ggml: backend-agnostic tensor parallelism (experimental) (#19378)

* ggml: backend-agnostic tensor parallelism

* support for GPT-OSS, Qwen 3 MoE

* partial Vulkan fix

* add support for 4/8 GPUs

* unconditional peer access

* re-use buffers + ggml contexts

* fix output pattern

* NCCL support

* GGML: HIP: add RCCL support

* Remove shfl and AllReduce from backend interface

* move allocation workaround out of ggml-alloc.c

* 2d tensor set/get support

* Fix the seg fault without NCCL

* Apply suggestion from JohannesGaessler

* support for tensor dims % n_devs != 0

* fix view_offs scaling

* arbitrary num. of GPUs/tensor split

* fix compilation

* better granularity estimate

* Support device-specific host buffer types if all underlying backends expose the same type. This allows using pinned memory instead of pageable memory for CUDA.

Fix compilation errors.

* partial Qwen 3 Next support

* Fix qwen3 30b (#8)

* Fix crash with Qwen-30B-A3B Q4_0

Qwen-30B-A3B Q4_0 has an intermediate dimension of 768. Using a granularity of 256 forces an uneven split between GPUs, which is not supported by the current implementation.

* Decide block size based on tensor quantization type

* Fix crashes due to KV cache serialization (#9)

KV cache serialization requires non-zero offsets on the tensor. Add support in the meta backend to set/get a tensor with a non-zero offset.

* metal : fix build (#7)

* static memory allocations, fix usage count

* fix tensor granularity

* more even memory distribution

* use BF16 for allreduce

* rebase fixup

* better error message for unsupported architectures

* Fix device mismatch during scatter of allReduce. (#11)

There is a mismatch between the dst buffer device and the backend device, causing the use of sync copies

* Enable the previous allreduce implementation. It is better in both perf and stability (#12)

* delay AllReduce for Moe for less I/O

* build : clean-up compile warnings

* backend : move most of the meta backend API to ggml-backend-impl.h

* cont : hide unused public API in the implementation

* llama : use llama_device + remove ggml_backend_dev_is_meta()

* ggml-backend : remove unused alloc include

* minor : remove regex include

* ggml : introduce ggml-ext.h for staging new APIs

* rebase fixup

* fix tests

* llama : more robust logic for determining Meta devices (#16)

* llama : more robust logic for determining Meta devices

* cont : fix devs size check

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>

* cont : fix log type

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>

---------

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>

* disable roundtrip for meta backend

* fix arch selection

* Qwen 3.5 support

* fix Gemma 4 MoE

* fix OpenVino, SYCL

* fix test-llama-archs for CPU-only builds

* Fix Qwen 3.5 MoE

* disable meta backend tests for WebGPU

* tests : filter CPU-based devices from the Meta backend tests (#17)

* meta : formatting, naming, indentation (#18)

