Class DriverAPINativeMethods.Limits

Groups all context limit API calls

Inheritance

System.Object

DriverAPINativeMethods.Limits

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: ManagedCuda

Assembly: ManagedCuda.dll

Syntax

public static class Limits

Methods

cuCtxGetLimit(ref SizeT, CULimit)

Returns in pvalue the current size of limit. See CULimit

Declaration

public static CUResult cuCtxGetLimit(ref SizeT pvalue, CULimit limit)

Parameters

Type	Name	Description
SizeT	pvalue	Returned size in bytes of limit
CULimit	limit	Limit to query

Returns

Type	Description
CUResult	CUDA Error Codes: Success, ErrorInvalidValue, ErrorUnsupportedLimit, . Note that this function may also return error codes from previous, asynchronous launches.

cuCtxSetLimit(CULimit, SizeT)

Setting limit to value is a request by the application to update the current limit maintained by the context. The driver is free to modify the requested value to meet h/w requirements (this could be clamping to minimum or maximum values, rounding up to nearest element size, etc). The application can use cuCtxGetLimit(ref SizeT, CULimit) to find out exactly what the limit has been set to.

Setting each CULimit has its own specific restrictions, so each is discussed here:

Value	Restriction
StackSize	StackSize controls the stack size of each GPU thread. This limit is only applicable to devices of compute capability 2.0 and higher. Attempting to set this limit on devices of compute capability less than 2.0 will result in the error ErrorUnsupportedLimit being returned.
PrintfFIFOSize	PrintfFIFOSize controls the size of the FIFO used by the printf() device system call. Setting PrintfFIFOSize must be performed before loading any module that uses the printf() device system call, otherwise ErrorInvalidValue will be returned. This limit is only applicable to devices of compute capability 2.0 and higher. Attempting to set this limit on devices of compute capability less than 2.0 will result in the error ErrorUnsupportedLimit being returned.
MallocHeapSize	MallocHeapSize controls the size in bytes of the heap used by the ::malloc() and ::free() device system calls. Setting MallocHeapSize must be performed before launching any kernel that uses the ::malloc() or ::free() device system calls, otherwise ErrorInvalidValue will be returned. This limit is only applicable to devices of compute capability 2.0 and higher. Attempting to set this limit on devices of compute capability less than 2.0 will result in the error ErrorUnsupportedLimit being returned.
DevRuntimeSyncDepth	DevRuntimeSyncDepth controls the maximum nesting depth of a grid at which a thread can safely call ::cudaDeviceSynchronize(). Setting this limit must be performed before any launch of a kernel that uses the device runtime and calls ::cudaDeviceSynchronize() above the default sync depth, two levels of grids. Calls to ::cudaDeviceSynchronize() will fail with error code ::cudaErrorSyncDepthExceeded if the limitation is violated. This limit can be set smaller than the default or up the maximum launch depth of 24. When setting this limit, keep in mind that additional levels of sync depth require the driver to reserve large amounts of device memory which can no longer be used for user allocations. If these reservations of device memory fail, ::cuCtxSetLimit will return ErrorOutOfMemory, and the limit can be reset to a lower value. This limit is only applicable to devices of compute capability 3.5 and higher. Attempting to set this limit on devices of compute capability less than 3.5 will result in the error ErrorUnsupportedLimit being returned.
DevRuntimePendingLaunchCount	DevRuntimePendingLaunchCount controls the maximum number of outstanding device runtime launches that can be made from the current context. A grid is outstanding from the point of launch up until the grid is known to have been completed. Device runtime launches which violate this limitation fail and return ::cudaErrorLaunchPendingCountExceeded when ::cudaGetLastError() is called after launch. If more pending launches than the default (2048 launches) are needed for a module using the device runtime, this limit can be increased. Keep in mind that being able to sustain additional pending launches will require the driver to reserve larger amounts of device memory upfront which can no longer be used for allocations. If these reservations fail, ::cuCtxSetLimit will return ErrorOutOfMemory, and the limit can be reset to a lower value. This limit is only applicable to devices of compute capability 3.5 and higher. Attempting to set this limit on devices of compute capability less than 3.5 will result in the error ErrorUnsupportedLimit being returned.

Declaration

public static CUResult cuCtxSetLimit(CULimit limit, SizeT value)

Parameters

Type	Name	Description
CULimit	limit	Limit to set
SizeT	value	Size in bytes of limit

Returns

Type	Description
CUResult	CUDA Error Codes: Success, ErrorInvalidValue, ErrorUnsupportedLimit, . Note that this function may also return error codes from previous, asynchronous launches.