ggml: Export GPU UUIDs

This enables matching up devices and information reported by the backend
with system management libraries such as nvml to get accurate free
memory reporting.

llama/patches/0017-ggml-Export-GPU-UUIDs.patch

+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jesse Gross <jesse@ollama.com>
+Date: Thu, 24 Apr 2025 14:48:51 -0700
+Subject: [PATCH] ggml: Export GPU UUIDs
+
+This enables matching up devices and information reported by the backend
+with tools (e.g. nvidia-smi) and system management libraries (e.g. nvml).
+---
+ ggml/include/ggml-backend.h      |  1 +
+ ggml/src/ggml-cuda/ggml-cuda.cu  | 33 ++++++++++++++++++++++++++++++++
+ ggml/src/ggml-metal/ggml-metal.m |  1 +
+ 3 files changed, 35 insertions(+)
+
+diff --git a/ggml/include/ggml-backend.h b/ggml/include/ggml-backend.h
+index 74e46716..a880df33 100644
+--- a/ggml/include/ggml-backend.h
++++ b/ggml/include/ggml-backend.h
+@@ -152,6 +152,7 @@ extern "C" {
+     struct ggml_backend_dev_props {
+         const char * name;
+         const char * description;
++        const char * uuid;
+         size_t memory_free;
+         size_t memory_total;
+         enum ggml_backend_dev_type type;
+diff --git a/ggml/src/ggml-cuda/ggml-cuda.cu b/ggml/src/ggml-cuda/ggml-cuda.cu
+index cb0d8528..4c829153 100644
+--- a/ggml/src/ggml-cuda/ggml-cuda.cu
++++ b/ggml/src/ggml-cuda/ggml-cuda.cu
+@@ -2884,6 +2884,7 @@ struct ggml_backend_cuda_device_context {
+     int device;
+     std::string name;
+     std::string description;
++    std::string uuid;
+ };
+ 
+ static const char * ggml_backend_cuda_device_get_name(ggml_backend_dev_t dev) {
+@@ -2896,6 +2897,11 @@ static const char * ggml_backend_cuda_device_get_description(ggml_backend_dev_t
+     return ctx->description.c_str();
+ }
+ 
++static const char * ggml_backend_cuda_device_get_uuid(ggml_backend_dev_t dev) {
++    ggml_backend_cuda_device_context * ctx = (ggml_backend_cuda_device_context *)dev->context;
++    return ctx->uuid.c_str();
++}
++
+ static void ggml_backend_cuda_device_get_memory(ggml_backend_dev_t dev, size_t * free, size_t * total) {
+     ggml_backend_cuda_device_context * ctx = (ggml_backend_cuda_device_context *)dev->context;
+     ggml_cuda_set_device(ctx->device);
+@@ -2910,6 +2916,7 @@ static enum ggml_backend_dev_type ggml_backend_cuda_device_get_type(ggml_backend
+ static void ggml_backend_cuda_device_get_props(ggml_backend_dev_t dev, ggml_backend_dev_props * props) {
+     props->name        = ggml_backend_cuda_device_get_name(dev);
+     props->description = ggml_backend_cuda_device_get_description(dev);
++    props->uuid        = ggml_backend_cuda_device_get_uuid(dev);
+     props->type        = ggml_backend_cuda_device_get_type(dev);
+     ggml_backend_cuda_device_get_memory(dev, &props->memory_free, &props->memory_total);
+ 
+@@ -3458,6 +3465,32 @@ ggml_backend_reg_t ggml_backend_cuda_reg() {
+                 CUDA_CHECK(cudaGetDeviceProperties(&prop, i));
+                 dev_ctx->description = prop.name;
+ 
++                #if !defined(GGML_USE_HIP)
++                char uuid[64];
++                snprintf(uuid, sizeof(uuid),
++                    "GPU-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
++                    (unsigned char)prop.uuid.bytes[0],
++                    (unsigned char)prop.uuid.bytes[1],
++                    (unsigned char)prop.uuid.bytes[2],
++                    (unsigned char)prop.uuid.bytes[3],
++                    (unsigned char)prop.uuid.bytes[4],
++                    (unsigned char)prop.uuid.bytes[5],
++                    (unsigned char)prop.uuid.bytes[6],
++                    (unsigned char)prop.uuid.bytes[7],
++                    (unsigned char)prop.uuid.bytes[8],
++                    (unsigned char)prop.uuid.bytes[9],
++                    (unsigned char)prop.uuid.bytes[10],
++                    (unsigned char)prop.uuid.bytes[11],
++                    (unsigned char)prop.uuid.bytes[12],
++                    (unsigned char)prop.uuid.bytes[13],
++                    (unsigned char)prop.uuid.bytes[14],
++                    (unsigned char)prop.uuid.bytes[15]
++                  );
++                dev_ctx->uuid = uuid;
++                #else
++                dev_ctx->uuid = "GPU-" + std::string(prop.uuid.bytes, 16);
++                #endif
++
+                 ggml_backend_dev_t dev = new ggml_backend_device {
+                     /* .iface   = */ ggml_backend_cuda_device_interface,
+                     /* .reg     = */ &reg,
+diff --git a/ggml/src/ggml-metal/ggml-metal.m b/ggml/src/ggml-metal/ggml-metal.m
+index 1b56f858..ee4f2dcb 100644
+--- a/ggml/src/ggml-metal/ggml-metal.m
++++ b/ggml/src/ggml-metal/ggml-metal.m
+@@ -5703,6 +5703,7 @@ static enum ggml_backend_dev_type ggml_backend_metal_device_get_type(ggml_backen
+ static void ggml_backend_metal_device_get_props(ggml_backend_dev_t dev, struct ggml_backend_dev_props * props) {
+     props->name        = ggml_backend_metal_device_get_name(dev);
+     props->description = ggml_backend_metal_device_get_description(dev);
++    props->uuid        = "0";
+     props->type        = ggml_backend_metal_device_get_type(dev);
+     ggml_backend_metal_device_get_memory(dev, &props->memory_free, &props->memory_total);
+     props->caps = (struct ggml_backend_dev_caps) {

