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//! # CUDA context management //! //! Most CUDA functions require a context. A CUDA context is analogous to a CPU process - it's //! an isolated container for all runtime state, including configuration settings and the //! device/unified/page-locked memory allocations. Each context has a separate memory space, and //! pointers from one context do not work in another. Each context is associated with a single //! device. Although it is possible to have multiple contexts associated with a single device, this //! is strongly discouraged as it can cause a significant loss of performance. //! //! CUDA keeps a thread-local stack of contexts which the programmer can push to or pop from. //! The top context in that stack is known as the "current" context and it is used in most CUDA //! API calls. One context can be safely made current in multiple CPU threads. //! //! # Safety //! //! The CUDA context management API does not fit easily into Rust's safety guarantees. //! //! The thread-local stack (as well as the fact that any context can be on the stack for any number //! of threads) means there is no clear owner for a CUDA context, but it still has to be cleaned up. //! Also, the fact that a context can be current to multiple threads at once means that there can be //! multiple implicit references to a context which are not controlled by Rust. //! //! RustaCUDA handles ownership by providing an owning [`Context`](struct.Context.html) struct and //! a non-owning [`UnownedContext`](struct.UnownedContext.html). When the `Context` is dropped, the //! backing context is destroyed. The context could be current on other threads, though. In this //! case, the context is still destroyed, and attempts to access the context on other threads will //! fail with an error. This is (mostly) safe, if a bit inconvenient. It's only mostly safe because //! other threads could be accessing that context while the destructor is running on this thread, //! which could result in undefined behavior. //! //! In short, Rust's thread-safety guarantees cannot fully protect use of the context management //! functions. The programmer must ensure that no other OS threads are using the `Context` when it //! is dropped. //! //! # Examples //! //! For most commmon uses (one device, one OS thread) it should suffice to create a single context: //! //! ``` //! use rustacuda::device::Device; //! use rustacuda::context::{Context, ContextFlags}; //! # use std::error::Error; //! # fn main () -> Result<(), Box<dyn Error>> { //! //! rustacuda::init(rustacuda::CudaFlags::empty())?; //! let device = Device::get_device(0)?; //! let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; //! // call RustaCUDA functions which use the context //! //! // The context will be destroyed when dropped or it falls out of scope. //! drop(context); //! # Ok(()) //! # } //! ``` //! //! If you have multiple OS threads that each submit work to the same device, you can get a handle //! to the single context and pass it to each thread. //! //! ``` //! # use rustacuda::context::{Context, ContextFlags, CurrentContext}; //! # use rustacuda::device::Device; //! # use std::error::Error; //! # fn main() -> Result<(), Box<dyn Error>> { //! # rustacuda::init(rustacuda::CudaFlags::empty())?; //! # let device = Device::get_device(0)?; //! // As before //! let context = //! Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; //! let mut join_handles = vec![]; //! //! for _ in 0..4 { //! let unowned = context.get_unowned(); //! let join_handle = std::thread::spawn(move || { //! CurrentContext::set_current(&unowned).unwrap(); //! // Call RustaCUDA functions which use the context //! }); //! join_handles.push(join_handle); //! } //! // We must ensure that the other threads are not using the context when it's destroyed. //! for handle in join_handles { //! handle.join().unwrap(); //! } //! // Now it's safe to drop the context. //! drop(context); //! # Ok(()) //! # } //! ``` //! //! If you have multiple devices, each device needs its own context. //! //! ``` //! # use rustacuda::device::Device; //! # use rustacuda::context::{Context, ContextStack, ContextFlags, CurrentContext}; //! # use std::error::Error; //! # //! # fn main() -> Result<(), Box<dyn Error>> { //! # rustacuda::init(rustacuda::CudaFlags::empty())?; //! // Create and pop contexts for each device //! let mut contexts = vec![]; //! for device in Device::devices()? { //! let device = device?; //! let ctx = //! Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; //! ContextStack::pop()?; //! contexts.push(ctx); //! } //! CurrentContext::set_current(&contexts[0])?; //! //! // Call RustaCUDA functions which will use the context //! //! # Ok(()) //! # } //! ``` use crate::device::Device; use crate::error::{CudaResult, DropResult, ToResult}; use crate::private::Sealed; use crate::CudaApiVersion; use cuda_sys::cuda::{self, CUcontext}; use std::mem; use std::mem::transmute; use std::ptr; /// This enumeration represents configuration settings for devices which share hardware resources /// between L1 cache and shared memory. /// /// Note that this is only a preference - the driver will use the requested configuration if /// possible, but it is free to choose a different configuration if required to execute functions. /// /// See /// [CurrentContext::get_cache_config](struct.CurrentContext.html#method.get_cache_config) and /// [CurrentContext::set_cache_config](struct.CurrentContext.html#method.set_cache_config) to get /// and set the cache config for the current context. #[repr(u32)] #[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)] pub enum CacheConfig { /// No preference for shared memory or L1 (default) PreferNone = 0, /// Prefer larger shared memory and smaller L1 cache PreferShared = 1, /// Prefer larger L1 cache and smaller shared memory PreferL1 = 2, /// Prefer equal-sized L1 cache and shared memory PreferEqual = 3, #[doc(hidden)] __Nonexhaustive, } /// This enumeration represents the limited resources which can be accessed through /// [CurrentContext::get_resource_limit](struct.CurrentContext.html#method.get_resource_limit) and /// [CurrentContext::set_resource_limit](struct.CurrentContext.html#method.set_resource_limit). #[repr(u32)] #[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)] pub enum ResourceLimit { /// The size in bytes of each GPU thread stack StackSize = 0, /// The size in bytes of the FIFO used by the `printf()` device system call. PrintfFifoSize = 1, /// The size in bytes of the heap used by the `malloc()` and `free()` device system calls. /// /// Note that this is used for memory allocated within a kernel launch; it is not related to the /// device memory allocated by the host. MallocHeapSize = 2, /// The maximum nesting depth of a grid at which a thread can safely call /// `cudaDeviceSynchronize()` to wait on child grid launches to complete. DeviceRuntimeSynchronizeDepth = 3, /// The maximum number of outstanding device runtime launches that can be made from the current /// context. DeviceRuntimePendingLaunchCount = 4, /// L2 cache fetch granularity MaxL2FetchGranularity = 5, #[doc(hidden)] __Nonexhaustive, } /// This enumeration represents the options for configuring the shared memory bank size. /// /// See /// [CurrentContext::get_shared_memory_config](struct.CurrentContext.html#method.get_shared_memory_config) and /// [CurrentContext::set_shared_memory_config](struct.CurrentContext.html#method.set_shared_memory_config) to get /// and set the cache config for the current context. #[repr(u32)] #[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)] pub enum SharedMemoryConfig { /// Set shared-memory bank size to the default. DefaultBankSize = 0, /// Set shared-memory bank width to four bytes FourByteBankSize = 1, /// Set shared-memory bank width to eight bytes EightByteBankSize = 2, #[doc(hidden)] __Nonexhaustive, } bitflags! { /// Bit flags for initializing the CUDA context. /// /// If you're not sure which flags to use, `MAP_HOST | SCHED_AUTO` is a good default. pub struct ContextFlags: u32 { /// Instructs CUDA to actively spin when waiting for results from the GPU. This can decrease /// latency when waiting for the GPU, but may lower the performance of other CPU threads /// if they are performing work in parallel with the CUDA thread. const SCHED_SPIN = 0x01; /// Instructs CUDA to yield its thread when waiting for results from the GPU. This can /// increase latency when waiting for the GPU, but can increase the performance of CPU /// threads performing work in parallel with the GPU. const SCHED_YIELD = 0x02; /// Instructs CUDA to block the CPU thread on a synchronization primitive when waiting for /// the GPU to finish work. const SCHED_BLOCKING_SYNC = 0x04; /// Instructs CUDA to automatically choose whether to yield to other OS threads while waiting /// for the GPU, or to spin the OS thread. This is the default. const SCHED_AUTO = 0x00; /// Instructs CUDA to support mapped pinned allocations. This flag must be set in order to /// use page-locked memory (see [LockedBuffer](../memory/struct.LockedBuffer.html])). const MAP_HOST = 0x08; /// Instruct CUDA not to reduce local memory after resizing local memory for a kernel. This /// can prevent thrashing by local memory allocations when launching many kernels with high /// local memory usage at the cost of potentially increased memory usage. const LMEM_RESIZE_TO_MAX = 0x10; } } /// Owned handle to a CUDA context. /// /// The context will be destroyed when this goes out of scope. If this is the current context on /// the current OS thread, the next context on the stack (if any) will be made current. Note that /// the context will be destroyed even if other threads are still using it. Attempts to access the /// destroyed context from another thread will return an error. #[derive(Debug)] pub struct Context { inner: CUcontext, } impl Context { /// Create a CUDA context for the given device. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{Context, ContextFlags}; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// rustacuda::init(rustacuda::CudaFlags::empty())?; /// let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// # Ok(()) /// # } /// ``` pub fn create_and_push(flags: ContextFlags, device: Device) -> CudaResult<Context> { unsafe { // CUDA only provides a create-and-push operation, but that makes it hard to provide // lifetime guarantees so we create-and-push, then pop, then the programmer has to // push again. let mut ctx: CUcontext = ptr::null_mut(); cuda::cuCtxCreate_v2( &mut ctx as *mut CUcontext, flags.bits(), device.into_inner(), ) .to_result()?; Ok(Context { inner: ctx }) } } /// Get the API version used to create this context. /// /// This is not necessarily the latest version supported by the driver. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{Context, ContextFlags}; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// rustacuda::init(rustacuda::CudaFlags::empty())?; /// let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let version = context.get_api_version()?; /// # Ok(()) /// # } /// ``` pub fn get_api_version(&self) -> CudaResult<CudaApiVersion> { unsafe { let mut api_version = 0u32; cuda::cuCtxGetApiVersion(self.inner, &mut api_version as *mut u32).to_result()?; Ok(CudaApiVersion { version: api_version as i32, }) } } /// Returns an non-owning handle to this context. /// /// This is useful for sharing a single context between threads (though see the module-level /// documentation for safety details!). /// /// # Example ////* */ /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{Context, ContextFlags}; /// # use std::error::Error; /// # /// # fn main() -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let unowned = context.get_unowned(); /// # Ok(()) /// # } /// ``` pub fn get_unowned(&self) -> UnownedContext { UnownedContext { inner: self.inner } } /// Destroy a `Context`, returning an error. /// /// Destroying a context can return errors from previous asynchronous work. This function /// destroys the given context and returns the error and the un-destroyed context on failure. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{Context, ContextFlags}; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// match Context::drop(context) { /// Ok(()) => println!("Successfully destroyed"), /// Err((e, ctx)) => { /// println!("Failed to destroy context: {:?}", e); /// // Do something with ctx /// }, /// } /// # Ok(()) /// # } /// ``` pub fn drop(mut ctx: Context) -> DropResult<Context> { if ctx.inner.is_null() { return Ok(()); } unsafe { let inner = mem::replace(&mut ctx.inner, ptr::null_mut()); match cuda::cuCtxDestroy_v2(inner).to_result() { Ok(()) => { mem::forget(ctx); Ok(()) } Err(e) => Err((e, Context { inner })), } } } } impl Drop for Context { fn drop(&mut self) { if self.inner.is_null() { return; } unsafe { let inner = mem::replace(&mut self.inner, ptr::null_mut()); // No choice but to panic here. cuda::cuCtxDestroy_v2(inner) .to_result() .expect("Failed to destroy context"); } } } /// Sealed trait for `Context` and `UnownedContext`. Not intended for use outside of RustaCUDA. pub trait ContextHandle: Sealed { #[doc(hidden)] fn get_inner(&self) -> CUcontext; } impl Sealed for Context {} impl ContextHandle for Context { fn get_inner(&self) -> CUcontext { self.inner } } impl Sealed for UnownedContext {} impl ContextHandle for UnownedContext { fn get_inner(&self) -> CUcontext { self.inner } } /// Non-owning handle to a CUDA context. #[derive(Debug, Clone)] pub struct UnownedContext { inner: CUcontext, } unsafe impl Send for UnownedContext {} unsafe impl Sync for UnownedContext {} impl UnownedContext { /// Get the API version used to create this context. /// /// This is not necessarily the latest version supported by the driver. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{Context, ContextFlags}; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let unowned = context.get_unowned(); /// let version = unowned.get_api_version()?; /// # /// # Ok(()) /// # } /// ``` pub fn get_api_version(&self) -> CudaResult<CudaApiVersion> { unsafe { let mut api_version = 0u32; cuda::cuCtxGetApiVersion(self.inner, &mut api_version as *mut u32).to_result()?; Ok(CudaApiVersion { version: api_version as i32, }) } } } /// Type used to represent the thread-local context stack. #[derive(Debug)] pub struct ContextStack; impl ContextStack { /// Pop the current context off the stack and return the handle. That context may then be made /// current again (perhaps on a