Add a benchmark for QSharedPointer

Initial results with GCC:

Even though GCC's assembly looks rather bad because of the implicit
fall-back from atomics to non-atomics for single-threaded
applications, libstdc++'s shared_ptr still performs twice as fast as
QSharedPointer, proving that the branch predictor eats libstdc++'s
is-multi-threaded-check for breakfast and the two atomic operations of
a QSharedPointer copy vs. one for std::shared_ptr dominate the
run-time.

********* Start testing of tst_QSharedPointer *********
Config: Using QtTest library 6.2.0, Qt 6.2.0 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 11.1.1 20210712), ubuntu 20.04
PASS   : tst_QSharedPointer::initTestCase()
PASS   : tst_QSharedPointer::refAndDeref_null_QSP_int()
RESULT : tst_QSharedPointer::refAndDeref_null_QSP_int():
     0.0000024 msecs per iteration (total: 81, iterations: 33554432)
PASS   : tst_QSharedPointer::refAndDeref_null_SSP_int()
RESULT : tst_QSharedPointer::refAndDeref_null_SSP_int():
     0.0000024 msecs per iteration (total: 81, iterations: 33554432)
PASS   : tst_QSharedPointer::refAndDeref_null_BSP_int()
RESULT : tst_QSharedPointer::refAndDeref_null_BSP_int():
     0.0000025 msecs per iteration (total: 87, iterations: 33554432)
PASS   : tst_QSharedPointer::refAndDeref_null_QSP_QString()
RESULT : tst_QSharedPointer::refAndDeref_null_QSP_QString():
     0.0000025 msecs per iteration (total: 86, iterations: 33554432)
PASS   : tst_QSharedPointer::refAndDeref_null_SSP_QString()
RESULT : tst_QSharedPointer::refAndDeref_null_SSP_QString():
     0.0000023 msecs per iteration (total: 80, iterations: 33554432)
PASS   : tst_QSharedPointer::refAndDeref_null_BSP_QString()
RESULT : tst_QSharedPointer::refAndDeref_null_BSP_QString():
     0.0000026 msecs per iteration (total: 88, iterations: 33554432)
PASS   : tst_QSharedPointer::refAndDeref_nonnull_QSP_int()
RESULT : tst_QSharedPointer::refAndDeref_nonnull_QSP_int():
     0.000019 msecs per iteration (total: 83, iterations: 4194304)
PASS   : tst_QSharedPointer::refAndDeref_nonnull_SSP_int()
RESULT : tst_QSharedPointer::refAndDeref_nonnull_SSP_int():
     0.000010 msecs per iteration (total: 90, iterations: 8388608)
PASS   : tst_QSharedPointer::refAndDeref_nonnull_BSP_int()
RESULT : tst_QSharedPointer::refAndDeref_nonnull_BSP_int():
     0.0000094 msecs per iteration (total: 79, iterations: 8388608)
PASS   : tst_QSharedPointer::refAndDeref_nonnull_QSP_QString()
RESULT : tst_QSharedPointer::refAndDeref_nonnull_QSP_QString():
     0.000017 msecs per iteration (total: 75, iterations: 4194304)
PASS   : tst_QSharedPointer::refAndDeref_nonnull_SSP_QString()
RESULT : tst_QSharedPointer::refAndDeref_nonnull_SSP_QString():
     0.000010 msecs per iteration (total: 90, iterations: 8388608)
PASS   : tst_QSharedPointer::refAndDeref_nonnull_BSP_QString()
RESULT : tst_QSharedPointer::refAndDeref_nonnull_BSP_QString():
     0.0000091 msecs per iteration (total: 77, iterations: 8388608)
PASS   : tst_QSharedPointer::threadedRefAndDeref_null_QSP_int()
RESULT : tst_QSharedPointer::threadedRefAndDeref_null_QSP_int():