* formatting : llama-model.cpp

* formatting : ggml-ext.h

* formatting : ggml-backend-meta.cpp

* meta : add TODO

* add documentation

* better error messages

* fix GPT-OSS

---------

Co-authored-by: Carl Philipp Klemm <carl@uvos.xyz>
Co-authored-by: Gaurav Garg <gaugarg@nvidia.com>
Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
This commit is contained in:
Johannes Gäßler
2026-04-09 16:42:19 +02:00
committed by GitHub
parent 009a113326
commit d6f3030047
48 changed files with 3198 additions and 342 deletions
+102 -8
View File
@@ -123,7 +123,7 @@ size_t ggml_backend_buffer_get_size(ggml_backend_buffer_t buffer) {
void * ggml_backend_buffer_get_base(ggml_backend_buffer_t buffer) {
GGML_ASSERT(buffer);
// get_base is optional if the buffer is zero-sized
if (buffer->size == 0) {
if (!ggml_backend_buffer_is_meta(buffer) && buffer->size == 0) {
return NULL;
}
@@ -279,15 +279,57 @@ void ggml_backend_tensor_get_async(ggml_backend_t backend, const struct ggml_ten
}
}
void ggml_backend_tensor_set_2d_async(ggml_backend_t backend, struct ggml_tensor * tensor, const void * data, size_t offset, size_t size,
size_t n_copies, size_t stride_tensor, size_t stride_data) {
GGML_ASSERT(backend);
GGML_ASSERT(tensor);
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
if (n_copies <= 1 || backend->iface.set_tensor_2d_async == NULL) {
for (size_t i = 0; i < n_copies; i++) {
ggml_backend_tensor_set_async(backend, tensor, (const char *) data + i*stride_data, offset + i*stride_tensor, size);
}
return;
}
if (size == 0) {
return;
}
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
GGML_ASSERT(offset + (n_copies-1)*stride_tensor + size <= ggml_nbytes(tensor) && "tensor write out of bounds");
backend->iface.set_tensor_2d_async(backend, tensor, data, offset, size, n_copies, stride_tensor, stride_data);
}
void ggml_backend_tensor_get_2d_async(ggml_backend_t backend, const struct ggml_tensor * tensor, void * data, size_t offset, size_t size,
size_t n_copies, size_t stride_tensor, size_t stride_data) {
GGML_ASSERT(backend);
GGML_ASSERT(tensor);
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
if (n_copies <= 1 || backend->iface.set_tensor_2d_async == NULL) {
for (size_t i = 0; i < n_copies; i++) {
ggml_backend_tensor_get_async(backend, tensor, (char *) data + i*stride_data, offset + i*stride_tensor, size);
}
return;
}
if (size == 0) {
return;
}
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
GGML_ASSERT(offset + (n_copies-1)*stride_tensor + size <= ggml_nbytes(tensor) && "tensor write out of bounds");
backend->iface.get_tensor_2d_async(backend, tensor, data, offset, size, n_copies, stride_tensor, stride_data);
}
void ggml_backend_tensor_set(struct ggml_tensor * tensor, const void * data, size_t offset, size_t size) {
GGML_ASSERT(tensor);
ggml_backend_buffer_t buf = tensor->view_src ? tensor->view_src->buffer : tensor->buffer;
GGML_ASSERT(buf != NULL && "tensor buffer not set");
if (size == 0) {
return;
}
GGML_ASSERT(buf != NULL && "tensor buffer not set");
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
GGML_ASSERT(offset + size <= ggml_nbytes(tensor) && "tensor write out of bounds");
@@ -297,18 +339,62 @@ void ggml_backend_tensor_set(struct ggml_tensor * tensor, const void * data, siz
void ggml_backend_tensor_get(const struct ggml_tensor * tensor, void * data, size_t offset, size_t size) {
GGML_ASSERT(tensor);
ggml_backend_buffer_t buf = tensor->view_src ? tensor->view_src->buffer : tensor->buffer;
GGML_ASSERT(buf != NULL && "tensor buffer not set");
if (size == 0) {
return;
}
GGML_ASSERT(buf != NULL && "tensor buffer not set");
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
GGML_ASSERT(offset + size <= ggml_nbytes(tensor) && "tensor read out of bounds");
buf->iface.get_tensor(buf, tensor, data, offset, size);
}
void ggml_backend_tensor_set_2d(struct ggml_tensor * tensor, const void * data, size_t offset, size_t size,
size_t n_copies, size_t stride_tensor, size_t stride_data) {
GGML_ASSERT(tensor);
ggml_backend_buffer_t buf = tensor->view_src ? tensor->view_src->buffer : tensor->buffer;
GGML_ASSERT(buf != NULL && "tensor buffer not set");
if (n_copies <= 1 || buf->iface.set_tensor_2d == NULL) {
for (size_t i = 0; i < n_copies; i++) {
ggml_backend_tensor_set(tensor, (const char *) data + i*stride_data, offset + i*stride_tensor, size);
}
return;
}
if (size == 0) {
return;
}
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
GGML_ASSERT(offset + (n_copies-1)*stride_tensor + size <= ggml_nbytes(tensor) && "tensor write out of bounds");
buf->iface.set_tensor_2d(buf, tensor, data, offset, size, n_copies, stride_tensor, stride_data);
