Rewrite loading code to try to satisfy everyone

Features:

- Support all three formats (ggml, ggmf, ggjt).  (However, I didn't
  include the hack needed to support GPT4All files without conversion.
  Those can still be used after converting them with convert.py from my
  other PR.)

- Support both mmap and read (mmap is used by default, but can be
  disabled with `--no-mmap`, and is automatically disabled for pre-ggjt
  files or on platforms where mmap is not supported).

- Support multi-file models like before, but automatically determine the
  number of parts rather than requiring `--n_parts`.

- Improve validation and error checking.

- Stop using the per-file type field (f16) entirely in favor of just
  relying on the per-tensor type/size fields.  This has no immediate
  benefit, but makes it easier to experiment with different formats, and
  should make it easier to support the new GPTQ-for-LLaMa models in the
  future (I have some work in progress on that front).

- Support VirtualLock on Windows (using the same `--mlock` option as on
  Unix).

- madvise/PrefetchVirtualMemory support (based on ggerganov#740)

- Switch from ifstream to the `fopen` family of functions to avoid
  unnecessary copying and, when mmap is enabled, allow reusing the same
  file descriptor for both metadata reads and mmap (whereas the existing
  implementation opens the file a second time to mmap).

- Quantization now produces a single-file output even with multi-file
  inputs (not really a feature as much as 'it was easier this way').

Todo:

- **VirtualLock does not work at all** on the one Windows machine I tested
  it on (it complains about quota).  Figure out why.

- Verify that using the `fopen` family of functions actually does what I
  think it does, performance-wise.

- More testing.

Implementation notes:

I tried to factor the code into more discrete pieces than before.

Regarding code style: I tried to follow the code style, but I'm naughty and
used a few advanced C++ features repeatedly:

- Destructors to make it easier to ensure everything gets cleaned up.

- Exceptions.  I don't even usually use exceptions when writing C++, and
  I can remove them if desired... but here they make the loading code
  much more succinct while still properly handling a variety of errors,
  ranging from API calls failing to integer overflow and allocation
  failure.

Co-authored-by: Pavol Rusnak <pavol@rusnak.io> (for the bit I copied from ggerganov#740)

examples/common.cpp

@@ -1,7 +1,5 @@
 #include "common.h"
 
-#include "ggml.h"
-
 #include <cassert>
 #include <cstring>
 #include <fstream>
@@ -154,6 +152,8 @@ bool gpt_params_parse(int argc, char ** argv, gpt_params & params) {
             params.use_color = true;
         } else if (arg == "--mlock") {
             params.use_mlock = true;
+        } else if (arg == "--no-mmap") {
+            params.use_mmap = false;
         } else if (arg == "--mtest") {
             params.mem_test = true;
         } else if (arg == "--verbose-prompt") {
@@ -233,9 +233,12 @@ void gpt_print_usage(int /*argc*/, char ** argv, const gpt_params & params) {
     fprintf(stderr, "  -b N, --batch_size N  batch size for prompt processing (default: %d)\n", params.n_batch);
     fprintf(stderr, "  --perplexity          compute perplexity over the prompt\n");
     fprintf(stderr, "  --keep                number of tokens to keep from the initial prompt (default: %d, -1 = all)\n", params.n_keep);
-    if (ggml_mlock_supported()) {
+    if (llama_mlock_supported()) {
         fprintf(stderr, "  --mlock               force system to keep model in RAM rather than swapping or compressing\n");
     }
+    if (llama_mmap_supported()) {
+        fprintf(stderr, "  --no-mmap             do not memory-map model (slower load but may reduce pageouts if not using mlock)\n");
+    }
     fprintf(stderr, "  --mtest               compute maximum memory usage\n");
     fprintf(stderr, "  --verbose-prompt      print prompt before generation\n");
     fprintf(stderr, "  -m FNAME, --model FNAME\n");

