggml_opt_result_t result_eval  = ggml_opt_result_init();
 
-    for (int epoch = 0; epoch < 2; ++epoch) {
-        llama_opt_epoch(ctx.get(), dataset, result_train, result_eval, idata_split,
-            ggml_opt_epoch_callback_progress_bar, ggml_opt_epoch_callback_progress_bar);
+    for (unsigned epoch = 0; epoch < lr.epochs; ++epoch) {
+        llama_opt_epoch(pctx, dataset, result_train, result_eval, idata_split,
+                        ggml_opt_epoch_callback_progress_bar, ggml_opt_epoch_callback_progress_bar);
         fprintf(stderr, "\n");
 
         ggml_opt_result_reset(result_train);
@@ -88,7 +91,7 @@ int main(int argc, char ** argv) {
     ggml_opt_result_free(result_train);
     ggml_opt_result_free(result_eval);
 
-    llama_model_save_to_file(model.get(), "finetuned-model.gguf");
+    llama_model_save_to_file(model.get(), params.out_file.c_str());
 
     llama_backend_free();
 

ggml/include/ggml-opt.h

@@ -74,16 +74,26 @@ extern "C" {
         GGML_OPT_BUILD_TYPE_OPT     = 30,
     };
 
+    enum ggml_opt_optimizer_type {
+        GGML_OPT_OPTIMIZER_TYPE_ADAMW,
+        GGML_OPT_OPTIMIZER_TYPE_SGD,
+
+        GGML_OPT_OPTIMIZER_TYPE_COUNT
+    };
+
     // parameters that control which optimizer is used and how said optimizer tries to find the minimal loss
     struct ggml_opt_optimizer_params {
-        // AdamW optimizer parameters
         struct {
-            float alpha; // learning rate
-            float beta1;
-            float beta2;
-            float eps;   // epsilon for numerical stability
-            float wd;    // weight decay for AdamW, use 0.0f to disable
+            float alpha;  // learning rate
+            float beta1;  // first AdamW momentum
+            float beta2;  // second AdamW momentum
+            float eps;    // epsilon for numerical stability
+            float wd;     // weight decay - 0.0f to disable
         } adamw;
+        struct {
+            float alpha; // learning rate
+            float wd; // weight decay
+        } sgd;
     };
 
     // callback to calculate optimizer parameters prior to a backward pass
@@ -113,7 +123,10 @@ extern "C" {
         int32_t opt_period; // after how many gradient accumulation steps an optimizer step should be done
 
         ggml_opt_get_optimizer_params get_opt_pars; // callback for calculating optimizer parameters
-        void * get_opt_pars_ud;                     // userdata for calculating optimizer parameters
+        void *                        get_opt_pars_ud;  // userdata for calculating optimizer parameters
+
+        // only GGML_OPT_OPTIMIZER_TYPE_ADAMW allocates m, v per parameter
+        enum ggml_opt_optimizer_type optimizer;
     };
 
     // get parameters for an optimization context with defaults set where possible
@@ -142,6 +155,10 @@ extern "C" {
     // get the gradient accumulator for a node from the forward graph
     GGML_API struct ggml_tensor * ggml_opt_grad_acc(ggml_opt_context_t opt_ctx, struct ggml_tensor * node);
 
+    GGML_API enum ggml_opt_optimizer_type ggml_opt_context_optimizer_type(ggml_opt_context_t);
+
+    GGML_API const char * ggml_opt_optimizer_name(enum ggml_opt_optimizer_type);
+
     // ====== Optimization Result ======
 
     GGML_API ggml_opt_result_t ggml_opt_result_init(void);
@@ -226,12 +243,14 @@ extern "C" {
             struct ggml_tensor            * outputs,        // output tensor, must have shape [ne_label, ndata_batch] if labels are used
             ggml_opt_dataset_t              dataset,        // dataset with data and optionally also labels
             enum ggml_opt_loss_type         loss_type,      // loss to minimize
+            enum ggml_opt_optimizer_type    optimizer,      // sgd or adamw
             ggml_opt_get_optimizer_params   get_opt_pars,   // callback to get optimizer params, userdata is pointer to epoch (of type int64_t)
             int64_t                         nepoch,         // how many times the dataset should be iterated over
             int64_t                         nbatch_logical, // datapoints optimizer step, must be a multiple of ndata_batch in inputs/outputs
             float                           val_split,      // fraction of the dataset to use for validation, must be in [0.0f, 1.0f)
             bool                            silent);        // whether or not info prints to stderr should be suppressed
 
+
 #ifdef  __cplusplus
 }
 #endif