Sequential Structure Layout For Speed
This code will Highlight Wise Choice for sequential layout Structure
We are going to declare a Matrix which is used to house a Set.. Explicitly. Just by putting the iteration value in the middle of the sequence you can speed up that example code by a factor of 36% !.. and that is just by adjusting the location of data in the memory....
The code below highlights the differences (there was a nice table here to show the differences... but it has been improved to be actual code (not it's intent, so I edited it out :( ) Nearly Full code is given below.
The thing to notice is that position of the class member i is in different places.. the reason this is so useful is that it highlights quite nicely the effect of cache misses... a quick look at the Compiler choice classes will show you where the differences are... And Here are the results from adding i to the matrix elements... (this was individually timed inside of a for loop 200 times, then a simple average was taken)... Total savings 0.0175 seconds! This was pitted against the CLR and CLR results are somewhere in between (as would be expected).
--Upgraded From My Blog.... :laugh:
Here is the Running code, The CompilerChoice classes are CLR layout comparisons (results not shown)
The thing to notice is that position of the class member i is in different places.. the reason this is so useful is that it highlights quite nicely the effect of cache misses... a quick look at the Compiler choice classes will show you where the differences are... And Here are the results from adding i to the matrix elements... (this was individually timed inside of a for loop 200 times, then a simple average was taken)... Total savings 0.0175 seconds! This was pitted against the CLR and CLR results are somewhere in between (as would be expected).
--Upgraded From My Blog.... :laugh:
Here is the Running code, The CompilerChoice classes are CLR layout comparisons (results not shown)
[StructLayout(LayoutKind.Explicit)]
public class PoorChoice
{
[FieldOffset(0)]
public int i;
[FieldOffset(4)]
public int m00;
[FieldOffset(8)]
public int m01;
[FieldOffset(16)]
public int m02;
[FieldOffset(20)]
public int m03;
[FieldOffset(24)]
public int m10;
[FieldOffset(28)]
public int m11;
[FieldOffset(32)]
public int m12;
[FieldOffset(36)]
public int m13;
[FieldOffset(40)]
public int m20;
[FieldOffset(44)]
public int m21;
[FieldOffset(48)]
public int m22;
[FieldOffset(52)]
public int m23;
[FieldOffset(56)]
public int m30;
[FieldOffset(60)]
public int m31;
[FieldOffset(64)]
public int m32;
[FieldOffset(68)]
public int m33;
}
[StructLayout(LayoutKind.Explicit)]
public class GreatChoice
{
[FieldOffset(0)]
public int m00;
[FieldOffset(4)]
public int m01;
[FieldOffset(8)]
public int m02;
[FieldOffset(12)]
public int m03;
[FieldOffset(16)]
public int m10;
[FieldOffset(20)]
public int m11;
[FieldOffset(24)]
public int m12;
[FieldOffset(28)]
public int m13;
[FieldOffset(32)]
public byte i;
[FieldOffset(33)]
public int m20;
[FieldOffset(37)]
public int m21;
[FieldOffset(41)]
public int m22;
[FieldOffset(45)]
public int m23;
[FieldOffset(49)]
public int m30;
[FieldOffset(53)]
public int m31;
[FieldOffset(57)]
public int m32;
[FieldOffset(61)]
public int m33;
}
public class CompilerChoice1
{
public int i;
public int m00;
public int m01;
public int m02;
public int m03;
public int m10;
public int m11;
public int m12;
public int m13;
public int m20;
public int m21;
public int m22;
public int m23;
public int m30;
public int m31;
public int m32;
public int m33;
}
public class CompilerChoice2
{
public int m00;
public int m01;
public int m02;
public int m03;
public int m10;
public int m11;
public int m12;
public int m13;
public byte i;
public int m20;
public int m21;
public int m22;
public int m23;
public int m30;
public int m31;
public int m32;
public int m33;
}
public GreatLayoutTest(System.Windows.Forms.Label label)
{
Console.WriteLine("the Size of Poor Choice is:" + System.Runtime.InteropServices.Marshal.SizeOf(typeof(PoorChoice)).ToString());
Console.WriteLine("the Size of Great Choice is:" + System.Runtime.InteropServices.Marshal.SizeOf(typeof(GreatChoice)).ToString());
//Type 'ThreadingBestPractices.CompilerChoice1' cannot be marshaled as an unmanaged structure; no meaningful size or offset can be computed."
//Console.WriteLine("the Size of Compiler Choice 1 is:" + System.Runtime.InteropServices.Marshal.SizeOf(typeof(CompilerChoice1)).ToString());
//Type 'ThreadingBestPractices.CompilerChoice1' cannot be marshaled as an unmanaged structure; no meaningful size or offset can be computed."
