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Loop test time work in progress.

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This commit is contained in:
Beman
2013-05-28 07:37:52 -04:00
parent 50b5488997
commit a55a44c67b
4 changed files with 121 additions and 67 deletions
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4
build/Jamfile.v2
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@ -12,9 +12,11 @@ project
SOURCES = speed_test speed_test_functions ;
exe "speed_test"
: $(SOURCES).cpp ../../timer/build//boost_timer
: $(SOURCES).cpp ../../timer/build//boost_timer
: <toolset>gcc:<cxxflags>-march=native
;
exe "loop_time_test"
: loop_time_test.cpp ../../timer/build//boost_timer
: <toolset>gcc:<cxxflags>-march=native
;

29
doc/index.html
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@ -224,15 +224,16 @@ big_endian(x);
</tr>
</table>
<p>There will be no performance difference between the two approaches. Optimizing compilers will likely
<p><b>There will be no performance difference between the two approaches,
regardless of the native endianness of the machine.</b> Optimizing compilers will likely
generate exactly the same code for both.</p>
<p>Now consider a slightly different problem:&nbsp; </p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111">
<tr>
<td colspan="2">Add a million values to a big endian value in a file, then write the
result to a file </td>
<td colspan="2"><i><b>Add a million values to a big endian value in a file, then write the
result to a file </b></i> </td>
</tr>
<tr>
<td><i><b>Endian type approach</b></i></td>
@ -246,7 +247,7 @@ big_int32_t x;
... read into x from a file ...
for (int32_t i = 0; i &lt; 1000000; ++i)
x += f(i);
x += i;
... write x to a file ...
</pre>
@ -260,7 +261,7 @@ int32_t x;
big_endian(x);
for (int32_t i = 0; i &lt; 1000000; ++i)
x += f(i);
x += i;
big_endian(x);
@ -270,10 +271,22 @@ big_endian(x);
</tr>
</table>
<p>There will be no performance difference. Optimizing compilers will likely
generate exactly the same code for both approaches.&nbsp; </p>
<p><b>There may or may not be a considerable performance difference, depending
on the endianness of the machine. </b>If machine endianness differs from the
desired endianness, the Endian type approach must do the byte reversal a million
times while the Endian conversion approach only does the reversal once. But if
the endianness is the same, there is no conversion with either approach and no
conversion code is generated for typical release builds.</p>
<h2>Timing tests</h2>
<p><b>If compiler byte swap intrinsics are not available, any timing differences
will be magnified.</b> Byte swap intrinsics are not available on some older
compilers and on some machine architectures, such as pre-486 X86 CPUs.</p>
<p><b>Unaligned types are much slower that aligned types, regardless of
endianness considerations.</b> Instead of single instruction register loads and
stores, multiple instructions are required.</p>
<h3>Timing tests</h3>
<p>These tests were run against release builds on a circa 2012 4-core little endian X64 Intel Core i5-3570K
CPU @ 3.40GHz under Windows 7.</p>

