rich7420 commented on code in PR #708:
URL: https://github.com/apache/mahout/pull/708#discussion_r2616347482
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qdp/qdp-core/src/gpu/memory.rs:
##########
@@ -263,3 +266,79 @@ impl GpuStateVector {
}
}
}
+
+// === Pinned Memory Implementation ===
+
+/// Pinned Host Memory Buffer (Page-Locked)
+///
+/// Enables DMA for H2D copies, doubling bandwidth and reducing CPU usage.
+#[cfg(target_os = "linux")]
+pub struct PinnedBuffer {
+ ptr: *mut f64,
+ size_elements: usize,
+}
+
+#[cfg(target_os = "linux")]
+impl PinnedBuffer {
+ /// Allocate pinned memory
+ pub fn new(elements: usize) -> Result<Self> {
+ unsafe {
+ let bytes = elements * std::mem::size_of::<f64>();
+ let mut ptr: *mut c_void = std::ptr::null_mut();
+
+ unsafe extern "C" {
+ fn cudaHostAlloc(pHost: *mut *mut c_void, size: usize, flags:
u32) -> i32;
+ }
+
+ let ret = cudaHostAlloc(&mut ptr, bytes, 0); //
cudaHostAllocDefault
+
+ if ret != 0 {
+ return Err(MahoutError::MemoryAllocation(
+ format!("cudaHostAlloc failed with error code: {}", ret)
+ ));
+ }
+
+ Ok(Self {
+ ptr: ptr as *mut f64,
+ size_elements: elements,
+ })
+ }
+ }
+
+ /// Get mutable slice to write data into
+ pub fn as_slice_mut(&mut self) -> &mut [f64] {
+ unsafe { std::slice::from_raw_parts_mut(self.ptr, self.size_elements) }
+ }
+
+ /// Get raw pointer for CUDA memcpy
+ pub fn ptr(&self) -> *const f64 {
+ self.ptr
+ }
+
+ pub fn len(&self) -> usize {
+ self.size_elements
+ }
+
+ pub fn is_empty(&self) -> bool {
+ self.size_elements == 0
+ }
+}
+
+#[cfg(target_os = "linux")]
+impl Drop for PinnedBuffer {
+ fn drop(&mut self) {
+ unsafe {
+ unsafe extern "C" {
+ fn cudaFreeHost(ptr: *mut c_void) -> i32;
+ }
+ let _ = cudaFreeHost(self.ptr as *mut c_void);
Review Comment:
sure!
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