Add script to generate a raw cgo-level interface for go-nvml #155

klueska · 2025-07-17T18:59:00Z

This interface can be used in conjunction with the standard "wrapper"
interface, including the use its interface abstractions like Devices,
GPUInstances, ComputeInstances, etc.

It is invoked as nvml.CgoAPI.<api-call>, following the original function
signatures of the C-API, where there is only a single return value and
additional return values are passed as arguments.

An example usage is:
```
        // Start with using the CgoAPI
        ret := nvml.CgoAPI.Init()
        defer nvml.Shutdown()
        require.Equal(t, SUCCESS, ret, "Init should succeed")

        var count uint32
        ret = nvml.CgoAPI.DeviceGetCount(&count)
        require.Equal(t, SUCCESS, ret, "DeviceGetCount should succeed")

        var device Device
        ret = nvml.CgoAPI.DeviceGetHandleByIndex(0, &device)
        require.Equal(t, SUCCESS, ret, "DeviceGetHandleByIndex should succeed")

        // Now call Device interface methods directly
        name, ret := device.GetName()
        require.Equal(t, SUCCESS, ret, "Device.GetName should succeed")
        t.Logf("Device.GetName: %s", name)

        uuid, ret := device.GetUUID()
        require.Equal(t, SUCCESS, ret, "Device.GetUUID should succeed")
        t.Logf("Device.GetUUID: %s", uuid)

        brand, ret := device.GetBrand()
        require.Equal(t, SUCCESS, ret, "Device.GetBrand should succeed")
        t.Logf("Device.GetBrand: %v", brand)

        busType, ret := device.GetBusType()
        require.Equal(t, SUCCESS, ret, "Device.GetBusType should succeed")
        t.Logf("Device.GetBusType: %v", busType)
```

elezar · 2025-07-21T14:22:20Z

gen/nvml/generateapi.go

+	var builder strings.Builder
+
+	// Function comment
+	builder.WriteString(fmt.Sprintf("// %sHandle attempts to convert a %s to an %s.\n",


This may be easier to read if we use go templates instead.

Yes, definitely. Updated.

gen/nvml/generatecgoapi.go

Makefile

Signed-off-by: Kevin Klues <[email protected]>

This interface can be used in conjunction with the standard "wrapper" interface, including the use its interface abstractions like Devices, GPUInstances, ComputeInstances, etc. It is invoked as nvml.CgoAPI.<api-call>, following the original function signatures of the C-API, where there is only a single return value and additional return values are passed as arguments. An example usage is: ``` // Start with using the CgoAPI ret := nvml.CgoAPI.Init() defer nvml.Shutdown() require.Equal(t, SUCCESS, ret, "Init should succeed") var count uint32 ret = nvml.CgoAPI.DeviceGetCount(&count) require.Equal(t, SUCCESS, ret, "DeviceGetCount should succeed") var device Device ret = nvml.CgoAPI.DeviceGetHandleByIndex(0, &device) require.Equal(t, SUCCESS, ret, "DeviceGetHandleByIndex should succeed") // Now call Device interface methods directly name, ret := device.GetName() require.Equal(t, SUCCESS, ret, "Device.GetName should succeed") t.Logf("Device.GetName: %s", name) uuid, ret := device.GetUUID() require.Equal(t, SUCCESS, ret, "Device.GetUUID should succeed") t.Logf("Device.GetUUID: %s", uuid) brand, ret := device.GetBrand() require.Equal(t, SUCCESS, ret, "Device.GetBrand should succeed") t.Logf("Device.GetBrand: %v", brand) busType, ret := device.GetBusType() require.Equal(t, SUCCESS, ret, "Device.GetBusType should succeed") t.Logf("Device.GetBusType: %v", busType) ``` Signed-off-by: Kevin Klues <[email protected]>

Signed-off-by: Kevin Klues <[email protected]>

pkg/nvml/cgoapi_test.go

klueska · 2025-08-06T08:37:22Z

@elezar what are your thoughts on the name of "CgoAPI"? I'm not sold on it, but couldn't come up with anything else.

elezar

My one question is whether we want to use the cgoapi internally to provide more idiomatic go wrappers? Maybe as part of something like #125?

