fix more bugs to make the layers run in the model

fmoe/fmoe_functions.py

@@ -13,10 +13,13 @@ def moe_prepare_forward(gate, num_expert, world_size):
                 device=gate.device, dtype=torch.long)
         local_expert_count.index_put_((gate_idx.long(), ), gate_count)
 
-        global_expert_count, = fmoe_cuda.expert_exchange(
-                local_expert_count, num_expert, world_size)
+        if world_size > 1:
+            global_expert_count, = fmoe_cuda.expert_exchange(
+                    local_expert_count, num_expert, world_size)
+        else:
+            global_expert_count = local_expert_count
         fwd_expert_count = global_expert_count.view(world_size, 
-               num_expert).sum(dim=0).cpu()
+               num_expert).sum(dim=0)
         fwd_batch_size = int(fwd_expert_count.sum().item())
     return (pos, local_expert_count.cpu(), global_expert_count.cpu(), 
             fwd_expert_count.cpu(), fwd_batch_size)
@@ -35,6 +38,7 @@ class MOEScatter(Function):
             global_input_buf = local_input_buf
         ctx.moe_args = fwd_batch_size, inp.shape[0], world_size
         variables = (pos, local_expert_count, global_expert_count)
+        ctx.save_for_backward(*variables)
         return global_input_buf
 
     @staticmethod
@@ -57,14 +61,14 @@ class MOELinear(Function):
     def forward(ctx, global_input_buf, weight, fwd_expert_count):
         global_output_buf, = fmoe_cuda.forward(global_input_buf, weight,
                 fwd_expert_count)
-        variables = (input_buf, weight, fwd_expert_count)
+        variables = (global_input_buf, weight, fwd_expert_count)
         ctx.save_for_backward(*variables)
         return global_output_buf
 
     @staticmethod
     def backward(ctx, grad_out):
         (input_buf, weight, fwd_expert_count) = ctx.saved_tensors
-        grad_inp_buf, grad_weight = ome_cuda.backward(
+        grad_inp_buf, grad_weight = fmoe_cuda.backward(
                 grad_out, input_buf, weight, fwd_expert_count)
         return grad_inp_buf, grad_weight, None
 
@@ -81,7 +85,7 @@ class MOEGather(Function):
             local_output_buf = global_output_buf
         output, = fmoe_cuda.local_scatter(local_output_buf, pos)
 
-        ctx.moe_args = fwd_batch_size, world_size
+        ctx.moe_args = local_batch_size, global_output_buf.shape[0], world_size
         variables = (pos, local_expert_count, global_expert_count)
         ctx.save_for_backward(*variables)
         return output
@@ -89,8 +93,8 @@ class MOEGather(Function):
     @staticmethod
     def backward(ctx, grad_out):
         pos, local_expert_count, global_expert_count = ctx.saved_tensors
-        fwd_batch_size, world_size = ctx.moe_args
-        grad_out_buf = fmoe_cuda.local_gather(grad_out.contiguous(), pos)
+        local_batch_size, fwd_batch_size, world_size = ctx.moe_args
+        grad_out_buf, = fmoe_cuda.local_gather(grad_out.contiguous(), pos)
         if world_size > 1:
             global_grad_out_buf, = fmoe_cuda.global_scatter(grad_out_buf,
                     local_expert_count, global_expert_count,

fmoe/layers.py

@@ -49,7 +49,7 @@ def _fmoe_full_forward(inp, gate, linears, activation, num_expert, world_size):
     for i, l in enumerate(linears):
         if i:
             x = activation(x)
-        x = l(x)
+        x = l(x, fwd_expert_count)
     x = MOEGather.apply(x, pos, local_expert_count, global_expert_count,
             inp.shape[0], world_size)
     return x
@@ -78,16 +78,15 @@ class FMoETransformerMLP(nn.Module):
                 dtype=torch.float32)) 
 
     def forward(self, inp):
-        # import pdb; pdb.set_trace()
         residual = inp
         if self.pre_lnorm:
             inp = self.layer_norm(inp)
 
-        inp = inp.view(-1, self.d_model).repeat_interleave(repeats=self.top_k, 
-                dim=0) # (BxLxtop_k) x d_model
-
         gate_top_k_idx, gate_score = self.gate(inp)
 
+        # TODO: merge replication into local_scatter
+        inp = inp.view(-1, self.d_model).repeat_interleave(repeats=self.top_k, 
+                dim=0) # (BxLxtop_k) x d_model
         x = _fmoe_full_forward(inp, gate_top_k_idx, 
                 [self.htoh4, self.h4toh], self.activation,
                 self.num_expert, self.world_size)