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tinygrad/extra/thunder/cuda/include/ops/group/group.cuh
2025-10-27 17:19:53 -07:00

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/**
* @file
* @brief An aggregate header of all group (multi-warp) operations defined by ThunderKittens
*/
#pragma once
#include <cuda/pipeline>
#include "../../common/common.cuh"
#include "../../types/types.cuh"
#include "../thread/thread.cuh" // several group memory ops rely on underlying warp-scope ops
#define KITTENS_CHECK_WARP static_assert(GROUP_WARPS==1, "Warp (GROUP_WARPS=1) function called from a non-warp group.");
// A "warpgroup" is a special group of 4 consecutive warps defined by NVIDIA for certain SM_90+ operations.
#define KITTENS_CHECK_WARPGROUP static_assert(GROUP_WARPS==4, "Warpgroup (GROUP_WARPS=4) function called from a non-warpgroup group.");
// WGMMA relies on some template structures that cannot be specialized within the group struct, so we declare them in advance.
#ifdef KITTENS_HOPPER
#include "mma/warpgroup/base/base.cuh"
#endif
namespace kittens {
/*
This is meant to be used with a `using group_N = kittens::group<NUM_WORKERS>;` at the start of every kernel.
*/
template<int _GROUP_WARPS>
struct group {
static constexpr int GROUP_WARPS = _GROUP_WARPS; // This alias produces nice parallelism.
static constexpr int GROUP_THREADS = GROUP_WARPS * kittens::WARP_THREADS; // This alias produces nice parallelism.
__device__ static inline int laneid() { return threadIdx.x % GROUP_THREADS; }
__device__ static inline int warpid() { return laneid() / kittens::WARP_THREADS; }
__device__ static inline int groupid() { return threadIdx.x / GROUP_THREADS; }
__device__ static inline void sync(int id) {
asm volatile("bar.sync %0, %1;\n" :: "r"(id), "n"(GROUP_THREADS));
}
template<uint32_t MASK=0xFFFFFFFF> __device__ static inline void sync() {
static_assert(GROUP_WARPS==1, "barrier-less sync() can only be called by a single warp!");
asm volatile("bar.warp.sync %0;\n" :: "n"(MASK));
}
__device__ static inline void arrive(int id) {
asm volatile("bar.arrive %0, %1;\n" :: "r"(id), "n"(GROUP_THREADS));
}
#include "memory/memory.cuh"
#include "shared/shared.cuh"
#include "register/register.cuh"
#include "mma/mma.cuh"
#ifdef KITTENS_HOPPER
template<int n_reg> __device__ static inline void increase_registers() {
static_assert(n_reg % 8 == 0, "n_reg must be a multiple of 8");
asm volatile("setmaxnreg.inc.sync.aligned.u32 %0;\n" :: "n"(n_reg));
}
template<int n_reg> __device__ static inline void decrease_registers() {
static_assert(n_reg % 8 == 0, "n_reg must be a multiple of 8");
asm volatile("setmaxnreg.dec.sync.aligned.u32 %0;\n" :: "n"(n_reg));
}
__device__ static inline void producer_registers() { decrease_registers<24>(); }
template<int NCWG> __device__ static inline void consumer_registers() { increase_registers<480/NCWG - 8*(NCWG>3) - 224*(NCWG==1)>(); }
#endif
};
namespace everyone {
// Block-level synchronization
__device__ static inline void sync(int id) {
asm volatile("bar.sync %0;\n" :: "r"(id));
}
// Cluster-level synchronization functions
namespace tma {
namespace cluster {
__device__ static inline void arrive_aligned() { // All threads in the cluster must call this
asm volatile ("barrier.cluster.arrive.release.aligned;\n");
}
__device__ static inline void wait_aligned() {
asm volatile ("barrier.cluster.wait.acquire.aligned;\n");
}
__device__ static inline void sync() {
arrive_aligned();
wait_aligned();
}
}
}
};
using warp = group<1>; // scope used by most pre-Hopper GPUs, and also for most register operations.
using warpgroup = group<4>; // special scope commonly used by Hopper and later.
}