Serialize expand entry for allgather. (#9702)

2023-10-24 14:33:28 +08:00
parent ee8b29c843
commit 7a02facc9d
14 changed files with 336 additions and 76 deletions
--- a/src/tree/gpu_hist/expand_entry.cuh
+++ b/src/tree/gpu_hist/expand_entry.cuh
@@ -1,31 +1,36 @@
-/*!
- * Copyright 2020 by XGBoost Contributors
+/**
+ * Copyright 2020-2023, XGBoost Contributors
 */
 #ifndef EXPAND_ENTRY_CUH_
 #define EXPAND_ENTRY_CUH_
-#include <xgboost/span.h>
+
+#include <limits>   // for numeric_limits
+#include <utility>  // for move

 #include "../param.h"
 #include "../updater_gpu_common.cuh"
+#include "xgboost/base.h"  // for bst_node_t

-namespace xgboost {
-namespace tree {
-
+namespace xgboost::tree {
 struct GPUExpandEntry {
-  int nid;
-  int depth;
+  bst_node_t nid;
+  bst_node_t depth;
  DeviceSplitCandidate split;

-  float base_weight { std::numeric_limits<float>::quiet_NaN() };
-  float left_weight { std::numeric_limits<float>::quiet_NaN() };
-  float right_weight { std::numeric_limits<float>::quiet_NaN() };
+  float base_weight{std::numeric_limits<float>::quiet_NaN()};
+  float left_weight{std::numeric_limits<float>::quiet_NaN()};
+  float right_weight{std::numeric_limits<float>::quiet_NaN()};

  GPUExpandEntry() = default;
-  XGBOOST_DEVICE GPUExpandEntry(int nid, int depth, DeviceSplitCandidate split,
-                             float base, float left, float right)
-      : nid(nid), depth(depth), split(std::move(split)), base_weight{base},
-        left_weight{left}, right_weight{right} {}
-  bool IsValid(const TrainParam& param, int num_leaves) const {
+  XGBOOST_DEVICE GPUExpandEntry(bst_node_t nid, bst_node_t depth, DeviceSplitCandidate split,
+                                float base, float left, float right)
+      : nid(nid),
+        depth(depth),
+        split(std::move(split)),
+        base_weight{base},
+        left_weight{left},
+        right_weight{right} {}
+  [[nodiscard]] bool IsValid(TrainParam const& param, bst_node_t num_leaves) const {
    if (split.loss_chg <= kRtEps) return false;
    if (split.left_sum.GetQuantisedHess() == 0 || split.right_sum.GetQuantisedHess() == 0) {
      return false;
@@ -42,17 +47,11 @@ struct GPUExpandEntry {
    return true;
  }

-  bst_float GetLossChange() const {
-    return split.loss_chg;
-  }
+  [[nodiscard]] float GetLossChange() const { return split.loss_chg; }

-  int GetNodeId() const {
-    return nid;
-  }
+  [[nodiscard]] bst_node_t GetNodeId() const { return nid; }

-  int GetDepth() const {
-    return depth;
-  }
+  [[nodiscard]] bst_node_t GetDepth() const { return depth; }

  friend std::ostream& operator<<(std::ostream& os, const GPUExpandEntry& e) {
    os << "GPUExpandEntry: \n";
@@ -63,9 +62,69 @@ struct GPUExpandEntry {
    os << "right_sum: " << e.split.right_sum << "\n";
    return os;
  }
-};

-}  // namespace tree
-}  // namespace xgboost
+  void Save(Json* p_out) const {
+    auto& out = *p_out;
+
+    out["nid"] = Integer{this->nid};
+    out["depth"] = Integer{this->depth};
+    // GPU specific
+    out["base_weight"] = this->base_weight;
+    out["left_weight"] = this->left_weight;
+    out["right_weight"] = this->right_weight;
+
+    /**
+     * Handle split
+     */
+    out["split"] = Object{};
+    auto& split = out["split"];
+    split["loss_chg"] = this->split.loss_chg;
+    split["sindex"] = Integer{this->split.findex};
+    split["split_value"] = this->split.fvalue;
+
+    // cat
+    split["thresh"] = Integer{this->split.thresh};
+    split["is_cat"] = Boolean{this->split.is_cat};
+    /**
+     * Gradients
+     */
+    auto save = [&](std::string const& name, GradientPairInt64 const& sum) {
+      out[name] = I64Array{2};
+      auto& array = get<I64Array>(out[name]);
+      array[0] = sum.GetQuantisedGrad();
+      array[1] = sum.GetQuantisedHess();
+    };
+    save("left_sum", this->split.left_sum);
+    save("right_sum", this->split.right_sum);
+  }
+
+  void Load(Json const& in) {
+    this->nid = get<Integer const>(in["nid"]);
+    this->depth = get<Integer const>(in["depth"]);
+    // GPU specific
+    this->base_weight = get<Number const>(in["base_weight"]);
+    this->left_weight = get<Number const>(in["left_weight"]);
+    this->right_weight = get<Number const>(in["right_weight"]);
+
+    /**
+     * Handle split
+     */
+    auto const& split = in["split"];
+    this->split.loss_chg = get<Number const>(split["loss_chg"]);
+    this->split.findex = get<Integer const>(split["sindex"]);
+    this->split.fvalue = get<Number const>(split["split_value"]);
+    // cat
+    this->split.thresh = get<Integer const>(split["thresh"]);
+    this->split.is_cat = get<Boolean const>(split["is_cat"]);
+    /**
+     * Gradients
+     */
+    auto const& left_sum = get<I64Array const>(in["left_sum"]);
+    this->split.left_sum = GradientPairInt64{left_sum[0], left_sum[1]};
+    auto const& right_sum = get<I64Array const>(in["right_sum"]);
+    this->split.right_sum = GradientPairInt64{right_sum[0], right_sum[1]};
+  }
+};
+}  // namespace xgboost::tree

 #endif  // EXPAND_ENTRY_CUH_
--- a/src/tree/hist/expand_entry.h
+++ b/src/tree/hist/expand_entry.h
@@ -1,16 +1,20 @@
 /**
- * Copyright 2021-2023 XGBoost contributors
+ * Copyright 2021-2023, XGBoost Contributors
 */
 #ifndef XGBOOST_TREE_HIST_EXPAND_ENTRY_H_
 #define XGBOOST_TREE_HIST_EXPAND_ENTRY_H_

-#include <algorithm>       // for all_of
-#include <ostream>         // for ostream
-#include <utility>         // for move
-#include <vector>          // for vector
+#include <algorithm>    // for all_of
+#include <ostream>      // for ostream
+#include <string>       // for string
+#include <type_traits>  // for add_const_t
+#include <utility>      // for move
+#include <vector>       // for vector

-#include "../param.h"      // for SplitEntry, SplitEntryContainer, TrainParam
-#include "xgboost/base.h"  // for GradientPairPrecise, bst_node_t
+#include "../../common/type.h"  // for EraseType
+#include "../param.h"           // for SplitEntry, SplitEntryContainer, TrainParam
+#include "xgboost/base.h"       // for GradientPairPrecise, bst_node_t
+#include "xgboost/json.h"       // for Json

 namespace xgboost::tree {
 /**
@@ -29,6 +33,66 @@ struct ExpandEntryImpl {
  [[nodiscard]] bool IsValid(TrainParam const& param, bst_node_t num_leaves) const {
    return static_cast<Impl const*>(this)->IsValidImpl(param, num_leaves);
  }
+
+  void Save(Json* p_out) const {
+    auto& out = *p_out;
+    auto self = static_cast<Impl const*>(this);
+
+    out["nid"] = Integer{this->nid};
+    out["depth"] = Integer{this->depth};
+
+    /**
+     * Handle split
+     */
+    out["split"] = Object{};
+    auto& split = out["split"];
+    split["loss_chg"] = self->split.loss_chg;
+    split["sindex"] = Integer{self->split.sindex};
+    split["split_value"] = self->split.split_value;
+
+    auto const& cat_bits = self->split.cat_bits;
+    auto s_cat_bits = common::Span{cat_bits.data(), cat_bits.size()};
+    split["cat_bits"] = U8Array{s_cat_bits.size_bytes()};
+    auto& j_cat_bits = get<U8Array>(split["cat_bits"]);
+    using T = typename decltype(self->split.cat_bits)::value_type;
+    auto erased =
+        common::EraseType<std::add_const_t<T>, std::add_const_t<std::uint8_t>>(s_cat_bits);
+    for (std::size_t i = 0; i < erased.size(); ++i) {
+      j_cat_bits[i] = erased[i];
+    }
+
+    split["is_cat"] = Boolean{self->split.is_cat};
+
+    self->SaveGrad(&split);
+  }
+
+  void Load(Json const& in) {
+    auto self = static_cast<Impl*>(this);
+
+    this->nid = get<Integer const>(in["nid"]);
+    this->depth = get<Integer const>(in["depth"]);
+
+    /**
+     * Handle split
+     */
+    auto const& split = in["split"];
+    self->split.loss_chg = get<Number const>(split["loss_chg"]);
+    self->split.sindex = get<Integer const>(split["sindex"]);
+    self->split.split_value = get<Number const>(split["split_value"]);
+
+    auto const& j_cat_bits = get<U8Array const>(split["cat_bits"]);
+    using T = typename decltype(self->split.cat_bits)::value_type;
+    auto restored = common::RestoreType<std::add_const_t<T>>(
+        common::Span{j_cat_bits.data(), j_cat_bits.size()});
+    self->split.cat_bits.resize(restored.size());
+    for (std::size_t i = 0; i < restored.size(); ++i) {
+      self->split.cat_bits[i] = restored[i];
+    }
+
+    self->split.is_cat = get<Boolean const>(split["is_cat"]);
+
+    self->LoadGrad(split);
+  }
 };

 struct CPUExpandEntry : public ExpandEntryImpl<CPUExpandEntry> {
@@ -39,6 +103,24 @@ struct CPUExpandEntry : public ExpandEntryImpl<CPUExpandEntry> {
      : ExpandEntryImpl{nidx, depth}, split(std::move(split)) {}
  CPUExpandEntry(bst_node_t nidx, bst_node_t depth) : ExpandEntryImpl{nidx, depth} {}

+  void SaveGrad(Json* p_out) const {
+    auto& out = *p_out;
+    auto save = [&](std::string const& name, GradStats const& sum) {
+      out[name] = F32Array{2};
+      auto& array = get<F32Array>(out[name]);
+      array[0] = sum.GetGrad();
+      array[1] = sum.GetHess();
+    };
+    save("left_sum", this->split.left_sum);
+    save("right_sum", this->split.right_sum);
+  }
+  void LoadGrad(Json const& in) {
+    auto const& left_sum = get<F32Array const>(in["left_sum"]);
+    this->split.left_sum = GradStats{left_sum[0], left_sum[1]};
+    auto const& right_sum = get<F32Array const>(in["right_sum"]);
+    this->split.right_sum = GradStats{right_sum[0], right_sum[1]};
+  }
+
  [[nodiscard]] bool IsValidImpl(TrainParam const& param, bst_node_t num_leaves) const {
    if (split.loss_chg <= kRtEps) return false;
    if (split.left_sum.GetHess() == 0 || split.right_sum.GetHess() == 0) {
@@ -88,6 +170,32 @@ struct MultiExpandEntry : public ExpandEntryImpl<MultiExpandEntry> {
  MultiExpandEntry() = default;
  MultiExpandEntry(bst_node_t nidx, bst_node_t depth) : ExpandEntryImpl{nidx, depth} {}

+  void SaveGrad(Json* p_out) const {
+    auto& out = *p_out;
+    auto save = [&](std::string const& name, std::vector<GradientPairPrecise> const& sum) {
+      out[name] = F32Array{sum.size() * 2};
+      auto& array = get<F32Array>(out[name]);
+      for (std::size_t i = 0, j = 0; i < sum.size(); i++, j += 2) {
+        array[j] = sum[i].GetGrad();
+        array[j + 1] = sum[i].GetHess();
+      }
+    };
+    save("left_sum", this->split.left_sum);
+    save("right_sum", this->split.right_sum);
+  }
+  void LoadGrad(Json const& in) {
+    auto load = [&](std::string const& name, std::vector<GradientPairPrecise>* p_sum) {
+      auto const& array = get<F32Array const>(in[name]);
+      auto& sum = *p_sum;
+      sum.resize(array.size() / 2);
+      for (std::size_t i = 0, j = 0; i < sum.size(); ++i, j += 2) {
+        sum[i] = GradientPairPrecise{array[j], array[j + 1]};
+      }
+    };
+    load("left_sum", &this->split.left_sum);
+    load("right_sum", &this->split.right_sum);
+  }
+
  [[nodiscard]] bool IsValidImpl(TrainParam const& param, bst_node_t num_leaves) const {
    if (split.loss_chg <= kRtEps) return false;
    auto is_zero = [](auto const& sum) {
--- a/src/tree/param.h
+++ b/src/tree/param.h
@@ -401,7 +401,7 @@ struct SplitEntryContainer {
  /*! \brief split index */
  bst_feature_t sindex{0};
  bst_float split_value{0.0f};
-  std::vector<uint32_t> cat_bits;
+  std::vector<std::uint32_t> cat_bits;
  bool is_cat{false};

  GradientT left_sum;
--- a/src/tree/updater_gpu_common.cuh
+++ b/src/tree/updater_gpu_common.cuh
@@ -14,9 +14,7 @@
 #include "gpu_hist/histogram.cuh"
 #include "param.h"

-namespace xgboost {
-namespace tree {
-
+namespace xgboost::tree {
 struct GPUTrainingParam {
  // minimum amount of hessian(weight) allowed in a child
  float min_child_weight;
@@ -136,5 +134,4 @@ struct SumCallbackOp {
    return old_prefix;
  }
 };
-}  // namespace tree
-}  // namespace xgboost
+}  // namespace xgboost::tree