different CPU thread) by calling [push](#method.push). /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{Context, ContextFlags, ContextStack}; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// # let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let unowned = ContextStack::pop()?; /// # /// # Ok(()) /// # } /// ``` pub fn pop() -> CudaResult<UnownedContext> { unsafe { let mut ctx: CUcontext = ptr::null_mut(); cuda::cuCtxPopCurrent_v2(&mut ctx as *mut CUcontext).to_result()?; Ok(UnownedContext { inner: ctx }) } } /// Push the given context to the top of the stack /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{Context, ContextFlags, ContextStack}; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// # let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let unowned = ContextStack::pop()?; /// ContextStack::push(&unowned)?; /// # Ok(()) /// # } /// ``` pub fn push<C: ContextHandle>(ctx: &C) -> CudaResult<()> { unsafe { cuda::cuCtxPushCurrent_v2(ctx.get_inner()).to_result()?; Ok(()) } } } /// Struct representing a range of stream priorities. /// /// By convention, lower numbers imply greater priorities. The range of meaningful stream priorities /// is given by `[greatest, least]` - that is (numerically), `greatest <= least`. #[derive(Debug, Clone, Hash, Eq, PartialEq)] pub struct StreamPriorityRange { /// The least stream priority pub least: i32, /// The greatest stream priority pub greatest: i32, } /// Type representing the top context in the thread-local stack. #[derive(Debug)] pub struct CurrentContext; impl CurrentContext { /// Returns the preferred cache configuration for the current context. /// /// On devices where the L1 cache and shared memory use the same hardware resources, this /// function returns the preferred cache configuration for the current context. For devices /// where the size of the L1 cache and shared memory are fixed, this will always return /// `CacheConfig::PreferNone`. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let cache_config = CurrentContext::get_cache_config()?; /// # Ok(()) /// # } /// ``` pub fn get_cache_config() -> CudaResult<CacheConfig> { unsafe { let mut config = CacheConfig::PreferNone; cuda::cuCtxGetCacheConfig(&mut config as *mut CacheConfig as *mut cuda::CUfunc_cache) .to_result()?; Ok(config) } } /// Return the device ID for the current context. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let device = CurrentContext::get_device()?; /// # Ok(()) /// # } /// ``` pub fn get_device() -> CudaResult<Device> { unsafe { let mut device = Device { device: 0 }; cuda::cuCtxGetDevice(&mut device.device as *mut cuda::CUdevice).to_result()?; Ok(device) } } /// Return the context flags for the current context. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let flags = CurrentContext::get_flags()?; /// # Ok(()) /// # } /// ``` pub fn get_flags() -> CudaResult<ContextFlags> { unsafe { let mut flags = 0u32; cuda::cuCtxGetFlags(&mut flags as *mut u32).to_result()?; Ok(ContextFlags::from_bits_truncate(flags)) } } /// Return resource limits for the current context. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext, ResourceLimit }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let stack_size = CurrentContext::get_resource_limit(ResourceLimit::StackSize)?; /// # Ok(()) /// # } /// ``` pub fn get_resource_limit(resource: ResourceLimit) -> CudaResult<usize> { unsafe { let mut limit: usize = 0; cuda::cuCtxGetLimit(&mut limit as *mut usize, transmute(resource)).to_result()?; Ok(limit) } } /// Return resource limits for the current context. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext, ResourceLimit }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let shared_mem_config = CurrentContext::get_shared_memory_config()?; /// # Ok(()) /// # } /// ``` pub fn get_shared_memory_config() -> CudaResult<SharedMemoryConfig> { unsafe { let mut cfg = SharedMemoryConfig::DefaultBankSize; cuda::cuCtxGetSharedMemConfig( &mut cfg as *mut SharedMemoryConfig as *mut cuda::CUsharedconfig, ) .to_result()?; Ok(cfg) } } /// Return the least and greatest stream priorities. /// /// If the program attempts to create a stream with a priority outside of this range, it will be /// automatically clamped to within the valid range. If the device does not support stream /// priorities, the returned range will contain zeroes. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext}; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let priority_range = CurrentContext::get_stream_priority_range()?; /// # Ok(()) /// # } /// ``` pub fn get_stream_priority_range() -> CudaResult<StreamPriorityRange> { unsafe { let mut range = StreamPriorityRange { least: 0, greatest: 0, }; cuda::cuCtxGetStreamPriorityRange( &mut range.least as *mut i32, &mut range.greatest as *mut i32, ) .to_result()?; Ok(range) } } /// Sets the preferred cache configuration for the current context. /// /// On devices where L1 cache and shared memory use the same hardware resources, this sets the /// preferred cache configuration for the current context. This is only a preference. The /// driver will use the requested configuration if possible, but is free to choose a different /// configuration if required to execute the function. /// /// This setting does nothing on devices where the size of the L1 cache and shared memory are /// fixed. