[llvm-exegesis] InstructionBenchmarkClustering::rangeQuery(): use llvm::SmallVector<size_t, 0> for storage.
Summary:
Old: (D54383)
```
Performance counter stats for './bin/llvm-exegesis -mode=analysis -analysis-epsilon=100000 -benchmarks-file=/tmp/benchmarks.yaml -analysis-inconsistencies-output-file=/tmp/clusters.html' (10 runs):
9098.781978 task-clock (msec) # 1.000 CPUs utilized ( +- 0.16% )
...
9.1015 +- 0.0148 seconds time elapsed ( +- 0.16% )
```
New:
```
Performance counter stats for './bin/llvm-exegesis -mode=analysis -analysis-epsilon=100000 -benchmarks-file=/tmp/benchmarks.yaml -analysis-inconsistencies-output-file=/tmp/clusters.html' (10 runs):
8553.352480 task-clock (msec) # 1.000 CPUs utilized ( +- 0.12% )
...
8.5539 +- 0.0105 seconds time elapsed ( +- 0.12% )
```
So another -6%.
That is because the `SmallVector` **doubles** it size when reallocating, which is great here,
since we can't `reserve()` since we can't know how many `Neighbors` we will have.
Reviewers: courbet, MaskRay, RKSimon, gchatelet, john.brawn
Subscribers: tschuett, llvm-commits
Differential Revision: https://reviews.llvm.org/D54388
llvm-svn: 347200
diff --git a/llvm/tools/llvm-exegesis/lib/Clustering.cpp b/llvm/tools/llvm-exegesis/lib/Clustering.cpp
index f61bfbc..9ff4c02 100644
--- a/llvm/tools/llvm-exegesis/lib/Clustering.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Clustering.cpp
@@ -9,6 +9,7 @@
#include "Clustering.h"
#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallVector.h"
#include <string>
namespace llvm {
@@ -32,9 +33,9 @@
// Finds the points at distance less than sqrt(EpsilonSquared) of Q (not
// including Q).
-std::vector<size_t>
+llvm::SmallVector<size_t, 0>
InstructionBenchmarkClustering::rangeQuery(const size_t Q) const {
- std::vector<size_t> Neighbors;
+ llvm::SmallVector<size_t, 0> Neighbors;
const auto &QMeasurements = Points_[Q].Measurements;
for (size_t P = 0, NumPoints = Points_.size(); P < NumPoints; ++P) {
if (P == Q)
diff --git a/llvm/tools/llvm-exegesis/lib/Clustering.h b/llvm/tools/llvm-exegesis/lib/Clustering.h
index 9dc0adf..0d8a463 100644
--- a/llvm/tools/llvm-exegesis/lib/Clustering.h
+++ b/llvm/tools/llvm-exegesis/lib/Clustering.h
@@ -97,7 +97,7 @@
const std::vector<InstructionBenchmark> &Points, double EpsilonSquared);
llvm::Error validateAndSetup();
void dbScan(size_t MinPts);
- std::vector<size_t> rangeQuery(size_t Q) const;
+ llvm::SmallVector<size_t, 0> rangeQuery(size_t Q) const;
const std::vector<InstructionBenchmark> &Points_;
const double EpsilonSquared_;