Implement parallel version of super-scalar-sample-sort...

and use it for the pivot table construction routine processBuckets().

The implementation uses ideas from the non-parallel sample sort discussed in the below paper,
but parallelizes the "binning"/"classification" operations and the sorting of the bins
themselves.

Sanders, Peter, and Sebastian Winkel. "Super scalar sample sort."
European Symposium on Algorithms. Springer, Berlin, Heidelberg, 2004.

which can be accessed at :
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.72.366&rep=rep1&type=pdf

Change-Id: I3723b87e2feb8d7d9ee03f71f6025e26add914ce
Reviewed-on: https://gerrit.libreoffice.org/79486
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

3 files changed, 132 insertions, 0 deletions

diff --git a/comphelper/CppunitTest_comphelper_parallelsort_test.mk b/comphelper/CppunitTest_comphelper_parallelsort_test.mk
new file mode 100644
index 000000000000..e1d2eab9ec36
--- /dev/null
+++ b/comphelper/CppunitTest_comphelper_parallelsort_test.mk
@@ -0,0 +1,30 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+
+$(eval $(call gb_CppunitTest_CppunitTest,comphelper_parallelsort_test))
+
+$(eval $(call gb_CppunitTest_add_exception_objects,comphelper_parallelsort_test, \
+    comphelper/qa/unit/parallelsorttest \
+))
+
+$(eval $(call gb_CppunitTest_use_externals,comphelper_parallelsort_test,\
+	boost_headers \
+))
+
+$(eval $(call gb_CppunitTest_use_sdk_api,comphelper_parallelsort_test))
+
+$(eval $(call gb_CppunitTest_use_libraries,comphelper_parallelsort_test, \
+    comphelper \
+    cppuhelper \
+    cppu \
+    sal \
+    tl \
+))
+
+# vim: set noet sw=4 ts=4:
\ No newline at end of file
diff --git a/comphelper/Module_comphelper.mk b/comphelper/Module_comphelper.mk
index 30ac708a927d..7541a59f1641 100644
--- a/comphelper/Module_comphelper.mk
+++ b/comphelper/Module_comphelper.mk
@@ -30,6 +30,7 @@ $(eval $(call gb_Module_add_subsequentcheck_targets,comphelper,\
 ))
 
 $(eval $(call gb_Module_add_check_targets,comphelper,\
+    CppunitTest_comphelper_parallelsort_test \
     CppunitTest_comphelper_threadpool_test \
     CppunitTest_comphelper_syntaxhighlight_test \
     CppunitTest_comphelper_variadictemplates_test \
diff --git a/comphelper/qa/unit/parallelsorttest.cxx b/comphelper/qa/unit/parallelsorttest.cxx
new file mode 100644
index 000000000000..90dcb3c235ba
--- /dev/null
+++ b/comphelper/qa/unit/parallelsorttest.cxx
@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <comphelper/parallelsort.hxx>
+#include <comphelper/threadpool.hxx>
+#include <rtl/string.hxx>
+#include <cppunit/TestAssert.h>
+#include <cppunit/TestFixture.h>
+#include <cppunit/extensions/HelperMacros.h>
+#include <cppunit/plugin/TestPlugIn.h>
+
+#include <cstdlib>
+#include <vector>
+#include <algorithm>
+#include <random>
+
+class ParallelSortTest : public CppUnit::TestFixture
+{
+public:
+    void testSortTiny();
+    void testSortMedium();
+    void testSortBig();
+
+    virtual void setUp() override;
+    virtual void tearDown() override;
+
+    CPPUNIT_TEST_SUITE(ParallelSortTest);
+    CPPUNIT_TEST(testSortTiny);
+    CPPUNIT_TEST(testSortMedium);
+    CPPUNIT_TEST(testSortBig);
+    CPPUNIT_TEST_SUITE_END();
+
+private:
+    void sortTest(size_t nLen);
+    void fillRandomUptoN(std::vector<size_t>& rVector, size_t N);
+
+    comphelper::ThreadPool* pThreadPool;
+    size_t mnThreads;
+};
+
+void ParallelSortTest::setUp()
+{
+    pThreadPool = &comphelper::ThreadPool::getSharedOptimalPool();
+    mnThreads = pThreadPool->getWorkerCount();
+}
+
+void ParallelSortTest::tearDown()
+{
+    if (pThreadPool)
+        pThreadPool->joinAll();
+}
+
+void ParallelSortTest::fillRandomUptoN(std::vector<size_t>& rVector, size_t N)
+{
+    rVector.resize(N);
+    for (size_t nIdx = 0; nIdx < N; ++nIdx)
+        rVector[nIdx] = nIdx;
+    std::shuffle(rVector.begin(), rVector.end(), std::default_random_engine(42));
+}
+
+void ParallelSortTest::sortTest(size_t nLen)
+{
+    std::vector<size_t> aVector(nLen);
+    fillRandomUptoN(aVector, nLen);
+    comphelper::parallelSort(aVector.begin(), aVector.end());
+    for (size_t nIdx = 0; nIdx < nLen; ++nIdx)
+    {
+        OString aMsg = "Wrong aVector[" + OString::number(nIdx) + "]";
+        CPPUNIT_ASSERT_EQUAL_MESSAGE(aMsg.getStr(), nIdx, aVector[nIdx]);
+    }
+}
+
+void ParallelSortTest::testSortTiny()
+{
+    sortTest(5);
+    sortTest(15);
+    sortTest(16);
+    sortTest(17);
+}
+
+void ParallelSortTest::testSortMedium()
+{
+    sortTest(1025);
+    sortTest(1029);
+    sortTest(1024 * 2 + 1);
+    sortTest(1024 * 2 + 9);
+}
+
+void ParallelSortTest::testSortBig() { sortTest(1024 * 16 + 3); }
+
+CPPUNIT_TEST_SUITE_REGISTRATION(ParallelSortTest);
+
+CPPUNIT_PLUGIN_IMPLEMENT();
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */