From a8ae8e3130fe4953ebfd54bce15648f58cd3f5be Mon Sep 17 00:00:00 2001 From: David Faure Date: Fri, 3 Mar 2017 14:06:49 +0100 Subject: QDateTime::fromString(): improve performance by 33% getMaximum() and getMinimum(), called during parsing, create new QDateTime instances, which on Linux end up calling mktime(). Making these static (for the common case of LocalTime spec) improves performance dramatically, when parsing several date/times. tests/benchmarks/corelib/tools/qdatetime/ (after fixing it to actually parse a valid date/time) says: RESULT : tst_QDateTime::fromString(): - 36,742,060 instruction reads per iteration (total: 36,742,060, iterations: 1) + 24,230,060 instruction reads per iteration (total: 24,230,060, iterations: 1) Change-Id: I0c3931285475bf19a5be8cba1486ed07cbf5e134 Reviewed-by: Thiago Macieira --- tests/benchmarks/corelib/tools/qdatetime/main.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'tests/benchmarks') diff --git a/tests/benchmarks/corelib/tools/qdatetime/main.cpp b/tests/benchmarks/corelib/tools/qdatetime/main.cpp index 8f43a412b7..2c1e3d97ae 100644 --- a/tests/benchmarks/corelib/tools/qdatetime/main.cpp +++ b/tests/benchmarks/corelib/tools/qdatetime/main.cpp @@ -547,8 +547,9 @@ void tst_QDateTime::currentMSecsSinceEpoch() void tst_QDateTime::fromString() { - QString format = "yyy-MM-dd hh:mm:ss.zzz t"; - QString input = "2010-01-01 13:12:11.999 UTC"; + QString format = "yyyy-MM-dd hh:mm:ss.zzz"; + QString input = "2010-01-01 13:12:11.999"; + QVERIFY(QDateTime::fromString(input, format).isValid()); QBENCHMARK { for (int i = 0; i < 1000; ++i) QDateTime::fromString(input, format); -- cgit v1.2.3