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Initial GPU support for the approx tree method. (#9414)

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This commit is contained in:
Jiaming Yuan
2023-07-31 15:50:28 +08:00
committed by GitHub
parent 8f0efb4ab3
commit 912e341d57
23 changed files with 639 additions and 360 deletions
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28
src/tree/gpu_hist/gradient_based_sampler.cu
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@@ -8,10 +8,10 @@
#include <xgboost/logging.h>
#include <algorithm>
#include <cstddef> // for size_t
#include <limits>
#include <utility>
#include "../../common/compressed_iterator.h"
#include "../../common/cuda_context.cuh" // for CUDAContext
#include "../../common/random.h"
#include "../param.h"
@@ -202,27 +202,27 @@ ExternalMemoryUniformSampling::ExternalMemoryUniformSampling(size_t n_rows,
GradientBasedSample ExternalMemoryUniformSampling::Sample(Context const* ctx,
common::Span<GradientPair> gpair,
DMatrix* dmat) {
auto cuctx = ctx->CUDACtx();
// Set gradient pair to 0 with p = 1 - subsample
thrust::replace_if(dh::tbegin(gpair), dh::tend(gpair),
thrust::counting_iterator<size_t>(0),
BernoulliTrial(common::GlobalRandom()(), subsample_),
GradientPair());
thrust::replace_if(cuctx->CTP(), dh::tbegin(gpair), dh::tend(gpair),
thrust::counting_iterator<std::size_t>(0),
BernoulliTrial(common::GlobalRandom()(), subsample_), GradientPair{});
// Count the sampled rows.
size_t sample_rows = thrust::count_if(dh::tbegin(gpair), dh::tend(gpair), IsNonZero());
size_t sample_rows =
thrust::count_if(cuctx->CTP(), dh::tbegin(gpair), dh::tend(gpair), IsNonZero{});
// Compact gradient pairs.
gpair_.resize(sample_rows);
thrust::copy_if(dh::tbegin(gpair), dh::tend(gpair), gpair_.begin(), IsNonZero());
thrust::copy_if(cuctx->CTP(), dh::tbegin(gpair), dh::tend(gpair), gpair_.begin(), IsNonZero{});
// Index the sample rows.
thrust::transform(dh::tbegin(gpair), dh::tend(gpair), sample_row_index_.begin(), IsNonZero());
thrust::exclusive_scan(sample_row_index_.begin(), sample_row_index_.end(),
thrust::transform(cuctx->CTP(), dh::tbegin(gpair), dh::tend(gpair), sample_row_index_.begin(),
IsNonZero());
thrust::exclusive_scan(cuctx->CTP(), sample_row_index_.begin(), sample_row_index_.end(),
sample_row_index_.begin());
thrust::transform(dh::tbegin(gpair), dh::tend(gpair),
sample_row_index_.begin(),
sample_row_index_.begin(),
ClearEmptyRows());
thrust::transform(cuctx->CTP(), dh::tbegin(gpair), dh::tend(gpair), sample_row_index_.begin(),
sample_row_index_.begin(), ClearEmptyRows());
auto batch_iterator = dmat->GetBatches<EllpackPage>(ctx, batch_param_);
auto first_page = (*batch_iterator.begin()).Impl();
@@ -232,7 +232,7 @@ GradientBasedSample ExternalMemoryUniformSampling::Sample(Context const* ctx,
first_page->row_stride, sample_rows));
// Compact the ELLPACK pages into the single sample page.
thrust::fill(dh::tbegin(page_->gidx_buffer), dh::tend(page_->gidx_buffer), 0);
thrust::fill(cuctx->CTP(), dh::tbegin(page_->gidx_buffer), dh::tend(page_->gidx_buffer), 0);
for (auto& batch : batch_iterator) {
page_->Compact(ctx->gpu_id, batch.Impl(), dh::ToSpan(sample_row_index_));
}