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext, CacheConfig }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// CurrentContext::set_cache_config(CacheConfig::PreferL1)?; /// # Ok(()) /// # } /// ``` pub fn set_cache_config(cfg: CacheConfig) -> CudaResult<()> { unsafe { cuda::cuCtxSetCacheConfig(transmute(cfg)).to_result() } } /// Sets a requested resource limit for the current context. /// /// Note that this is only a request; the driver is free to modify the requested value to meet /// hardware requirements. Each limit has some specific restrictions. /// /// * `StackSize`: Controls the stack size in bytes for each GPU thread /// * `PrintfFifoSize`: Controls the size in bytes of the FIFO used by the `printf()` device /// system call. This cannot be changed after a kernel has been launched which uses the /// `printf()` function. /// * `MallocHeapSize`: Controls the size in bytes of the heap used by the `malloc()` and `free()` /// device system calls. This cannot be changed aftr a kernel has been launched which uses the /// `malloc()` and `free()` system calls. /// * `DeviceRuntimeSyncDepth`: Controls the maximum nesting depth of a grid at which a thread /// can safely call `cudaDeviceSynchronize()`. This cannot be changed after a kernel has been /// launched which uses the device runtime. 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 device allocations. /// * `DeviceRuntimePendingLaunchCount`: 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 the launch up until the grid is known to have completed. Keep in mind that /// increasing this limit will require the driver to reserve larger amounts of device memory /// which can no longer be used for device allocations. /// * `MaxL2FetchGranularity`: Controls the L2 fetch granularity. This is purely a performance /// hint and it can be ignored or clamped depending on the platform. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext, ResourceLimit }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// CurrentContext::set_resource_limit(ResourceLimit::StackSize, 2048)?; /// # Ok(()) /// # } /// ``` pub fn set_resource_limit(resource: ResourceLimit, limit: usize) -> CudaResult<()> { unsafe { cuda::cuCtxSetLimit(transmute(resource), limit).to_result()?; Ok(()) } } /// Sets the preferred shared memory configuration for the current context. /// /// On devices with configurable shared memory banks, this function will set the context's /// shared memory bank size which is used for subsequent kernel launches. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext, SharedMemoryConfig }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// CurrentContext::set_shared_memory_config(SharedMemoryConfig::DefaultBankSize)?; /// # Ok(()) /// # } /// ``` pub fn set_shared_memory_config(cfg: SharedMemoryConfig) -> CudaResult<()> { unsafe { cuda::cuCtxSetSharedMemConfig(transmute(cfg)).to_result() } } /// Returns a non-owning handle to the current context. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// let unowned = CurrentContext::get_current()?; /// # Ok(()) /// # } /// ``` pub fn get_current() -> CudaResult<UnownedContext> { unsafe { let mut ctx: CUcontext = ptr::null_mut(); cuda::cuCtxGetCurrent(&mut ctx as *mut CUcontext).to_result()?; Ok(UnownedContext { inner: ctx }) } } /// Set the given context as the current context for this thread. /// /// If there is no context set for this thread, this pushes the given context onto the stack. /// If there is a context set for this thread, this replaces the top context on the stack with /// the given context. /// /// # Example /// /// ``` /// # use rustacuda::device::Device; /// # use rustacuda::context::{ Context, ContextFlags, CurrentContext }; /// # use std::error::Error; /// # /// # fn main () -> Result<(), Box<dyn Error>> { /// # rustacuda::init(rustacuda::CudaFlags::empty())?; /// # let device = Device::get_device(0)?; /// let context = Context::create_and_push(ContextFlags::MAP_HOST | ContextFlags::SCHED_AUTO, device)?; /// CurrentContext::set_current(&context)?; /// # Ok(()) /// # } /// ``` pub fn set_current<C: ContextHandle>(c: &C) -> CudaResult<()> { unsafe { cuda::cuCtxSetCurrent(c.get_inner()).to_result()?; Ok(()) } } /// Block to wait for a context's tasks to complete. pub fn synchronize() -> CudaResult<()> { unsafe { cuda::cuCtxSynchronize().to_result()?; Ok(()) } } }