     0.000016 msecs per iteration (total: 68, iterations: 4194304)
PASS   : tst_QSharedPointer::threadedRefAndDeref_null_SSP_int()
RESULT : tst_QSharedPointer::threadedRefAndDeref_null_SSP_int():
     0.000025 msecs per iteration (total: 53, iterations: 2097152)
PASS   : tst_QSharedPointer::threadedRefAndDeref_null_BSP_int()
RESULT : tst_QSharedPointer::threadedRefAndDeref_null_BSP_int():
     0.000027 msecs per iteration (total: 58, iterations: 2097152)
PASS   : tst_QSharedPointer::threadedRefAndDeref_null_QSP_QString()
RESULT : tst_QSharedPointer::threadedRefAndDeref_null_QSP_QString():
     0.000016 msecs per iteration (total: 71, iterations: 4194304)
PASS   : tst_QSharedPointer::threadedRefAndDeref_null_SSP_QString()
RESULT : tst_QSharedPointer::threadedRefAndDeref_null_SSP_QString():
     0.000027 msecs per iteration (total: 58, iterations: 2097152)
PASS   : tst_QSharedPointer::threadedRefAndDeref_null_BSP_QString()
RESULT : tst_QSharedPointer::threadedRefAndDeref_null_BSP_QString():
     0.000017 msecs per iteration (total: 73, iterations: 4194304)
PASS   : tst_QSharedPointer::threadedRefAndDeref_nonnull_QSP_int()
RESULT : tst_QSharedPointer::threadedRefAndDeref_nonnull_QSP_int():
     0.00073 msecs per iteration (total: 96, iterations: 131072)
PASS   : tst_QSharedPointer::threadedRefAndDeref_nonnull_SSP_int()
RESULT : tst_QSharedPointer::threadedRefAndDeref_nonnull_SSP_int():
     0.000408 msecs per iteration (total: 107, iterations: 262144)
PASS   : tst_QSharedPointer::threadedRefAndDeref_nonnull_BSP_int()
RESULT : tst_QSharedPointer::threadedRefAndDeref_nonnull_BSP_int():
     0.00033 msecs per iteration (total: 89, iterations: 262144)
PASS   : tst_QSharedPointer::threadedRefAndDeref_nonnull_QSP_QString()
RESULT : tst_QSharedPointer::threadedRefAndDeref_nonnull_QSP_QString():
     0.000877 msecs per iteration (total: 115, iterations: 131072)
PASS   : tst_QSharedPointer::threadedRefAndDeref_nonnull_SSP_QString()
RESULT : tst_QSharedPointer::threadedRefAndDeref_nonnull_SSP_QString():
     0.00033 msecs per iteration (total: 89, iterations: 262144)
PASS   : tst_QSharedPointer::threadedRefAndDeref_nonnull_BSP_QString()
RESULT : tst_QSharedPointer::threadedRefAndDeref_nonnull_BSP_QString():
     0.000385 msecs per iteration (total: 101, iterations: 262144)
PASS   : tst_QSharedPointer::cleanupTestCase()
Totals: 26 passed, 0 failed, 0 skipped, 0 blacklisted, 7995ms
********* Finished testing of tst_QSharedPointer *********

Change-Id: I0bed70142ffdbde6898ec0e27cb470b50fc0e97d
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/tests/benchmarks/corelib/tools/qsharedpointer/CMakeLists.txt b/tests/benchmarks/corelib/tools/qsharedpointer/CMakeLists.txt
new file mode 100644
index 0000000000..5103fc3229
--- /dev/null
+++ b/tests/benchmarks/corelib/tools/qsharedpointer/CMakeLists.txt
@@ -0,0 +1,9 @@
+qt_internal_add_benchmark(tst_bench_shared_ptr
+    SOURCES
+        tst_bench_shared_ptr.cpp
+    INCLUDE_DIRECTORIES
+        .
+    PUBLIC_LIBRARIES
+        Qt::Core
+        Qt::Test
+)