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work on abstractions4 (#15671)
* work on abstractions4 * works * offst * assembly works * RAND * cleanup * work
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docs/abstractions4.py
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187
docs/abstractions4.py
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# tinygrad allows you to write kernels at many different abstractions levels.
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# This is for RDNA3, but if you don't have one you can run with the emulator
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# PYTHONPATH="." MOCKGPU=1 DEV=AMD
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from tinygrad import Tensor, Context, GlobalCounters, UOp, Device
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from tinygrad.helpers import DEBUG, getenv
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from tinygrad.uop.ops import AxisType, KernelInfo, Ops
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from tinygrad.dtype import AddrSpace, dtypes
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SZ = 32*1024 if getenv("MOCKGPU") else 1024*1024*1024
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if __name__ == "__main__":
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correct = None
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# First define a Tensor and realize it. We will focus on a 1GB sum kernel on RDNA3
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a = (Tensor.randn(SZ) if getenv("RAND") else Tensor.ones(SZ)).contiguous().realize()
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def eval_harness(name, fxn, check=None):
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print(f"***** {name}")
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GlobalCounters.reset()
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with Context(DEBUG=max(DEBUG.value, 2)): out = fxn(a).item()
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assert check is None or abs(out - check) < abs(check) * 1e-3, f"out was wrong {out}, expected {check}, off by {out/check}x"
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print(f"computed in {GlobalCounters.time_sum_s*1000:.2f} ms, {(a.nbytes()/1e9)/GlobalCounters.time_sum_s:.2f} GB/s")
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return out
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if not getenv("ASM"):
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# *****
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# This is the high level tinygrad way.
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# Note that this is split into multiple kernels for speed.
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correct = eval_harness("basic kernel", lambda x: x.sum())
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# *****
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# Now we get to the lower abstraction layers.
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# You can write a kernel in UOps, and it's 2.5x faster.
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# This GPU has 32 CUs, keep them all busy
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CU_COUNT = 32
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def custom_sum(out:UOp, buf:UOp) -> UOp:
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LCLS = 256
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buf = buf.reshape(CU_COUNT, -1, LCLS)
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glbl = UOp.range(CU_COUNT, 0, AxisType.GLOBAL)
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lane = UOp.range(LCLS, 1, AxisType.LOCAL)
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# accumulate the globals into a per lane accumulator
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reduce_loop = UOp.range(buf.shape[1], 2, AxisType.REDUCE)
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acc = UOp.placeholder((1,), dtypes.float, slot=6, addrspace=AddrSpace.REG)
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acc = acc.after(acc.store(0))
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acc = acc.after(acc[0].store(acc.after(reduce_loop)[0] + buf[glbl, reduce_loop, lane]).end(reduce_loop))
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# store all the per lane accumulators to LOCAL
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local_accs = UOp.placeholder((LCLS,), dtypes.float, slot=0, addrspace=AddrSpace.LOCAL)
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local_accs = local_accs.after(local_accs[lane].store(acc[0]).barrier())
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# accumulate LOCALs into a single per CU accumulator
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late_reduce_loop = UOp.range(LCLS, 3, AxisType.REDUCE)
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acc2 = UOp.placeholder((1,), dtypes.float, slot=7, addrspace=AddrSpace.REG)
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acc2 = acc2.after(acc2.store(0))
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acc2 = acc2.after(acc2[0].store(acc2.after(late_reduce_loop)[0] + local_accs[late_reduce_loop]).end(late_reduce_loop))[0]
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# store (NOTE: since the address doesn't depend on the warp, this will be automatically gated)
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return out[glbl].store(acc2).end(lane, glbl).sink(arg=KernelInfo(opts_to_apply=()))
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eval_harness("custom UOp kernel", lambda x: Tensor.empty(CU_COUNT).custom_kernel(x, fxn=custom_sum)[0].sum(), check=correct)
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# *****
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# You can also BEAM search stock tinygrad for a faster kernel.
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# This does even better than the custom kernel in this simple case.