ml/backend.go

@@ -124,6 +124,10 @@ type DeviceMemory struct {
 	// may not be persistent across instances of the runner.
 	Name string
 
+	// UUID is a unique persistent identifier for the device for matching
+	// with system management libraries
+	UUID string
+
 	// Weights is the per-layer memory needed for the model weights.
 	Weights []Memory
 
@@ -152,6 +156,10 @@ func (m DeviceMemory) LogValue() slog.Value {
 		attrs = append(attrs, slog.Any("Graph", m.Graph))
 	}
 
+	if len(attrs) > 0 && m.UUID != "" {
+		attrs = append([]slog.Attr{slog.String("UUID", m.UUID)}, attrs...)
+	}
+
 	return slog.GroupValue(attrs...)
 }
 

ml/backend/ggml/ggml.go

@@ -136,6 +136,9 @@ func New(modelPath string, params ml.BackendParams) (ml.Backend, error) {
 	}
 
 	requiredMemory.CPU.Name = C.GoString(C.ggml_backend_dev_name(cpuDeviceBufferType.d))
+	var props C.struct_ggml_backend_dev_props
+	C.ggml_backend_dev_get_props(cpuDeviceBufferType.d, &props)
+	requiredMemory.CPU.UUID = C.GoString(props.uuid)
 	requiredMemory.CPU.Weights = make([]ml.Memory, blocks+1)
 	requiredMemory.CPU.Cache = make([]ml.Memory, blocks+1)
 
@@ -150,6 +153,9 @@ func New(modelPath string, params ml.BackendParams) (ml.Backend, error) {
 		})
 		btDeviceMemory[bt] = &requiredMemory.GPUs[i]
 		requiredMemory.GPUs[i].Name = C.GoString(C.ggml_backend_dev_name(d))
+		var props C.struct_ggml_backend_dev_props
+		C.ggml_backend_dev_get_props(d, &props)
+		requiredMemory.GPUs[i].UUID = C.GoString(props.uuid)
 		requiredMemory.GPUs[i].Weights = make([]ml.Memory, blocks+1)
 		requiredMemory.GPUs[i].Cache = make([]ml.Memory, blocks+1)
 	}

ml/backend/ggml/ggml/include/ggml-backend.h

@@ -152,6 +152,7 @@ extern "C" {
     struct ggml_backend_dev_props {
         const char * name;
         const char * description;
+        const char * uuid;
         size_t memory_free;
         size_t memory_total;
         enum ggml_backend_dev_type type;

ml/backend/ggml/ggml/src/ggml-cuda/ggml-cuda.cu

@@ -2884,6 +2884,7 @@ struct ggml_backend_cuda_device_context {
     int device;
     std::string name;
     std::string description;
+    std::string uuid;
 };
 
 static const char * ggml_backend_cuda_device_get_name(ggml_backend_dev_t dev) {
@@ -2896,6 +2897,11 @@ static const char * ggml_backend_cuda_device_get_description(ggml_backend_dev_t
     return ctx->description.c_str();
 }
 
