llama : add custom RoPE (#2054)

* Implement customizable RoPE

The original RoPE has pre-defined parameters

theta_i = 10000^(−2(i−1)/d), for i in [1, 2, ..., d/2]

Our customizable RoPE, ggml_rope_custom_inplace, uses

theta_i = scale * base^(−2(i−1)/d), for i in [1, 2, ..., d/2]

with the default matches the original

scale = 1.0
base = 10000

The new command line arguments
--rope-freq-base
--rope-freq-scale
set the two new RoPE parameter.

Recent researches show changing these two parameters extends the context limit with minimal loss.

1. Extending Context to 8K
   kaiokendev
   https://kaiokendev.github.io/til#extending-context-to-8k

2. Extending Context Window of Large Language Models via Positional Interpolation
   Shouyuan Chen, Sherman Wong, Liangjian Chen, Yuandong Tian
   https://arxiv.org/abs/2306.15595

3. NTK-Aware Scaled RoPE allows LLaMA models to have extended (8k+) context size without any fine-tuning and minimal perplexity degradation.
   https://www.reddit.com/user/bloc97
   https://www.reddit.com/r/LocalLLaMA/comments/14lz7j5/ntkaware_scaled_rope_allows_llama_models_to_have/

For the bold, try adding the following command line parameters to your favorite model:
-c 16384 --rope-freq-base 80000 --rope-freq-scale 0.5

* ggml-metal: fix custom rope

* common: fix argument names in help

* llama: increase MEM_REQ_EVAL for MODEL_3B

It avoids crashing for quantized weights on CPU.
Better ways to calculate the required buffer size would be better.

* llama: make MEM_REQ_EVAL depend on n_ctx

* server: use proper Content-Type in curl examples

Without the header Content-Type: application/json, curl will POST with
Content-Type: application/x-www-form-urlencoded

Though our simple server doesn't care, the httplib.h used has a limit
with CPPHTTPLIB_FORM_URL_ENCODED_PAYLOAD_MAX_LENGTH 8192

With Content-Type: application/json, we can send large json data.

* style : minor fixes, mostly indentations

* ggml : fix asserts

---------

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

1 files changed, 26 insertions, 19 deletions

diff --git a/ggml-metal.m b/ggml-metal.m
index c795ee2..ee205bc 100644
--- a/ggml-metal.m
+++ b/ggml-metal.m
@@ -881,28 +881,35 @@ void ggml_metal_graph_compute(
 
                             const int n_past = ((int32_t *)(src1->data))[0];
 
+                            float freq_base;
+                            float freq_scale;
+                            memcpy(&freq_base,  (int32_t *) src1->data + 4, sizeof(float));
+                            memcpy(&freq_scale, (int32_t *) src1->data + 5, sizeof(float));
+
                             [encoder setComputePipelineState:ctx->pipeline_rope];
                             [encoder setBuffer:id_src0 offset:offs_src0 atIndex:0];
                             [encoder setBuffer:id_dst  offset:offs_dst  atIndex:1];
-                            [encoder setBytes:&ne00   length:sizeof( int64_t) atIndex:2];
-                            [encoder setBytes:&ne01   length:sizeof( int64_t) atIndex:3];
-                            [encoder setBytes:&ne02   length:sizeof( int64_t) atIndex:4];
-                            [encoder setBytes:&ne03   length:sizeof( int64_t) atIndex:5];
-                            [encoder setBytes:&nb00   length:sizeof(uint64_t) atIndex:6];
-                            [encoder setBytes:&nb01   length:sizeof(uint64_t) atIndex:7];
-                            [encoder setBytes:&nb02   length:sizeof(uint64_t) atIndex:8];
-                            [encoder setBytes:&nb03   length:sizeof(uint64_t) atIndex:9];
-                            [encoder setBytes:&ne0    length:sizeof( int64_t) atIndex:10];
-                            [encoder setBytes:&ne1    length:sizeof( int64_t) atIndex:11];
-                            [encoder setBytes:&ne2    length:sizeof( int64_t) atIndex:12];
-                            [encoder setBytes:&ne3    length:sizeof( int64_t) atIndex:13];
-                            [encoder setBytes:&nb0    length:sizeof(uint64_t) atIndex:14];
-                            [encoder setBytes:&nb1    length:sizeof(uint64_t) atIndex:15];
-                            [encoder setBytes:&nb2    length:sizeof(uint64_t) atIndex:16];
-                            [encoder setBytes:&nb3    length:sizeof(uint64_t) atIndex:17];
-                            [encoder setBytes:&n_past length:sizeof(     int) atIndex:18];
-                            [encoder setBytes:&n_dims length:sizeof(     int) atIndex:19];
-                            [encoder setBytes:&mode   length:sizeof(     int) atIndex:20];
+                            [encoder setBytes:&ne00    length:sizeof( int64_t) atIndex:2];
+                            [encoder setBytes:&ne01    length:sizeof( int64_t) atIndex:3];
+                            [encoder setBytes:&ne02    length:sizeof( int64_t) atIndex:4];
+                            [encoder setBytes:&ne03    length:sizeof( int64_t) atIndex:5];
+                            [encoder setBytes:&nb00    length:sizeof(uint64_t) atIndex:6];
+                            [encoder setBytes:&nb01    length:sizeof(uint64_t) atIndex:7];
+                            [encoder setBytes:&nb02    length:sizeof(uint64_t) atIndex:8];
+                            [encoder setBytes:&nb03    length:sizeof(uint64_t) atIndex:9];
+                            [encoder setBytes:&ne0     length:sizeof( int64_t) atIndex:10];
+                            [encoder setBytes:&ne1     length:sizeof( int64_t) atIndex:11];
+                            [encoder setBytes:&ne2     length:sizeof( int64_t) atIndex:12];
+                            [encoder setBytes:&ne3     length:sizeof( int64_t) atIndex:13];
+                            [encoder setBytes:&nb0     length:sizeof(uint64_t) atIndex:14];
+                            [encoder setBytes:&nb1     length:sizeof(uint64_t) atIndex:15];
+                            [encoder setBytes:&nb2     length:sizeof(uint64_t) atIndex:16];
+                            [encoder setBytes:&nb3     length:sizeof(uint64_t) atIndex:17];
+                            [encoder setBytes:&n_past  length:sizeof(     int) atIndex:18];
+                            [encoder setBytes:&n_dims  length:sizeof(     int) atIndex:19];
+                            [encoder setBytes:&mode    length:sizeof(     int) atIndex:20];
+                            [encoder setBytes:&freq_base  length:sizeof(float) atIndex:21];
+                            [encoder setBytes:&freq_scale length:sizeof(float) atIndex:22];
 
                             [encoder dispatchThreadgroups:MTLSizeMake(ne01, ne02, ne03) threadsPerThreadgroup:MTLSizeMake(1, 1, 1)];
                         } break;