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Combine thread launches into single launch per tree for gpu_hist (#4343)

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* Combine thread launches into single launch per tree for gpu_hist
algorithm.

* Address deprecation warning

* Add manual column sampler constructor

* Turn off omp dynamic to get a guaranteed number of threads

* Enable openmp in cuda code
This commit is contained in:
Rory Mitchell
2019-04-29 09:58:34 +12:00
committed by GitHub
parent 146e83f3b3
commit 5e582b0fa7
10 changed files with 402 additions and 325 deletions
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31
tests/cpp/common/test_random.cc
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@@ -1,3 +1,4 @@
#include <valarray>
#include "../../../src/common/random.h"
#include "../helpers.h"
#include "gtest/gtest.h"
@@ -33,7 +34,8 @@ TEST(ColumnSampler, Test) {
// No level or node sampling, should be the same at different depth
cs.Init(n, 1.0f, 1.0f, 0.5f);
ASSERT_EQ(cs.GetFeatureSet(0)->HostVector(), cs.GetFeatureSet(1)->HostVector());
ASSERT_EQ(cs.GetFeatureSet(0)->HostVector(),
cs.GetFeatureSet(1)->HostVector());
cs.Init(n, 1.0f, 1.0f, 1.0f);
auto set5 = *cs.GetFeatureSet(0);
@@ -45,7 +47,34 @@ TEST(ColumnSampler, Test) {
// Should always be a minimum of one feature
cs.Init(n, 1e-16f, 1e-16f, 1e-16f);
ASSERT_EQ(cs.GetFeatureSet(0)->Size(), 1);
}
// Test if different threads using the same seed produce the same result
TEST(ColumnSampler, ThreadSynchronisation) {
const int64_t num_threads = 100;
int n = 128;
int iterations = 10;
int levels = 5;
std::vector<int> reference_result;
bool success =
true; // Cannot use google test asserts in multithreaded region
#pragma omp parallel num_threads(num_threads)
{
for (auto j = 0ull; j < iterations; j++) {
ColumnSampler cs(j);
cs.Init(n, 0.5f, 0.5f, 0.5f);
for (auto level = 0ull; level < levels; level++) {
auto result = cs.GetFeatureSet(level)->ConstHostVector();
#pragma omp single
{ reference_result = result; }
if (result != reference_result) {
success = false;
}
#pragma omp barrier
}
}
}
ASSERT_TRUE(success);
}
} // namespace common
} // namespace xgboost