153
test/loop_time_test.cpp
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@ -9,7 +9,7 @@
#define _SCL_SECURE_NO_WARNINGS
//#define BOOST_ENDIAN_NO_INTRINSICS
#define BOOST_ENDIAN_NO_INTRINSICS
//#define BOOST_ENDIAN_LOG
#include <boost/endian/detail/disable_warnings.hpp>
@ -84,8 +84,9 @@ namespace
template <class T, class EndianT>
void time()
{
T total = 0;
{
cout << "*************Endian integer approach...\n";
// cout << "*************Endian integer approach...\n";
EndianT x(0);
boost::timer::cpu_timer t;
for (uint64_t i = 0; i < n; ++i)
@ -93,11 +94,11 @@ namespace
x += static_cast<T>(i);
}
t.stop();
cout << "x: " << x << endl;
total += x;
cout << "<td align=\"right\">" << t.format(places, "%t") << " s</td>";
}
{
cout << "***************Endian conversion approach...\n";
// cout << "***************Endian conversion approach...\n";
T x(0);
boost::timer::cpu_timer t;
big_endian(x);
@ -108,31 +109,41 @@ namespace
big_endian(x);
t.stop();
big_endian(x);
cout << "x: " << x << endl;
if (x != total)
throw std::logic_error("integer approach total != conversion approach total");
cout << "<td align=\"right\">" << t.format(places, "%t") << " s</td>";
}
}
//void test_big_int16()
//{
// cout << "<tr><td>16-bit aligned big endian</td>";
// time<int16_t, big_int16_t>(user::return_x_big_int16);
// time<int16_t, big_int16_t>(user::return_x_value_big_int16);
// time<int16_t, big_int16_t>(user::return_x_in_place_big_int16);
// time<int16_t, big_int16_t>(user::return_x_big_int16);
// cout << "</tr>\n";
//}
void test_big_int16()
{
cout << "<tr><td>16-bit aligned big endian</td>";
time<int16_t, big_int16_t>();
cout << "</tr>\n";
}
//void test_little_int16()
//{
// cout << "<tr><td>16-bit aligned little endian</td>";
// time<int16_t, little_int16_t>(user::return_x_little_int16);
// time<int16_t, little_int16_t>(user::return_x_value_little_int16);
// time<int16_t, little_int16_t>(user::return_x_in_place_little_int16);
// time<int16_t, little_int16_t>(user::return_x_little_int16);
// cout << "</tr>\n";
//}
void test_little_int16()
{
cout << "<tr><td>16-bit aligned little endian</td>";
time<int16_t, little_int16_t>();
cout << "</tr>\n";
}
void test_big_int16un()
{
cout << "<tr><td>16-bit unaligned big endian</td>";
time<int16_t, big_int16un_t>();
cout << "</tr>\n";
}
void test_little_int16un()
{
cout << "<tr><td>16-bit unaligned little endian</td>";
time<int16_t, little_int16un_t>();
cout << "</tr>\n";
}
void test_big_int32()
{
cout << "<tr><td>32-bit aligned big endian</td>";
@ -140,32 +151,54 @@ namespace
cout << "</tr>\n";
}
//void test_little_int32()
//{
// cout << "<tr><td>32-bit aligned little endian</td>";
// time<int32_t, little_int32_t>();
// cout << "</tr>\n";
//}
void test_little_int32()
{
cout << "<tr><td>32-bit aligned little endian</td>";
time<int32_t, little_int32_t>();
cout << "</tr>\n";
}
//void test_big_int64()
//{
// cout << "<tr><td>64-bit aligned big endian</td>";
// time<int64_t, big_int64_t>(user::return_x_big_int64);
// time<int64_t, big_int64_t>(user::return_x_value_big_int64);
// time<int64_t, big_int64_t>(user::return_x_in_place_big_int64);
// time<int64_t, big_int64_t>(user::return_x_big_int64);
// cout << "</tr>\n";
//}
void test_big_int32un()
{
cout << "<tr><td>32-bit unaligned big endian</td>";
time<int32_t, big_int32un_t>();
cout << "</tr>\n";
}
//void test_little_int64()
//{
// cout << "<tr><td>64-bit aligned little endian</td>";
// time<int64_t, little_int64_t>(user::return_x_little_int64);
// time<int64_t, little_int64_t>(user::return_x_value_little_int64);
// time<int64_t, little_int64_t>(user::return_x_in_place_little_int64);
// time<int64_t, little_int64_t>(user::return_x_little_int64);
// cout << "</tr>\n";
//}
void test_little_int32un()
{
cout << "<tr><td>32-bit unaligned little endian</td>";
time<int32_t, little_int32un_t>();
cout << "</tr>\n";
}
void test_big_int64()
{
cout << "<tr><td>64-bit aligned big endian</td>";
time<int64_t, big_int64_t>();
cout << "</tr>\n";
}
void test_little_int64()
{
cout << "<tr><td>64-bit aligned little endian</td>";
time<int64_t, little_int64_t>();
cout << "</tr>\n";
}
void test_big_int64un()
{
cout << "<tr><td>64-bit unaligned big endian</td>";
time<int64_t, big_int64un_t>();
cout << "</tr>\n";
}
void test_little_int64un()
{
cout << "<tr><td>64-bit unaligned little endian</td>";
time<int64_t, little_int64un_t>();
cout << "</tr>\n";
}
} // unnamed namespace
@ -176,7 +209,7 @@ int cpp_main(int argc, char* argv[])
process_command_line(argc, argv);
cout
<< "<html>\n<head>\n<title>Endian Speed Test</title>\n</head>\n<body>\n"
<< "<html>\n<head>\n<title>Endian Loop Time Test</title>\n</head>\n<body>\n"
<< "<table border=\"1\" cellpadding=\"5\" cellspacing=\"0\""
<< "style=\"border-collapse: collapse\" bordercolor=\"#111111\">\n"
<< "<tr><td colspan=\"6\" align=\"center\"><b>"
@ -186,19 +219,25 @@ int cpp_main(int argc, char* argv[])
<< ", Intrinsics: " BOOST_ENDIAN_INTRINSIC_MSG
<< "</b></td></tr>\n"
<< "<tr><td><b>Test Case</b></td>\n"
"<td align=\"center\"><b>int<br>arg</b></td>\n"
"<td align=\"center\"><b>int<br>value(arg)</b></td>\n"
"<td align=\"center\"><b>int<br>in place(arg)</b></td>\n"
"<td align=\"center\"><b>Endian<br>arg</b></td>\n"
"<td align=\"center\"><b>Endian<br>type</b></td>\n"
"<td align=\"center\"><b>Endian<br>conversion<br>function</b></td>\n"
"</tr>\n"
;
//test_big_int16();
//test_little_int16();
test_big_int16();
test_little_int16();
test_big_int16un();
test_little_int16un();
test_big_int32();
//test_little_int32();
//test_big_int64();
//test_little_int64();
test_little_int32();
test_big_int32un();
test_little_int32un();
test_big_int64();
test_little_int64();
test_big_int64un();
test_little_int64un();
cout << "\n</table>\n</body>\n</html>\n";

2
test/msvc2012/loop_time_test/loop_time_test.vcxproj
View File

@ -60,7 +60,7 @@
<GenerateDebugInformation>true</GenerateDebugInformation>
</Link>
<PostBuildEvent>
<Command>"$(TargetDir)\$(TargetName).exe" 1000</Command>
<Command>"$(TargetDir)\$(TargetName).exe" 1</Command>
</PostBuildEvent>
</ItemDefinitionGroup>
<ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">