File size: 6,510 Bytes
19886eb ab0f9c6 19886eb ab0f9c6 19886eb ab0f9c6 19886eb ab0f9c6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 | //! CUDA backend: cudarc driver API + the sm_120a cubins produced by build.rs (embedded in the binary).
use crate::backend::{Arg, Backend};
use anyhow::{anyhow, Result};
use cudarc::driver::{CudaContext, CudaFunction, CudaModule, CudaSlice, CudaStream, DevicePtr, LaunchConfig, PushKernelArg};
use cudarc::nvrtc::Ptx;
use std::collections::HashMap;
use std::sync::{Arc, Mutex};
include!(concat!(env!("OUT_DIR"), "/kernel_index.rs"));
pub struct CudaBackend {
pub ctx: Arc<CudaContext>,
pub stream: Arc<CudaStream>,
modules: HashMap<&'static str, Arc<CudaModule>>,
funcs: Mutex<HashMap<String, CudaFunction>>,
allocs: Mutex<HashMap<u64, CudaSlice<u8>>>,
/// second stream for an independent branch (dense-MLP || router+MoE): fork/use/join through events (also valid inside graph capture)
stream2: Arc<CudaStream>,
ev_fork: cudarc::driver::CudaEvent,
ev_join: cudarc::driver::CudaEvent,
on_branch: std::sync::atomic::AtomicBool,
}
impl CudaBackend {
pub fn new(ordinal: usize) -> Result<Arc<Self>> {
if KERNEL_FILES.is_empty() {
return Err(anyhow!("dllm-kernels was built without nvcc: no device code available (set NVCC=/path/to/nvcc and rebuild)"));
}
let ctx = CudaContext::new(ordinal)?;
unsafe { ctx.disable_event_tracking() }; // explicit fork/join events only (branch_fork / branch_join)
// a dedicated (non-default) stream: the legacy default stream cannot be captured into CUDA graphs
let stream = ctx.new_stream()?;
let mut modules = HashMap::new();
for (name, cubin) in KERNEL_FILES {
modules.insert(*name, ctx.load_module(Ptx::from_binary(cubin.to_vec()))?);
}
let stream2 = ctx.new_stream()?;
let flags = Some(cudarc::driver::sys::CUevent_flags::CU_EVENT_DISABLE_TIMING);
let (ev_fork, ev_join) = (ctx.new_event(flags)?, ctx.new_event(flags)?);
Ok(Arc::new(CudaBackend { stream2, ev_fork, ev_join, on_branch: std::sync::atomic::AtomicBool::new(false), ctx, stream, modules, funcs: Mutex::new(HashMap::new()), allocs: Mutex::new(HashMap::new()) }))
}
#[inline]
fn cur(&self) -> &Arc<CudaStream> {
if self.on_branch.load(std::sync::atomic::Ordering::Relaxed) { &self.stream2 } else { &self.stream }
}
fn func(&self, file: &str, sym: &str) -> Result<CudaFunction> {
let key = format!("{file}::{sym}");
let mut f = self.funcs.lock().unwrap();
if let Some(x) = f.get(&key) {
return Ok(x.clone());
}
let m = self.modules.get(file).ok_or_else(|| anyhow!("module {file} not built"))?;
let func = m.load_function(sym).map_err(|e| anyhow!("{file}::{sym}: {e}"))?;
f.insert(key, func.clone());
Ok(func)
}
}
impl Backend for CudaBackend {
fn name(&self) -> &'static str {
"cuda"
}
fn alloc(&self, bytes: usize) -> Result<u64> {
let s = self.stream.alloc_zeros::<u8>(bytes)?;
let p = s.device_ptr(&self.stream).0;
self.allocs.lock().unwrap().insert(p, s);
Ok(p)
}
fn free(&self, ptr: u64) {
self.allocs.lock().unwrap().remove(&ptr);
}
fn upload(&self, dst: u64, src: &[u8]) -> Result<()> {
let mut a = self.allocs.lock().unwrap();
// dst may point inside an allocation: find the owner
let (base, s) = a.iter_mut().find(|(b, s)| **b <= dst && dst < **b + s.len() as u64).ok_or_else(|| anyhow!("upload: unknown device pointer"))?;
let off = (dst - *base) as usize;
let mut view = s.slice_mut(off..off + src.len());
self.stream.memcpy_htod(src, &mut view)?;
Ok(())
}
fn download(&self, src: u64, dst: &mut [u8]) -> Result<()> {
let a = self.allocs.lock().unwrap();
let (base, s) = a.iter().find(|(b, s)| **b <= src && src < **b + s.len() as u64).ok_or_else(|| anyhow!("download: unknown device pointer"))?;
let off = (src - *base) as usize;
let view = s.slice(off..off + dst.len());
self.stream.memcpy_dtoh(&view, dst)?;
self.stream.synchronize()?;
Ok(())
}
fn copy_d2d(&self, dst: u64, src: u64, bytes: usize) -> Result<()> {
unsafe { cudarc::driver::result::memcpy_dtod_async(dst, src, bytes, self.stream.cu_stream())? };
Ok(())
}
fn memset0(&self, dst: u64, bytes: usize) -> Result<()> {
unsafe { cudarc::driver::result::memset_d8_async(dst, 0, bytes, self.stream.cu_stream())? };
Ok(())
}
fn launch(&self, file: &str, sym: &str, grid: [u32; 3], block: [u32; 3], args: &[Arg]) -> Result<()> {
let f = self.func(file, sym)?;
let cfg = LaunchConfig { grid_dim: (grid[0], grid[1], grid[2]), block_dim: (block[0], block[1], block[2]), shared_mem_bytes: 0 };
let mut b = self.cur().launch_builder(&f);
for a in args {
match a {
Arg::P(v) => b.arg(v),
Arg::I(v) => b.arg(v),
Arg::F(v) => b.arg(v),
Arg::L(v) => b.arg(v),
};
}
unsafe { b.launch(cfg) }.map_err(|e| anyhow!("launch {file}::{sym}: {e}"))?;
Ok(())
}
fn branch_fork(&self) -> Result<()> {
self.ev_fork.record(&self.stream)?;
self.stream2.wait(&self.ev_fork)?;
Ok(())
}
fn branch_use(&self, on: bool) {
self.on_branch.store(on, std::sync::atomic::Ordering::Relaxed);
}
fn branch_join(&self) -> Result<()> {
self.ev_join.record(&self.stream2)?;
self.stream.wait(&self.ev_join)?;
Ok(())
}
fn sync(&self) -> Result<()> {
self.stream.synchronize()?;
Ok(())
}
fn graph_begin(&self) -> Result<()> {
self.stream.begin_capture(cudarc::driver::sys::CUstreamCaptureMode::CU_STREAM_CAPTURE_MODE_THREAD_LOCAL)?;
Ok(())
}
fn graph_end(&self) -> Result<Box<dyn crate::backend::GraphExec>> {
let g = self.stream.end_capture(cudarc::driver::sys::CUgraphInstantiate_flags(0))?.ok_or_else(|| anyhow!("empty CUDA graph"))?;
Ok(Box::new(CudaGraphExec(g)))
}
}
struct CudaGraphExec(cudarc::driver::CudaGraph);
// the graph is only ever launched from the engine thread that captured it; the handle itself is a plain driver object
unsafe impl Send for CudaGraphExec {}
unsafe impl Sync for CudaGraphExec {}
impl crate::backend::GraphExec for CudaGraphExec {
fn launch(&self) -> Result<()> {
self.0.launch()?;
Ok(())
}
}
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