Use aligned_alloc() if aligned allocations are required

[Rhialto]

Prerequisites

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• I am running the latest code. Development is very rapid so there are no tagged versions as of now.
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Expected Behavior

quantize should run and not abort with an assertion failure

Current Behavior

GGML_ASSERT: ggml.c:2990: ((uintptr_t) (ctx->mem_buffer))%GGML_MEM_ALIGN == 0
Abort trap (core dumped)

Environment and Context

• Operating System

NetBSD 9.3

Failure Information (for bugs)

The memory allocated by malloc is alingned to 8, not 16 (GGML_MEM_ALIGN)

Fix:

diff --git a/ggml.c b/ggml.c
index 326b8e8..efa3f15 100644
--- a/ggml.c
+++ b/ggml.c
@@ -2974,7 +2974,7 @@ struct ggml_context * ggml_init(struct ggml_init_params params) {
 
     *ctx = (struct ggml_context) {
         /*.mem_size           =*/ params.mem_size,
-        /*.mem_buffer         =*/ params.mem_buffer ? params.mem_buffer : malloc(params.mem_size),
+        /*.mem_buffer         =*/ params.mem_buffer ? params.mem_buffer : aligned_alloc(GGML_MEM_ALIGN , params.mem_size),
         /*.mem_buffer_owned   =*/ params.mem_buffer ? false : true,
         /*.no_alloc           =*/ params.no_alloc,
         /*.n_objects          =*/ 0,

[prusnak]

The proposed fix does not work on Windows (MSVC), since it does not implement aligned_alloc.

[j-f1]

Specifically, you’d need to use _aligned_malloc on Windows, and then make sure to use _aligned_free to free the buffer, also making sure to use _aligned_realloc if realloc is ever used.

[prusnak]

Specifically, you’d need to use ...

Thanks! Created #884

@Rhialto can you please check this fixes the issue for you?

[Rhialto]

@prusnak Yes thanks! That works for me!