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Avoid regenerating the gradient index for approx. (#7591)

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This commit is contained in:
Jiaming Yuan
2022-01-26 21:41:30 +08:00
committed by GitHub
parent 5d7818e75d
commit e060519d4f
7 changed files with 40 additions and 18 deletions
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1
src/tree/hist/evaluate_splits.h
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@@ -351,6 +351,7 @@ template <typename GradientSumT, typename ExpandEntry> class HistEvaluator {
auto Evaluator() const { return tree_evaluator_.GetEvaluator(); }
auto const& Stats() const { return snode_; }
auto Task() const { return task_; }
float InitRoot(GradStats const& root_sum) {
snode_.resize(1);

32
src/tree/updater_approx.cc
View File

@@ -26,6 +26,19 @@ namespace tree {
DMLC_REGISTRY_FILE_TAG(updater_approx);
namespace {
// Return the BatchParam used by DMatrix.
template <typename GradientSumT>
auto BatchSpec(TrainParam const &p, common::Span<float> hess,
HistEvaluator<GradientSumT, CPUExpandEntry> const &evaluator) {
return BatchParam{GenericParameter::kCpuId, p.max_bin, hess, !evaluator.Task().const_hess};
}
auto BatchSpec(TrainParam const &p, common::Span<float> hess) {
return BatchParam{GenericParameter::kCpuId, p.max_bin, hess, false};
}
} // anonymous namespace
template <typename GradientSumT>
class GloablApproxBuilder {
protected:
@@ -46,12 +59,13 @@ class GloablApproxBuilder {
public:
void InitData(DMatrix *p_fmat, common::Span<float> hess) {
monitor_->Start(__func__);
n_batches_ = 0;
int32_t n_total_bins = 0;
partitioner_.clear();
// Generating the GHistIndexMatrix is quite slow, is there a way to speed it up?
for (auto const &page : p_fmat->GetBatches<GHistIndexMatrix>(
{GenericParameter::kCpuId, param_.max_bin, hess, true})) {
for (auto const &page :
p_fmat->GetBatches<GHistIndexMatrix>(BatchSpec(param_, hess, evaluator_))) {
if (n_total_bins == 0) {
n_total_bins = page.cut.TotalBins();
feature_values_ = page.cut;
@@ -62,9 +76,8 @@ class GloablApproxBuilder {
n_batches_++;
}
histogram_builder_.Reset(n_total_bins,
BatchParam{GenericParameter::kCpuId, param_.max_bin, hess},
ctx_->Threads(), n_batches_, rabit::IsDistributed());
histogram_builder_.Reset(n_total_bins, BatchSpec(param_, hess), ctx_->Threads(), n_batches_,
rabit::IsDistributed());
monitor_->Stop(__func__);
}
@@ -82,8 +95,7 @@ class GloablApproxBuilder {
std::vector<CPUExpandEntry> nodes{best};
size_t i = 0;
auto space = this->ConstructHistSpace(nodes);
for (auto const &page :
p_fmat->GetBatches<GHistIndexMatrix>({GenericParameter::kCpuId, param_.max_bin, hess})) {
for (auto const &page : p_fmat->GetBatches<GHistIndexMatrix>(BatchSpec(param_, hess))) {
histogram_builder_.BuildHist(i, space, page, p_tree, partitioner_.at(i).Partitions(), nodes,
{}, gpair);
i++;
@@ -175,8 +187,7 @@ class GloablApproxBuilder {
size_t i = 0;
auto space = this->ConstructHistSpace(nodes_to_build);
for (auto const &page :
p_fmat->GetBatches<GHistIndexMatrix>({GenericParameter::kCpuId, param_.max_bin, hess})) {
for (auto const &page : p_fmat->GetBatches<GHistIndexMatrix>(BatchSpec(param_, hess))) {
histogram_builder_.BuildHist(i, space, page, p_tree, partitioner_.at(i).Partitions(),
nodes_to_build, nodes_to_sub, gpair);
i++;
@@ -225,8 +236,7 @@ class GloablApproxBuilder {
monitor_->Start("UpdatePosition");
size_t i = 0;
for (auto const &page :
p_fmat->GetBatches<GHistIndexMatrix>({GenericParameter::kCpuId, param_.max_bin, hess})) {
for (auto const &page : p_fmat->GetBatches<GHistIndexMatrix>(BatchSpec(param_, hess))) {
partitioner_.at(i).UpdatePosition(ctx_, page, applied, p_tree);
i++;
}