From 4f5e4540f88d3d8d933cef30547b587c17ed52f1 Mon Sep 17 00:00:00 2001
From: Adam <38704900+grygielski@users.noreply.github.com>
Date: Mon, 23 Mar 2020 09:59:42 +0100
Subject: [PATCH] Improve SGD jit code to work with large data (#23120)

---
 paddle/fluid/operators/jit/gen/sgd.cc | 83 ++++++++++++++-------------
 paddle/fluid/operators/jit/gen/sgd.h  |  1 +
 2 files changed, 43 insertions(+), 41 deletions(-)

diff --git a/paddle/fluid/operators/jit/gen/sgd.cc b/paddle/fluid/operators/jit/gen/sgd.cc
index e65d3500b49..40f8298af39 100644
--- a/paddle/fluid/operators/jit/gen/sgd.cc
+++ b/paddle/fluid/operators/jit/gen/sgd.cc
@@ -24,22 +24,41 @@ namespace operators {
 namespace jit {
 namespace gen {
 
+void SgdJitCode::mainCode(int num_regs) {
+  constexpr size_t block_size = sizeof(float) * YMM_FLOAT_BLOCK;
+  // load grad
+  for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
+    vmovups(ymm_t(reg_i), ptr[reg_ptr_grad_i]);
+    add(reg_ptr_grad_i, block_size);
+  }
+  // load param
+  for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
+    vmovups(ymm_t(reg_i + num_regs), ptr[reg_ptr_param_i]);
+    add(reg_ptr_param_i, block_size);
+  }
+  // compute out
+  for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
+    vmulps(ymm_t(reg_i), ymm_t(reg_i), ymm_lr);
+    vsubps(ymm_t(reg_i + num_regs), ymm_t(reg_i + num_regs), ymm_t(reg_i));
+  }
+  // save out
+  for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
+    vmovups(ptr[reg_ptr_out_i], ymm_t(reg_i + num_regs));
+    add(reg_ptr_out_i, block_size);
+  }
+}
+
 void SgdJitCode::genCode() {
   preCode();
   constexpr int block = YMM_FLOAT_BLOCK;
   constexpr int max_num_regs = 7;
   const int num_block = w_ / block;
   const int num_groups = num_block / max_num_regs;
-  const size_t block_size = sizeof(float) * block;
-  const size_t width_size = w_ * sizeof(float);
-  std::vector<int> groups(num_groups, max_num_regs);
   int rest_num_regs = num_block % max_num_regs;
-  if (rest_num_regs > 0) {
-    groups.push_back(rest_num_regs);
-  }
+  const size_t width_size = w_ * sizeof(float);
 
   vbroadcastss(ymm_lr, ptr[param_lr]);
-  // protect rdx
+
   mov(reg_ptr_grad_i, param_grad);
   mov(reg_ptr_rows_i, param_rows);
 
@@ -63,43 +82,27 @@ void SgdJitCode::genCode() {
     add(reg_ptr_param_i, reg_row);
     add(reg_ptr_out_i, reg_row);
 
-    size_t w_offset = 0;
-    for (int num_regs : groups) {
-      // load grad
-      size_t inner_offfset = w_offset;
-      for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
-        vmovups(ymm_t(reg_i), ptr[reg_ptr_grad_i + inner_offfset]);
-        inner_offfset += block_size;
-      }
-
-      // load param
-      inner_offfset = w_offset;
-      for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
-        vmovups(ymm_t(reg_i + num_regs), ptr[reg_ptr_param_i + inner_offfset]);
-        inner_offfset += block_size;
-      }
-
-      // compute out
-      for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
-        vmulps(ymm_t(reg_i), ymm_t(reg_i), ymm_lr);
-        vsubps(ymm_t(reg_i + num_regs), ymm_t(reg_i + num_regs), ymm_t(reg_i));
-      }
-
-      // save out
-      inner_offfset = w_offset;
-      for (int reg_i = 0; reg_i < num_regs; ++reg_i) {
-        vmovups(ptr[reg_ptr_out_i + inner_offfset], ymm_t(reg_i + num_regs));
-        inner_offfset += block_size;
-      }
-      w_offset += (block_size * num_regs);
+    Label inner_loop;
+    Label escape_loop;
+    mov(rax, 0);
+    L(inner_loop);
+    {
+      cmp(rax, num_groups);
+      jnb(escape_loop, T_NEAR);
+
+      mainCode(max_num_regs);
+
+      inc(rax);
+      jmp(inner_loop, T_NEAR);
     }
+    L(escape_loop);
+    mainCode(rest_num_regs);
 
-    add(reg_ptr_grad_i, width_size);
     add(reg_ptr_rows_i, sizeof(int64_t));
+
     cmp(reg_ptr_rows_i, reg_rows_size_in_byte);
     jl(l_next_row, T_NEAR);
   }
-
   postCode();
 }
 
@@ -109,9 +112,7 @@ class SgdCreator : public JitCodeCreator<sgd_attr_t> {
     return platform::MayIUse(platform::avx) &&
            attr.grad_width % YMM_FLOAT_BLOCK == 0;
   }
-  size_t CodeSize(const sgd_attr_t& attr) const override {
-    return 96 + (attr.grad_width / YMM_FLOAT_BLOCK) * 32 * 8;
-  }
+  size_t CodeSize(const sgd_attr_t& attr) const override { return 96 + 32 * 8; }
   std::unique_ptr<GenBase> CreateJitCode(
       const sgd_attr_t& attr) const override {
     PADDLE_ENFORCE_EQ(attr.param_width, attr.grad_width);
diff --git a/paddle/fluid/operators/jit/gen/sgd.h b/paddle/fluid/operators/jit/gen/sgd.h
index 317edcd2bcb..80b1809bbbf 100644
--- a/paddle/fluid/operators/jit/gen/sgd.h
+++ b/paddle/fluid/operators/jit/gen/sgd.h
@@ -34,6 +34,7 @@ class SgdJitCode : public JitCode {
 
   DECLARE_JIT_CODE(SgdJitCode);
   void genCode() override;
+  void mainCode(int num_regs);
 
  private:
   int w_;
-- 
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