1 files changed, 37 insertions, 0 deletions
diff --git a/searchlib/src/tests/common/bitvector/bitvector_benchmark.cpp b/searchlib/src/tests/common/bitvector/bitvector_benchmark.cpp
new file mode 100644
index 00000000000..cc0ef78c193
--- /dev/null
+++ b/searchlib/src/tests/common/bitvector/bitvector_benchmark.cpp
@@ -0,0 +1,37 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#include <vespa/fastos/fastos.h>
+#include <vespa/log/log.h>
+LOG_SETUP("bitvector_benchmark");
+#include <vespa/vespalib/testkit/testapp.h>
+#include <vespa/searchlib/common/bitvector.h>
+
+using namespace search;
+
+namespace {
+
+size_t scan(BitVector & bv) __attribute__((noinline));
+
+size_t scan(BitVector & bv)
+{
+    size_t count(0);
+    for (BitVector::Index i(bv.getFirstTrueBit()), m(bv.size()); i < m; i = bv.getNextTrueBit(i+1)) {
+        count++;
+    }
+    return count;
+}
+
+}
+
+// This test is 10% faster with table lookup than with runtime shifting.
+TEST("speed of getNextTrueBit")
+{
+    BitVector::UP bv(BitVector::create(100000000));
+    bv->setInterval(0, bv->size() - 1);
+
+    for (size_t i(0); i < 10; i++) {
+        EXPECT_EQUAL(bv->size(), scan(*bv));
+    }
+    EXPECT_EQUAL(bv->size(), bv->countTrueBits());
+}
+
+TEST_MAIN() { TEST_RUN_ALL(); }