}
void ggml_backend_tensor_get_2d(const struct ggml_tensor * tensor, void * data, size_t offset, size_t size,
size_t n_copies, size_t stride_tensor, size_t stride_data) {
GGML_ASSERT(tensor);
ggml_backend_buffer_t buf = tensor->view_src ? tensor->view_src->buffer : tensor->buffer;
GGML_ASSERT(buf != NULL && "tensor buffer not set");
if (n_copies <= 1 || buf->iface.set_tensor_2d == NULL) {
for (size_t i = 0; i < n_copies; i++) {
ggml_backend_tensor_get(tensor, (char *) data + i*stride_data, offset + i*stride_tensor, size);
}
return;
}
if (size == 0) {
return;
}
GGML_ASSERT(tensor->data != NULL && "tensor not allocated");
GGML_ASSERT(offset + (n_copies-1)*stride_tensor + size <= ggml_nbytes(tensor) && "tensor read out of bounds");
buf->iface.get_tensor_2d(buf, tensor, data, offset, size, n_copies, stride_tensor, stride_data);
}
void ggml_backend_tensor_memset(struct ggml_tensor * tensor, uint8_t value, size_t offset, size_t size) {
GGML_ASSERT(tensor);
ggml_backend_buffer_t buf = tensor->view_src ? tensor->view_src->buffer : tensor->buffer;
@@ -388,7 +474,7 @@ ggml_backend_dev_t ggml_backend_get_device(ggml_backend_t backend) {
// backend copy
void ggml_backend_tensor_copy(struct ggml_tensor * src, struct ggml_tensor * dst) {
void ggml_backend_tensor_copy(const struct ggml_tensor * src, struct ggml_tensor * dst) {
GGML_ASSERT(ggml_are_same_layout(src, dst) && "cannot copy tensors with different layouts");
if (src == dst) {
@@ -402,7 +488,7 @@ void ggml_backend_tensor_copy(struct ggml_tensor * src, struct ggml_tensor * dst
} else if (!ggml_backend_buffer_copy_tensor(src, dst)) {
#ifndef NDEBUG
GGML_LOG_DEBUG("%s: warning: slow copy from %s to %s\n", __func__, ggml_backend_buffer_name(src->buffer), ggml_backend_buffer_name(dst->buffer));
#endif
#endif // NDEBUG
size_t nbytes = ggml_nbytes(src);
void * data = malloc(nbytes);
ggml_backend_tensor_get(src, data, 0, nbytes);
@@ -411,7 +497,7 @@ void ggml_backend_tensor_copy(struct ggml_tensor * src, struct ggml_tensor * dst
}
}
void ggml_backend_tensor_copy_async(ggml_backend_t backend_src, ggml_backend_t backend_dst, struct ggml_tensor * src, struct ggml_tensor * dst) {
void ggml_backend_tensor_copy_async(ggml_backend_t backend_src, ggml_backend_t backend_dst, const struct ggml_tensor * src, struct ggml_tensor * dst) {
GGML_ASSERT(ggml_are_same_layout(src, dst) && "cannot copy tensors with different layouts");
if (src == dst) {
@@ -500,6 +586,7 @@ enum ggml_backend_dev_type ggml_backend_dev_type(ggml_backend_dev_t device) {
}
void ggml_backend_dev_get_props(ggml_backend_dev_t device, struct ggml_backend_dev_props * props) {
GGML_ASSERT(device);
memset(props, 0, sizeof(*props));
device->iface.get_props(device, props);
}
@@ -610,6 +697,8 @@ static const struct ggml_backend_buffer_i ggml_backend_multi_buffer_i = {
/* .memset_tensor = */ NULL,
/* .set_tensor = */ NULL,
/* .get_tensor = */ NULL,
/* .set_tensor_2d = */ NULL,
/* .get_tensor_2d = */ NULL,
/* .cpy_tensor = */ NULL,
/* .clear = */ ggml_backend_multi_buffer_clear,
/* .reset = */ NULL,
@@ -1899,8 +1988,9 @@ enum ggml_status ggml_backend_tensor_alloc(ggml_backend_buffer_t buffer, struct
GGML_ASSERT(tensor->data == NULL);
GGML_ASSERT(tensor->view_src == NULL);
GGML_ASSERT(addr >= ggml_backend_buffer_get_base(buffer));
GGML_ASSERT((char *)addr + ggml_backend_buffer_get_alloc_size(buffer, tensor) <=
(char *)ggml_backend_buffer_get_base(buffer) + ggml_backend_buffer_get_size(buffer));
GGML_ASSERT(ggml_backend_buffer_is_meta(buffer) ||
(char *) addr + ggml_backend_buffer_get_alloc_size(buffer, tensor) <=
(char *) ggml_backend_buffer_get_base(buffer) + ggml_backend_buffer_get_size(buffer));
tensor->buffer = buffer;
tensor->data = addr;
@@ -2174,6 +2264,8 @@ static const struct ggml_backend_buffer_i ggml_backend_cpu_buffer_i = {
/* .memset_tensor = */ ggml_backend_cpu_buffer_memset_tensor,
/* .set_tensor = */ ggml_backend_cpu_buffer_set_tensor,
/* .get_tensor = */ ggml_backend_cpu_buffer_get_tensor,
/* .set_tensor_2d = */ NULL,
/* .get_tensor_2d = */ NULL,
/* .cpy_tensor = */ ggml_backend_cpu_buffer_cpy_tensor,
/* .clear = */ ggml_backend_cpu_buffer_clear,
/* .reset = */ NULL,
@@ -2186,6 +2278,8 @@ static const struct ggml_backend_buffer_i ggml_backend_cpu_buffer_from_ptr_i = {
/* .memset_tensor = */ ggml_backend_cpu_buffer_memset_tensor,
/* .set_tensor = */ ggml_backend_cpu_buffer_set_tensor,
/* .get_tensor = */ ggml_backend_cpu_buffer_get_tensor,
/* .set_tensor_2d = */ NULL,
/* .get_tensor_2d = */ NULL,
/* .cpy_tensor = */ ggml_backend_cpu_buffer_cpy_tensor,
/* .clear = */ ggml_backend_cpu_buffer_clear,
/* .reset = */ NULL,