examples/common.h

@@ -47,6 +47,7 @@ struct gpt_params {
     bool instruct          = false; // instruction mode (used for Alpaca models)
     bool ignore_eos        = false; // do not stop generating after eos
     bool perplexity        = false; // compute perplexity over the prompt
+    bool use_mmap          = true;  // use mmap for faster loads
     bool use_mlock         = false; // use mlock to keep model in memory
     bool mem_test          = false; // compute maximum memory usage
     bool verbose_prompt    = false; // print prompt tokens before generation

examples/embedding/embedding.cpp

@@ -38,6 +38,7 @@ int main(int argc, char ** argv) {
         lparams.seed       = params.seed;
         lparams.f16_kv     = params.memory_f16;
         lparams.logits_all = params.perplexity;
+        lparams.use_mmap   = params.use_mmap;
         lparams.use_mlock  = params.use_mlock;
         lparams.embedding  = params.embedding;
 

examples/main/main.cpp

@@ -97,6 +97,7 @@ int main(int argc, char ** argv) {
         lparams.n_parts    = params.n_parts;
         lparams.seed       = params.seed;
         lparams.f16_kv     = params.memory_f16;
+        lparams.use_mmap   = params.use_mmap;
         lparams.use_mlock  = params.use_mlock;
 
         ctx = llama_init_from_file(params.model.c_str(), lparams);

examples/perplexity/perplexity.cpp

@@ -115,6 +115,7 @@ int main(int argc, char ** argv) {
         lparams.seed       = params.seed;
         lparams.f16_kv     = params.memory_f16;
         lparams.logits_all = params.perplexity;
+        lparams.use_mmap   = params.use_mmap;
         lparams.use_mlock  = params.use_mlock;
         lparams.embedding  = params.embedding;
 

ggml.c

@@ -97,17 +97,6 @@ typedef void* thread_ret_t;
 #define static_assert(cond, msg) _Static_assert(cond, msg)
 #endif
 
-#define GGML_MLOCK_SUPPORT 0
-
-#ifdef __has_include
-    #if __has_include(<sys/mman.h>)
-        #undef GGML_MLOCK_SUPPORT
-        #define GGML_MLOCK_SUPPORT 1
-        #include <sys/mman.h>
-    #endif
-#endif
-
-
 /*#define GGML_PERF*/
 #define GGML_DEBUG 0
 #define GGML_GELU_FP16
@@ -2690,21 +2679,6 @@ static const char * GGML_OP_SYMBOL[GGML_OP_COUNT] = {
 
 static_assert(GGML_OP_COUNT == 35, "GGML_OP_COUNT != 35");
 
-//
-// ggml object
-//
-
-struct ggml_object {
-    size_t offs;
-    size_t size;
-
-    struct ggml_object * next;
-
-    char padding[8];
-};
-
-static const size_t GGML_OBJECT_SIZE = sizeof(struct ggml_object);
-
 static_assert(sizeof(struct ggml_object)%GGML_MEM_ALIGN == 0, "ggml_object size must be a multiple of GGML_MEM_ALIGN");
 static_assert(sizeof(struct ggml_tensor)%GGML_MEM_ALIGN == 0, "ggml_tensor size must be a multiple of GGML_MEM_ALIGN");
 
@@ -2716,7 +2690,6 @@ struct ggml_context {
     size_t mem_size;
     void * mem_buffer;
     bool   mem_buffer_owned;
-    bool   mem_buffer_mlocked;
     bool   no_alloc;
 
     int    n_objects;
@@ -3003,7 +2976,6 @@ struct ggml_context * ggml_init(struct ggml_init_params params) {
         /*.mem_size           =*/ params.mem_size,
         /*.mem_buffer         =*/ params.mem_buffer ? params.mem_buffer : malloc(params.mem_size),
         /*.mem_buffer_owned   =*/ params.mem_buffer ? false : true,
-        /*.mem_buffer_mlocked =*/ false,
         /*.no_alloc           =*/ params.no_alloc,
         /*.n_objects          =*/ 0,
         /*.objects_begin      =*/ NULL,
@@ -3036,14 +3008,6 @@ void ggml_free(struct ggml_context * ctx) {
             GGML_PRINT_DEBUG("%s: context %d with %d objects has been freed. memory used = %zu\n",
                     __func__, i, ctx->n_objects, ctx->objects_end->offs + ctx->objects_end->size);
 