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with Context(BEAM=2): eval_harness("BEAMed kernel", lambda x: x.sum(), check=correct)
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# *****
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# Though if you really want to go crazy with speed, you can code in assembly
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# Kernel class copied from amd_asm_matmul
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class Kernel:
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def __init__(self, arch='gfx1100'): self.instructions, self.labels, self.pos, self.arch = [], {}, 0, arch
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def label(self, name): self.labels[name] = self.pos
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def emit(self, inst, target=None):
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self.instructions.append(inst)
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inst._target, inst._pos = target, self.pos
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self.pos += inst.size()
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return inst
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def waitcnt(self, lgkm=None, vm=None):
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# Wait for memory operations. lgkm=N waits until N lgkm ops remain, vm=N waits until N vmem ops remain.
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vmcnt, lgkmcnt, expcnt = vm if vm is not None else 63, lgkm if lgkm is not None else 63, 7
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waitcnt = (expcnt & 0x7) | ((lgkmcnt & 0x3f) << 4) | ((vmcnt & 0x3f) << 10)
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self.emit(s_waitcnt(simm16=waitcnt))
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def finalize(self, sink:UOp) -> UOp:
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for inst in self.instructions:
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if inst._target is None: continue
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offset_dwords = (self.labels[inst._target] - inst._pos - inst.size()) // 4
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if not -32768 <= offset_dwords <= 32767: raise ValueError(f"branch to '{inst._target}' offset {offset_dwords} exceeds simm16 range")
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inst.simm16 = offset_dwords
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return UOp(Ops.PROGRAM, src=(sink, UOp(Ops.DEVICE, arg=Device.DEFAULT),
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UOp(Ops.LINEAR, src=tuple([UOp(Ops.INS, arg=x) for x in self.instructions]))))
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from tinygrad.runtime.autogen.amd.rdna3.ins import *
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CU_COUNT = 32
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LANES = 64
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def asm_sum(out:UOp, buf:UOp) -> UOp:
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V_LANE_ID = 0 # lane_id set on startup
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S_WORKGROUP_X = 2 # workgroup_id_x
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S_LOOP_CTR = 3
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k = Kernel()
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# mul lane id by 16 for offsets (4 for float, 4 for b128)
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k.emit(v_mul_lo_u32(v[0], v[V_LANE_ID], 16))
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k.emit(v_add_nc_u32_e32(v[1], 4096, v[0]))
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k.emit(v_add_nc_u32_e32(v[2], 4096, v[1]))
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k.emit(v_add_nc_u32_e32(v[3], 4096, v[2]))
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# load both addresses
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k.emit(s_load_b128(sdata=s[4:7], sbase=s[0:1], offset=0x0, soffset=NULL))
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k.waitcnt(lgkm=0)
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# offset buffer pointer by workgroup_id_x * chunk_size_bytes
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k.emit(s_mul_i32(s[S_LOOP_CTR], s[S_WORKGROUP_X], buf.numel()*4//CU_COUNT))
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k.emit(s_add_u32(s[6], s[6], s[S_LOOP_CTR]))
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k.emit(s_addc_u32(s[7], s[7], 0))
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# zero the accumulators
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k.emit(VOPD(VOPDOp.V_DUAL_MOV_B32, VOPDOp.V_DUAL_MOV_B32, vdstx=v[4], vdsty=v[5], srcx0=0, srcy0=0))
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k.emit(VOPD(VOPDOp.V_DUAL_MOV_B32, VOPDOp.V_DUAL_MOV_B32, vdstx=v[6], vdsty=v[7], srcx0=0, srcy0=0))
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def emit_loads(base_vreg, reg_len):
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assert reg_len%4 == 0
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k.emit(s_clause(simm16=(reg_len//4)-1))
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for i in range(reg_len//4):
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offset = i*LANES*16
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assert offset < 16384
