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author | Marc Mutz <marc.mutz@kdab.com> | 2019-12-18 15:43:24 +0100 |
---|---|---|
committer | Marc Mutz <marc.mutz@kdab.com> | 2020-01-26 08:11:58 +0000 |
commit | f21a6d409ea0504c64cd72861fc16b6f3e080086 (patch) | |
tree | cdc7561bd0db6df74bf36d65a9ea73a5315a2ec3 /tests/benchmarks/corelib/text/qstringlist | |
parent | bf330a8f034a8d6198a78f87d23eafc5ef7e6ffb (diff) |
QStringList: use local storage in removeDuplicates()
If available, use a C++17 std::pmr::unordered_set with a monotonic
buffer resource and a 256-byte stack buffer to avoid the per-element
allocations of QSet.
Results on my machine:
RESULT : tst_QStringList::removeDuplicates():"empty":
- 0.00014 msecs per iteration (total: 74, iterations: 524288)
+ 0.000031 msecs per iteration (total: 66, iterations: 2097152)
RESULT : tst_QStringList::removeDuplicates():"short-dup-0.00":
- 0.00043 msecs per iteration (total: 57, iterations: 131072)
+ 0.00013 msecs per iteration (total: 69, iterations: 524288)
RESULT : tst_QStringList::removeDuplicates():"short-dup-0.50":
- 0.00049 msecs per iteration (total: 65, iterations: 131072)
+ 0.00032 msecs per iteration (total: 85, iterations: 262144)
RESULT : tst_QStringList::removeDuplicates():"short-dup-0.66":
- 0.00057 msecs per iteration (total: 75, iterations: 131072)
+ 0.00039 msecs per iteration (total: 52, iterations: 131072)
RESULT : tst_QStringList::removeDuplicates():"short-dup-0.75":
- 0.00064 msecs per iteration (total: 85, iterations: 131072)
+ 0.00048 msecs per iteration (total: 63, iterations: 131072)
RESULT : tst_QStringList::removeDuplicates():"long-dup-0.00":
- 0.083 msecs per iteration (total: 85, iterations: 1024)
+ 0.039 msecs per iteration (total: 80, iterations: 2048)
RESULT : tst_QStringList::removeDuplicates():"long-dup-0.50":
- 0.11 msecs per iteration (total: 58, iterations: 512)
+ 0.078 msecs per iteration (total: 80, iterations: 1024)
RESULT : tst_QStringList::removeDuplicates():"long-dup-0.66":
- 0.13 msecs per iteration (total: 70, iterations: 512)
+ 0.10 msecs per iteration (total: 53, iterations: 512)
RESULT : tst_QStringList::removeDuplicates():"long-dup-0.75":
- 0.16 msecs per iteration (total: 86, iterations: 512)
+ 0.13 msecs per iteration (total: 69, iterations: 512)
When interpreting the data, take into account that each iteration
contains _also_ a deep copy of the QStringList d/t the detach from
'input'.
The pattern is used elsewhere in Qt, so I've put the class that
implements the seen set into a private header file and used in some
other places I found.
Change-Id: I1f71a82008a16d5a3818f91f290ade21d837805e
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Diffstat (limited to 'tests/benchmarks/corelib/text/qstringlist')
-rw-r--r-- | tests/benchmarks/corelib/text/qstringlist/main.cpp | 39 | ||||
-rw-r--r-- | tests/benchmarks/corelib/text/qstringlist/qstringlist.pro | 1 |
2 files changed, 40 insertions, 0 deletions
diff --git a/tests/benchmarks/corelib/text/qstringlist/main.cpp b/tests/benchmarks/corelib/text/qstringlist/main.cpp index ae355a8b89..9f184d0cf5 100644 --- a/tests/benchmarks/corelib/text/qstringlist/main.cpp +++ b/tests/benchmarks/corelib/text/qstringlist/main.cpp @@ -41,6 +41,9 @@ private slots: void join() const; void join_data() const; + void removeDuplicates() const; + void removeDuplicates_data() const; + void split_qlist_qbytearray() const; void split_qlist_qbytearray_data() const { return split_data(); } @@ -116,6 +119,42 @@ void tst_QStringList::join_data() const << QString(); } +void tst_QStringList::removeDuplicates() const +{ + QFETCH(const QStringList, input); + + QBENCHMARK { + auto copy = input; + copy.removeDuplicates(); + } +} + +void tst_QStringList::removeDuplicates_data() const +{ + QTest::addColumn<QStringList>("input"); + + const QStringList s = {"one", "two", "three"}; + + QTest::addRow("empty") << QStringList(); + QTest::addRow("short-dup-0.00") << s; + QTest::addRow("short-dup-0.50") << (s + s); + QTest::addRow("short-dup-0.66") << (s + s + s); + QTest::addRow("short-dup-0.75") << (s + s + s + s); + + const QStringList l = []() { + QStringList result; + const int n = 1000; + result.reserve(n); + for (int i = 0; i < n; ++i) + result.push_back(QString::number(i)); + return result; + }(); + QTest::addRow("long-dup-0.00") << l; + QTest::addRow("long-dup-0.50") << (l + l); + QTest::addRow("long-dup-0.66") << (l + l + l); + QTest::addRow("long-dup-0.75") << (l + l + l + l); +} + void tst_QStringList::split_data() const { QTest::addColumn<QString>("input"); diff --git a/tests/benchmarks/corelib/text/qstringlist/qstringlist.pro b/tests/benchmarks/corelib/text/qstringlist/qstringlist.pro index 5803e7da0e..2e7ae058f7 100644 --- a/tests/benchmarks/corelib/text/qstringlist/qstringlist.pro +++ b/tests/benchmarks/corelib/text/qstringlist/qstringlist.pro @@ -1,5 +1,6 @@ TARGET = tst_bench_qstringlist CONFIG -= debug CONFIG += release +CONFIG += benchmark QT = core testlib SOURCES += main.cpp |