Our application uses plenty of dictionaries which have multi level lookup that are not frequently changing. We are investigating at converting some of the critical code that does a lot of lookup using dictionaries to use alternate structures for - faster lookup, light on the memory/gc. This made us compare various dictionaries/libraries available -
Dictionary(System.Collections.Generics.Dictionary-SCGD), ImmutableDictionary, C5.HashDictionary, FSharpMap.
Running the following program with various items count - 100, 1000, 10000, 100000 - shows that Dictionary is still the winner at most ranges. First row indicates items in collection. MS/Ticks would the time taken to perform x lookups randomized (code is below).
Items - 100
SCGD - 0 MS - 50 Ticks
C5 - 1 MS - 1767 Ticks
Imm - 4 MS - 5951 Ticks
FS - 0 MS - 240 Ticks
Items - 1000
SCGD - 0 MS - 230 Ticks
C5 - 0 MS - 496 Ticks
Imm - 0 MS - 1046 Ticks
FS - 1 MS - 1870 Ticks
Items - 10000
SCGD - 3 MS - 4722 Ticks
C5 - 4 MS - 6370 Ticks
Imm - 9 MS - 13119 Ticks
FS - 15 MS - 22050 Ticks
Items - 100000
SCGD - 62 MS - 89276 Ticks
C5 - 72 MS - 103658 Ticks
Imm - 172 MS - 246247 Ticks
FS - 249 MS - 356176 Ticks
Does this mean, we are already using the fastest and don't have to change? I had presumed that immutable structures should be at the top of table, but it wasn't that way. Are we doing wrong comparison or am I missing something? Was holding on to this question, but felt, its better to ask. Any link or notes or any references that throws some light will be great.
Complete code for test -
namespace CollectionsTest
{
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Runtime;
using Microsoft.FSharp.Collections;
/// <summary>
///
/// </summary>
class Program
{
static Program()
{
ProfileOptimization.SetProfileRoot(@".\Jit");
ProfileOptimization.StartProfile("Startup.Profile");
}
/// <summary>
/// Mains the specified args.
/// </summary>
/// <param name="args">The args.</param>
static void Main(string[] args)
{
// INIT TEST DATA ------------------------------------------------------------------------------------------------
foreach (int MAXITEMS in new int[] { 100, 1000, 10000, 100000 })
{
Console.WriteLine("\n# - {0}", MAXITEMS);
List<string> accessIndex = new List<string>(MAXITEMS);
List<KeyValuePair<string, object>> listofkvps = new List<KeyValuePair<string, object>>();
List<Tuple<string, object>> listoftuples = new List<Tuple<string, object>>();
for (int i = 0; i < MAXITEMS; i++)
{
listoftuples.Add(new Tuple<string, object>(i.ToString(), i));
listofkvps.Add(new KeyValuePair<string, object>(i.ToString(), i));
accessIndex.Add(i.ToString());
}
// Randomize for lookups
Random r = new Random(Environment.TickCount);
List<string> randomIndexesList = new List<string>(MAXITEMS);
while (accessIndex.Count > 0)
{
int index = r.Next(accessIndex.Count);
string value = accessIndex[index];
accessIndex.RemoveAt(index);
randomIndexesList.Add(value);
}
// Convert to array for best perf
string[] randomIndexes = randomIndexesList.ToArray();
// LOAD ------------------------------------------------------------------------------------------------
// IMMU
ImmutableDictionary<string, object> idictionary = ImmutableDictionary.Create<string, object>(listofkvps);
//Console.WriteLine(idictionary.Count);
// SCGD
Dictionary<string, object> dictionary = new Dictionary<string, object>();
for (int i = 0; i < MAXITEMS; i++)
{
dictionary.Add(i.ToString(), i);
}
//Console.WriteLine(dictionary.Count);
// C5
C5.HashDictionary<string, object> c5dictionary = new C5.HashDictionary<string, object>();
for (int i = 0; i < MAXITEMS; i++)
{
c5dictionary.Add(i.ToString(), i);
}
//Console.WriteLine(c5dictionary.Count);
// how to change to readonly?
// F#
FSharpMap<string, object> fdictionary = new FSharpMap<string, object>(listoftuples);
//Console.WriteLine(fdictionary.Count);
// TEST ------------------------------------------------------------------------------------------------
Stopwatch sw = Stopwatch.StartNew();
for (int index = 0, indexMax = randomIndexes.Length; index < indexMax; index++)
{
string i = randomIndexes[index];
object value;
dictionary.TryGetValue(i, out value);
}
sw.Stop();
Console.WriteLine("SCGD - {0,10} MS - {1,10} Ticks", sw.ElapsedMilliseconds, sw.ElapsedTicks);
Stopwatch c5sw = Stopwatch.StartNew();
for (int index = 0, indexMax = randomIndexes.Length; index < indexMax; index++)
{
string key = randomIndexes[index];
object value;
c5dictionary.Find(ref key, out value);
}
c5sw.Stop();
Console.WriteLine("C5 - {0,10} MS - {1,10} Ticks", c5sw.ElapsedMilliseconds, c5sw.ElapsedTicks);
Stopwatch isw = Stopwatch.StartNew();
for (int index = 0, indexMax = randomIndexes.Length; index < indexMax; index++)
{
string i = randomIndexes[index];
object value;
idictionary.TryGetValue(i, out value);
}
isw.Stop();
Console.WriteLine("Imm - {0,10} MS - {1,10} Ticks", isw.ElapsedMilliseconds, isw.ElapsedTicks);
Stopwatch fsw = Stopwatch.StartNew();
for (int index = 0, indexMax = randomIndexes.Length; index < indexMax; index++)
{
string i = randomIndexes[index];
fdictionary.TryFind(i);
}
fsw.Stop();
Console.WriteLine("FS - {0,10} MS - {1,10} Ticks", fsw.ElapsedMilliseconds, fsw.ElapsedTicks);
}
}
}
}