+static const char * ggml_backend_cuda_device_get_uuid(ggml_backend_dev_t dev) {
+    ggml_backend_cuda_device_context * ctx = (ggml_backend_cuda_device_context *)dev->context;
+    return ctx->uuid.c_str();
+}
+
 static void ggml_backend_cuda_device_get_memory(ggml_backend_dev_t dev, size_t * free, size_t * total) {
     ggml_backend_cuda_device_context * ctx = (ggml_backend_cuda_device_context *)dev->context;
     ggml_cuda_set_device(ctx->device);
@@ -2910,6 +2916,7 @@ static enum ggml_backend_dev_type ggml_backend_cuda_device_get_type(ggml_backend
 static void ggml_backend_cuda_device_get_props(ggml_backend_dev_t dev, ggml_backend_dev_props * props) {
     props->name        = ggml_backend_cuda_device_get_name(dev);
     props->description = ggml_backend_cuda_device_get_description(dev);
+    props->uuid        = ggml_backend_cuda_device_get_uuid(dev);
     props->type        = ggml_backend_cuda_device_get_type(dev);
     ggml_backend_cuda_device_get_memory(dev, &props->memory_free, &props->memory_total);
 
@@ -3458,6 +3465,32 @@ ggml_backend_reg_t ggml_backend_cuda_reg() {
                 CUDA_CHECK(cudaGetDeviceProperties(&prop, i));
                 dev_ctx->description = prop.name;
 
+                #if !defined(GGML_USE_HIP)
+                char uuid[64];
+                snprintf(uuid, sizeof(uuid),
+                    "GPU-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+                    (unsigned char)prop.uuid.bytes[0],
+                    (unsigned char)prop.uuid.bytes[1],
+                    (unsigned char)prop.uuid.bytes[2],
+                    (unsigned char)prop.uuid.bytes[3],
+                    (unsigned char)prop.uuid.bytes[4],
+                    (unsigned char)prop.uuid.bytes[5],
+                    (unsigned char)prop.uuid.bytes[6],
+                    (unsigned char)prop.uuid.bytes[7],
+                    (unsigned char)prop.uuid.bytes[8],
+                    (unsigned char)prop.uuid.bytes[9],
+                    (unsigned char)prop.uuid.bytes[10],
+                    (unsigned char)prop.uuid.bytes[11],
+                    (unsigned char)prop.uuid.bytes[12],
+                    (unsigned char)prop.uuid.bytes[13],
+                    (unsigned char)prop.uuid.bytes[14],
+                    (unsigned char)prop.uuid.bytes[15]
+                  );
+                dev_ctx->uuid = uuid;
+                #else
+                dev_ctx->uuid = "GPU-" + std::string(prop.uuid.bytes, 16);
+                #endif
+
                 ggml_backend_dev_t dev = new ggml_backend_device {
                     /* .iface   = */ ggml_backend_cuda_device_interface,
                     /* .reg     = */ &reg,

ml/backend/ggml/ggml/src/ggml-metal/ggml-metal.m

@@ -5703,6 +5703,7 @@ static enum ggml_backend_dev_type ggml_backend_metal_device_get_type(ggml_backen
 static void ggml_backend_metal_device_get_props(ggml_backend_dev_t dev, struct ggml_backend_dev_props * props) {
     props->name        = ggml_backend_metal_device_get_name(dev);
     props->description = ggml_backend_metal_device_get_description(dev);
+    props->uuid        = "0";
     props->type        = ggml_backend_metal_device_get_type(dev);
     ggml_backend_metal_device_get_memory(dev, &props->memory_free, &props->memory_total);
     props->caps = (struct ggml_backend_dev_caps) {