//Console.WriteLine("the Size of Compiler Choice 2 is:" + System.Runtime.InteropServices.Marshal.SizeOf(typeof(CompilerChoice2)).ToString());
List<double[]> ControlResults = new List<double[]>();
PoorLayout pl = new PoorLayout();
label.Text = pl.Test();
TimeSpan[] ts = new TimeSpan[2];
DateTime[] ts_start = new DateTime[2];
double[] duration = new double[4];
PoorChoice poor = new PoorChoice();
GreatChoice great = new GreatChoice();
CompilerChoice1 clr1 = new CompilerChoice1();
CompilerChoice2 clr2 = new CompilerChoice2();
for (int i = 0; i < 200; i++)
{
label.Text = (200 - i).ToString(); label.Refresh();
#region Poor
Stopwatch sw = Stopwatch.StartNew();
poor.m00 += poor.i;
poor.i++;
poor.m01 += poor.i;
poor.i++;
poor.m02 += poor.i;
poor.i++;
poor.m03 += poor.i;
poor.i++;
poor.m10 += poor.i;
poor.i++;
poor.m11 += poor.i;
poor.i++;
poor.m12 += poor.i;
poor.i++;
poor.m13 += poor.i;
poor.i++;
poor.m20 += poor.i;
poor.i++;
poor.m21 += poor.i;
poor.i++;
poor.m22 += poor.i;
poor.i++;
poor.m23 += poor.i;
poor.i++;
poor.m30 += poor.i;
poor.i++;
poor.m31 += poor.i;
poor.i++;
poor.m32 += poor.i;
poor.i++;
poor.m33 += poor.i;
poor.i++;
duration[0] = sw.Elapsed.TotalMilliseconds;
#endregion
#region great
sw = Stopwatch.StartNew();
great.m00 += great.i;
great.i++;
great.m01 += great.i;
great.i++;
great.m02 += great.i;
great.i++;
great.m03 += great.i;
great.i++;
great.m10 += great.i;
great.i++;
great.m11 += great.i;
great.i++;
great.m12 += great.i;
great.i++;
great.m13 += great.i;
great.i++;
great.m20 += great.i;
great.i++;
great.m21 += great.i;
great.i++;
great.m22 += great.i;
great.i++;
great.m23 += great.i;
great.i++;
great.m30 += great.i;
great.i++;
great.m31 += great.i;
great.i++;
great.m32 += great.i;
great.i++;
great.m33 += great.i;
great.i++;
duration[1] = sw.Elapsed.TotalMilliseconds;
#endregion
#region Compiler1
sw = Stopwatch.StartNew();
clr1.m00 += clr1.i;
clr1.i++;
clr1.m01 += clr1.i;
clr1.i++;
clr1.m02 += clr1.i;
clr1.i++;
clr1.m03 += clr1.i;
clr1.i++;
clr1.m10 += clr1.i;
clr1.i++;
clr1.m11 += clr1.i;
clr1.i++;
clr1.m12 += clr1.i;
clr1.i++;
clr1.m13 += clr1.i;
clr1.i++;
clr1.m20 += clr1.i;
clr1.i++;
clr1.m21 += clr1.i;
clr1.i++;
clr1.m22 += clr1.i;
clr1.i++;
clr1.m23 += clr1.i;
clr1.i++;
clr1.m30 += clr1.i;
clr1.i++;
clr1.m31 += clr1.i;
clr1.i++;
clr1.m32 += clr1.i;
clr1.i++;
clr1.m33 += clr1.i;
clr1.i++;
duration[2] = sw.Elapsed.TotalMilliseconds;
#endregion
#region Compiler2
sw = Stopwatch.StartNew();
clr2.m00 += clr2.i;
clr2.i++;
clr2.m01 += clr2.i;
clr2.i++;
clr2.m02 += clr2.i;
clr2.i++;
clr2.m03 += clr2.i;
clr2.i++;
clr2.m10 += clr2.i;
clr2.i++;
clr2.m11 += clr2.i;
clr2.i++;
clr2.m12 += clr2.i;
clr2.i++;
clr2.m13 += clr2.i;
clr2.i++;
clr2.m20 += clr2.i;
clr2.i++;
clr2.m21 += clr2.i;
clr2.i++;
clr2.m22 += clr2.i;
clr2.i++;
clr2.m23 += clr2.i;
clr2.i++;
clr2.m30 += clr2.i;
clr2.i++;
clr2.m31 += clr2.i;
clr2.i++;
clr2.m32 += clr2.i;
clr2.i++;
clr2.m33 += clr2.i;
clr2.i++;
duration[3] = sw.Elapsed.TotalMilliseconds;
#endregion
results.Add(new double[] {
duration[0],
duration[1],
duration[2],
duration[3]});
}
IO.WriteOut("GreatLayoutTest.txt", results);
label.Text = "Done";
}