-#if GGML_MLOCK_SUPPORT
-            if (ctx->mem_buffer_mlocked) {
-                if (munlock(ctx->mem_buffer, ctx->mem_size)) {
-                    fprintf(stderr, "%s: failed to munlock buffer: %s\n", __func__, strerror(errno));
-                }
-            }
-#endif
-
             if (ctx->mem_buffer_owned) {
                 free(ctx->mem_buffer);
             }
@@ -3072,48 +3036,6 @@ size_t ggml_set_scratch(struct ggml_context * ctx, struct ggml_scratch scratch)
     return result;
 }
 
-#ifdef __APPLE__
-#define MLOCK_SUGGESTION \
-    "Try increasing the sysctl values 'vm.user_wire_limit' and 'vm.global_user_wire_limit' and/or " \
-    "decreasing 'vm.global_no_user_wire_amount'.  Also try increasing RLIMIT_MLOCK (ulimit -l).\n"
-#else
-#define MLOCK_SUGGESTION \
-    "Try increasing RLIMIT_MLOCK ('ulimit -l' as root).\n"
-#endif
-
-bool ggml_mlock_supported(void) {
-    return GGML_MLOCK_SUPPORT;
-}
-
-bool ggml_mlock(
-        struct ggml_context * ctx,
-        const void *opt_extra_addr,
-        size_t opt_extra_len,
-        char **err_p) {
-    // TODO: Use SetProcessWorkingSetSize() + VirtualLock() on WIN32
-#if GGML_MLOCK_SUPPORT
-    if (ctx->mem_buffer_mlocked) {
-        return true;
-    }
-    if (mlock(ctx->mem_buffer, ctx->mem_size) ||
-        (opt_extra_len &&
-         mlock(opt_extra_addr, opt_extra_len))) {
-        if ((*err_p = malloc(1024))) {
-            snprintf(*err_p, 1024,
-                     "failed to mlock %zu-byte buffer: %s\n" MLOCK_SUGGESTION,
-                     ctx->mem_size + opt_extra_len,
-                     strerror(errno));
-        }
-        return false;
-    }
-    ctx->mem_buffer_mlocked = true;
-    return true;
-#else // GGML_MLOCK_SUPPORT
-    *err_p = strdup("can't mlock because it's not supported on this system");
-    return false;
-#endif // GGML_MLOCK_SUPPORT
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 
 struct ggml_tensor * ggml_new_tensor_impl(

ggml.h

@@ -253,6 +253,19 @@ enum ggml_op {
     GGML_OP_COUNT,
 };
 
+
+// ggml object
+struct ggml_object {
+    size_t offs;
+    size_t size;
+
+    struct ggml_object * next;
+
+    char padding[8];
+};
+
+static const size_t GGML_OBJECT_SIZE = sizeof(struct ggml_object);
+
 // n-dimensional tensor
 struct ggml_tensor {
     enum ggml_type type;
@@ -344,13 +357,6 @@ size_t ggml_used_mem(const struct ggml_context * ctx);
 
 size_t ggml_set_scratch(struct ggml_context * ctx, struct ggml_scratch scratch);
 
-bool ggml_mlock_supported(void);
-bool ggml_mlock(
-        struct ggml_context * ctx,
-        const void *opt_extra_addr,
-        size_t opt_extra_len,
-        char **err_p);
-
 struct ggml_tensor * ggml_new_tensor(
         struct ggml_context * ctx,
         enum   ggml_type type,