ollama/llama/patches/0024-ggml-Enable-resetting-...

131 lines
6.2 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jesse Gross <jesse@ollama.com>
Date: Wed, 27 Aug 2025 14:39:48 -0700
Subject: [PATCH] ggml: Enable resetting backend devices
Touching a CUDA device causes the allocation of a primary context
with CUDA data structures (~300 MB of VRAM). If a device is
unused then it can be reset to free these data structures.
---
ggml/include/ggml-backend.h | 1 +
ggml/src/ggml-backend-impl.h | 4 ++++
ggml/src/ggml-backend.cpp | 8 ++++++++
ggml/src/ggml-cuda/ggml-cuda.cu | 17 +++++++++++++++--
ggml/src/ggml-cuda/vendors/hip.h | 1 +
5 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/ggml/include/ggml-backend.h b/ggml/include/ggml-backend.h
index b602a7c78..fda5ceb24 100644
--- a/ggml/include/ggml-backend.h
+++ b/ggml/include/ggml-backend.h
@@ -167,6 +167,7 @@ extern "C" {
GGML_API void ggml_backend_dev_get_props(ggml_backend_dev_t device, struct ggml_backend_dev_props * props);
GGML_API ggml_backend_reg_t ggml_backend_dev_backend_reg(ggml_backend_dev_t device);
GGML_API ggml_backend_t ggml_backend_dev_init(ggml_backend_dev_t device, const char * params);
+ GGML_API void ggml_backend_dev_reset(ggml_backend_dev_t device);
GGML_API ggml_backend_buffer_type_t ggml_backend_dev_buffer_type(ggml_backend_dev_t device);
GGML_API ggml_backend_buffer_type_t ggml_backend_dev_host_buffer_type(ggml_backend_dev_t device);
GGML_API ggml_backend_buffer_t ggml_backend_dev_buffer_from_host_ptr(ggml_backend_dev_t device, void * ptr, size_t size, size_t max_tensor_size);
diff --git a/ggml/src/ggml-backend-impl.h b/ggml/src/ggml-backend-impl.h
index 81749a5a3..6f10c353b 100644
--- a/ggml/src/ggml-backend-impl.h
+++ b/ggml/src/ggml-backend-impl.h
@@ -178,6 +178,10 @@ extern "C" {
ggml_backend_event_t (*event_new) (ggml_backend_dev_t dev);
void (*event_free) (ggml_backend_dev_t dev, ggml_backend_event_t event);
void (*event_synchronize) (ggml_backend_dev_t dev, ggml_backend_event_t event);
+
+ // (optional) reset device, clearing existing allocations and context
+ // the caller must ensure that there are no outstanding buffers, as these will become invalid
+ void (*reset)(ggml_backend_dev_t dev);
};
struct ggml_backend_device {
diff --git a/ggml/src/ggml-backend.cpp b/ggml/src/ggml-backend.cpp
index 05a842ed5..6556943b0 100644
--- a/ggml/src/ggml-backend.cpp
+++ b/ggml/src/ggml-backend.cpp
@@ -477,6 +477,14 @@ ggml_backend_t ggml_backend_dev_init(ggml_backend_dev_t device, const char * par
return device->iface.init_backend(device, params);
}
+void ggml_backend_dev_reset(ggml_backend_dev_t device) {
+ if (device->iface.reset == NULL) {
+ return;
+ }
+
+ device->iface.reset(device);
+}
+
ggml_backend_buffer_type_t ggml_backend_dev_buffer_type(ggml_backend_dev_t device) {
return device->iface.get_buffer_type(device);
}
diff --git a/ggml/src/ggml-cuda/ggml-cuda.cu b/ggml/src/ggml-cuda/ggml-cuda.cu
index c7f9dc3a5..e43fde523 100644
--- a/ggml/src/ggml-cuda/ggml-cuda.cu
+++ b/ggml/src/ggml-cuda/ggml-cuda.cu
@@ -103,6 +103,11 @@ int ggml_cuda_get_device() {
return id;
}
+void ggml_cuda_reset_device(int device) {
+ ggml_cuda_set_device(device);
+ CUDA_CHECK(cudaDeviceReset());
+}
+
static cudaError_t ggml_cuda_device_malloc(void ** ptr, size_t size, int device) {
ggml_cuda_set_device(device);
cudaError_t err;
@@ -3243,7 +3248,10 @@ static void ggml_backend_cuda_device_get_props(ggml_backend_dev_t dev, ggml_back
props->description = ggml_backend_cuda_device_get_description(dev);
props->id = ggml_backend_cuda_device_get_id(dev);
props->type = ggml_backend_cuda_device_get_type(dev);
- ggml_backend_cuda_device_get_memory(dev, &props->memory_free, &props->memory_total);
+
+ // Memory reporting is disabled to avoid allocation of a CUDA primary context (~300 MB per device).
+ // If you need the memory data, call ggml_backend_dev_memory() explicitly.
+ props->memory_total = props->memory_free = 0;
bool host_buffer = getenv("GGML_CUDA_NO_PINNED") == nullptr;
#ifdef GGML_CUDA_NO_PEER_COPY
@@ -3700,6 +3708,11 @@ static void ggml_backend_cuda_device_event_synchronize(ggml_backend_dev_t dev, g
CUDA_CHECK(cudaEventSynchronize((cudaEvent_t)event->context));
}
+static void ggml_backend_cuda_device_reset(ggml_backend_dev_t dev) {
+ ggml_backend_cuda_device_context * ctx = (ggml_backend_cuda_device_context *)dev->context;
+ ggml_cuda_reset_device(ctx->device);
+}
+
static const ggml_backend_device_i ggml_backend_cuda_device_interface = {
/* .get_name = */ ggml_backend_cuda_device_get_name,
/* .get_description = */ ggml_backend_cuda_device_get_description,
@@ -3716,6 +3729,7 @@ static const ggml_backend_device_i ggml_backend_cuda_device_interface = {
/* .event_new = */ ggml_backend_cuda_device_event_new,
/* .event_free = */ ggml_backend_cuda_device_event_free,
/* .event_synchronize = */ ggml_backend_cuda_device_event_synchronize,
+ /* .reset = */ ggml_backend_cuda_device_reset,
};
// backend reg
@@ -3835,7 +3849,6 @@ ggml_backend_reg_t ggml_backend_cuda_reg() {
dev_ctx->device = i;
dev_ctx->name = GGML_CUDA_NAME + std::to_string(i);
- ggml_cuda_set_device(i);
cudaDeviceProp prop;
CUDA_CHECK(cudaGetDeviceProperties(&prop, i));
dev_ctx->description = prop.name;
diff --git a/ggml/src/ggml-cuda/vendors/hip.h b/ggml/src/ggml-cuda/vendors/hip.h
index c31f31923..cf22e60d2 100644
--- a/ggml/src/ggml-cuda/vendors/hip.h
+++ b/ggml/src/ggml-cuda/vendors/hip.h
@@ -40,6 +40,7 @@
#define cudaDeviceDisablePeerAccess hipDeviceDisablePeerAccess
#define cudaDeviceEnablePeerAccess hipDeviceEnablePeerAccess
#define cudaDeviceProp hipDeviceProp_t
+#define cudaDeviceReset hipDeviceReset
#define cudaDeviceSynchronize hipDeviceSynchronize
#define cudaError_t hipError_t
#define cudaErrorPeerAccessAlreadyEnabled hipErrorPeerAccessAlreadyEnabled