diff --git a/src/vs/platform/instantiation/common/instantiation.ts b/src/vs/platform/instantiation/common/instantiation.ts
index 3ba10958d2f..6b44bbf29e6 100644
--- a/src/vs/platform/instantiation/common/instantiation.ts
+++ b/src/vs/platform/instantiation/common/instantiation.ts
@@ -12,6 +12,8 @@ import * as descriptors from './descriptors';
 
 export namespace _util {
 
+	export const serviceIds = new Map<string, ServiceIdentifier<any>>();
+
 	export const DI_TARGET = '$di$target';
 	export const DI_DEPENDENCIES = '$di$dependencies';
 
@@ -98,7 +100,7 @@ export interface IFunctionSignature8<A1, A2, A3, A4, A5, A6, A7, A8, R> {
 	(accessor: ServicesAccessor, first: A1, second: A2, third: A3, forth: A4, fifth: A5, sixth: A6, seventh: A7, eigth: A8): R;
 }
 
-export var IInstantiationService = createDecorator<IInstantiationService>('instantiationService');
+export const IInstantiationService = createDecorator<IInstantiationService>('instantiationService');
 
 export interface IInstantiationService {
 
@@ -185,7 +187,11 @@ function storeServiceDependency(id: Function, target: Function, index: number, o
  */
 export function createDecorator<T>(serviceId: string): { (...args: any[]): void; type: T; } {
 
-	let id = function (target: Function, key: string, index: number): any {
+	if (_util.serviceIds.has(serviceId)) {
+		return _util.serviceIds.get(serviceId);
+	}
+
+	const id = <any>function (target: Function, key: string, index: number): any {
 		if (arguments.length !== 3) {
 			throw new Error('@IServiceName-decorator can only be used to decorate a parameter');
 		}
@@ -194,7 +200,8 @@ export function createDecorator<T>(serviceId: string): { (...args: any[]): void;
 
 	id.toString = () => serviceId;
 
-	return <any>id;
+	_util.serviceIds.set(serviceId, id);
+	return id;
 }
 
 /**
diff --git a/src/vs/platform/instantiation/common/serviceCollection.ts b/src/vs/platform/instantiation/common/serviceCollection.ts
index edb460d4dbb..4942626bd9f 100644
--- a/src/vs/platform/instantiation/common/serviceCollection.ts
+++ b/src/vs/platform/instantiation/common/serviceCollection.ts
@@ -4,7 +4,6 @@
  *--------------------------------------------------------------------------------------------*/
 'use strict';
 
-import { binarySearch } from 'vs/base/common/arrays';
 import { ServiceIdentifier } from 'vs/platform/instantiation/common/instantiation';
 import { SyncDescriptor } from './descriptors';
 
@@ -12,61 +11,29 @@ type Entry = [ServiceIdentifier<any>, any];
 
 export class ServiceCollection {
 
-	private _entries: Entry[] = [];
+	private _entries = new Map<ServiceIdentifier<any>, any>();
 
 	constructor(...entries: [ServiceIdentifier<any>, any][]) {
-		for (let entry of entries) {
-			this.set(entry[0], entry[1]);
+		for (let [id, service] of entries) {
+			this.set(id, service);
 		}
 	}
 
 	set<T>(id: ServiceIdentifier<T>, instanceOrDescriptor: T | SyncDescriptor<T>): T | SyncDescriptor<T> {
-		const entry: Entry = [id, instanceOrDescriptor];
-		const idx = binarySearch(this._entries, entry, ServiceCollection._entryCompare);
-		if (idx < 0) {
-			// new element
-			this._entries.splice(~idx, 0, entry);
-		} else {
-			const old = this._entries[idx];
-			this._entries[idx] = entry;
-			return old[1];
-		}
+		const result = this._entries.get(id);
+		this._entries.set(id, instanceOrDescriptor);
+		return result;
 	}
 
 	forEach(callback: (id: ServiceIdentifier<any>, instanceOrDescriptor: any) => any): void {
-		for (let entry of this._entries) {
-			let [id, instanceOrDescriptor] = entry;
-			callback(id, instanceOrDescriptor);
-		}
+		this._entries.forEach((value, key) => callback(key, value));
 	}
 
 	has(id: ServiceIdentifier<any>): boolean {
-		return binarySearch(this._entries, ServiceCollection._searchEntry(id), ServiceCollection._entryCompare) >= 0;
+		return this._entries.has(id);
 	}
 
 	get<T>(id: ServiceIdentifier<T>): T | SyncDescriptor<T> {
-		const idx = binarySearch(this._entries, ServiceCollection._searchEntry(id), ServiceCollection._entryCompare);
-		if (idx >= 0) {
-			return this._entries[idx][1];
-		}
-	}
-
-	private static _dummy: Entry = [undefined, undefined];
-
-	private static _searchEntry(id: ServiceIdentifier<any>): Entry {
-		ServiceCollection._dummy[0] = id;
-		return ServiceCollection._dummy;
-	}
-
-	private static _entryCompare(a: Entry, b: Entry): number {
-		const _a = a[0].toString();
-		const _b = b[0].toString();
-		if (_a < _b) {
-			return -1;
-		} else if (_a > _b) {
-			return 1;
-		} else {
-			return 0;
-		}
+		return this._entries.get(id);
 	}
 }