(This would obviously be a follow-up).

elezar · 2025-08-15T13:47:04Z

pkg/nvml/lib.go

 var deviceGetGraphicsRunningProcesses = deviceGetGraphicsRunningProcesses_v1
+var nvmlDeviceGetMPSComputeRunningProcesses = nvmlDeviceGetMPSComputeRunningProcesses_v3
 var deviceGetMPSComputeRunningProcesses = deviceGetMPSComputeRunningProcesses_v1
+var nvmlGetBlacklistDeviceCount = nvmlGetExcludedDeviceCount


I noticed this in #156 too. These are not versioned and are simple aliases. Should we move them out of this block?

elezar · 2025-08-15T13:48:59Z

pkg/nvml/lib.go

 }

-// Default all versioned APIs to v1 (to infer the types)
+// BEGIN_UNVERSIONED_FUNCTIONS


It is common for machine readable comments not have a leading spaces. What about:

Suggested change

// BEGIN_UNVERSIONED_FUNCTIONS

//generatecgoapi: BEGIN_UNVERSIONED_FUNCTIONS

(and below)

elezar · 2025-08-15T13:53:39Z

pkg/nvml/cgoapi_test.go

+	ret = CgoAPI.DeviceGetCount(&count)
+	require.Equal(t, SUCCESS, ret, "DeviceGetCount should succeed")
+
+	// Test getting a device handle by index


Is the intent to try to get an invalid device? Or do we want to rather do something like:

if count == 0 { t.Skip("No devices available for testing, skipping device-specific tests") }

so that we don't require redundant nesting?

elezar · 2025-08-15T13:56:00Z

pkg/nvml/cgoapi_test.go

+}
+
+// TestCgoAPIDeviceMethods exercises various device-related CgoAPI methods.
+func TestCgoAPIDeviceMethods(t *testing.T) {


It's not quite clear to me how this is different from the functionality tested in the previous test case -- with the exception of non-overlapping function calls.

elezar · 2025-08-15T13:57:18Z

pkg/nvml/lib.go

 var nvmlEventSetWait = nvmlEventSetWait_v1
 var nvmlDeviceGetAttributes = nvmlDeviceGetAttributes_v1
 var nvmlComputeInstanceGetInfo = nvmlComputeInstanceGetInfo_v1
+var nvmlDeviceGetComputeRunningProcesses = nvmlDeviceGetComputeRunningProcesses_v3


Why are we defaulting to the _v3 versions here?

elezar · 2025-08-21T07:28:13Z

@elezar what are your thoughts on the name of "CgoAPI"? I'm not sold on it, but couldn't come up with anything else.

Does the name "leak" implementation details in some way? Strictly speaking these are more "accurate" wrappers to the NVML functions themselves since there are fewer modifications to make them more go-like. How much effort would it be to make these the top-level functions and come up with a name for the existing functions. Especially considering proposed changes such as #120

klueska force-pushed the add-direct-cgo-api branch 2 times, most recently from b9b8bd1 to cafb054 Compare July 21, 2025 10:07

elezar reviewed Jul 21, 2025

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elezar reviewed Jul 21, 2025

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klueska force-pushed the add-direct-cgo-api branch 2 times, most recently from c20e2b1 to 9db4a5a Compare July 22, 2025 15:00

klueska added 4 commits July 22, 2025 20:14

Add additional versioned nvml* functions previously undefined

16f6911

Signed-off-by: Kevin Klues <[email protected]>

Auto generate funcs to convert interface types to their nvml* types

6946561

Signed-off-by: Kevin Klues <[email protected]>

Add script to make target and commit generated CgoAPI

5913ac9

Signed-off-by: Kevin Klues <[email protected]>

klueska force-pushed the add-direct-cgo-api branch from 9db4a5a to 5913ac9 Compare July 22, 2025 20:15

vbalain reviewed Jul 29, 2025

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pkg/nvml/cgoapi_test.go Show resolved Hide resolved

elezar reviewed Aug 6, 2025

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elezar reviewed Aug 15, 2025

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klueska marked this pull request as draft August 22, 2025 09:18

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Add script to generate a raw cgo-level interface for go-nvml #155

Add script to generate a raw cgo-level interface for go-nvml #155

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	// BEGIN_UNVERSIONED_FUNCTIONS
	//generatecgoapi: BEGIN_UNVERSIONED_FUNCTIONS

Add script to generate a raw cgo-level interface for go-nvml #155

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Add script to generate a raw cgo-level interface for go-nvml #155

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