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k.emit(global_load_b128(vdst=v[base_vreg+i*4:base_vreg+i*4+3], addr=v[offset//4096], saddr=s[6:7], offset=offset%4096))
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k.emit(s_add_u32(s[6], s[6], reg_len * LANES * 4))
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k.emit(s_addc_u32(s[7], s[7], 0))
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def tree_reduce_to_4567(base_vreg, reg_len):
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assert reg_len%4 == 0
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reg_len //= 4
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while reg_len > 1:
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half = reg_len // 2
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for j in range(half):
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a, b = base_vreg + j*4, base_vreg + (j+half)*4
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# v[a+0](bank0) += v[b+2](bank2), v[a+1](bank1) += v[b+3](bank3) — src0 and src1 on different banks
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k.emit(VOPD(VOPDOp.V_DUAL_ADD_F32, VOPDOp.V_DUAL_ADD_F32, vdstx=v[a], vdsty=v[a+1], srcx0=v[a], vsrcx1=v[b+2], srcy0=v[a+1], vsrcy1=v[b+3]))
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# v[a+2](bank2) += v[b+0](bank0), v[a+3](bank3) += v[b+1](bank1) — src0 and src1 on different banks
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k.emit(VOPD(VOPDOp.V_DUAL_ADD_F32, VOPDOp.V_DUAL_ADD_F32, vdstx=v[a+2], vdsty=v[a+3], srcx0=v[a+2], vsrcx1=v[b], srcy0=v[a+3], vsrcy1=v[b+1]))
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reg_len = half
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k.emit(VOPD(VOPDOp.V_DUAL_ADD_F32, VOPDOp.V_DUAL_ADD_F32, vdstx=v[4], vdsty=v[5], srcx0=v[4], vsrcx1=v[base_vreg], srcy0=v[5], vsrcy1=v[base_vreg+1]))
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k.emit(VOPD(VOPDOp.V_DUAL_ADD_F32, VOPDOp.V_DUAL_ADD_F32, vdstx=v[6], vdsty=v[7], srcx0=v[6], vsrcx1=v[base_vreg+2], srcy0=v[7], vsrcy1=v[base_vreg+3]))
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BASE_REG = 8
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LOAD_UNROLL = 64
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INNER_UNROLL = 2
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assert buf.numel() % (CU_COUNT*LANES*LOAD_UNROLL*INNER_UNROLL) == 0
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total_batches = buf.numel()//(CU_COUNT*LANES*LOAD_UNROLL*INNER_UNROLL)
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k.emit(s_mov_b32(s[S_LOOP_CTR], total_batches-1))
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k.label('LOOP')
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for _ in range(INNER_UNROLL):
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emit_loads(BASE_REG, reg_len=LOAD_UNROLL)
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k.waitcnt(vm=0)
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tree_reduce_to_4567(BASE_REG, reg_len=LOAD_UNROLL)
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k.emit(s_sub_u32(s[S_LOOP_CTR], s[S_LOOP_CTR], 1))
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k.emit(s_cbranch_scc0(), target='LOOP')
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# add into v[4]
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k.emit(v_add_f32_e32(v[4], v[4], v[5]))
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k.emit(v_add_f32_e32(v[6], v[6], v[7]))
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k.emit(v_add_f32_e32(v[4], v[4], v[6]))
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# warp shuffle into v[4] on lane 0 using DPP row_shl within each 16-lane row
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for shift in [1, 2, 4, 8]:
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k.emit(v_add_f32_e32(v[4], DPP, v[4], vsrc0=v[4], dpp=0x100 | shift, row_mask=0xf, bank_mask=0xf, bc=1))
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# combine rows: get lane 16's value to lane 0 via permlanex16
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k.emit(v_permlanex16_b32(v[5], v[4], 0, 0))
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k.emit(v_add_f32_e32(v[4], v[4], v[5]))
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# atomic store (only on lane 0)
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k.emit(s_mov_b32(EXEC_LO, 1))
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k.emit(v_mov_b32_e32(v[0], 0))
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k.emit(global_atomic_add_f32(addr=v[0], saddr=s[4:5], data=v[4]))
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k.emit(s_sendmsg(simm16=3)) # DEALLOC_VGPRS
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k.emit(s_endpgm())
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return k.finalize(UOp.sink(UOp.special(CU_COUNT, 'gidx0'), UOp.special(LANES, 'lidx0'), out, buf,
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arg=KernelInfo(name="asm_reduce", opts_to_apply=())))
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out = Tensor.zeros(1,).contiguous().realize()
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eval_harness("RDNA3 assembly kernel", lambda x: out.custom_kernel(x, fxn=asm_sum)[0], check=correct)
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