Add new section about performance in multithreading

Author: abhinav-nath

README.md

@@ -17,6 +17,10 @@ Simple and easy to understand code examples for most of the Concurrent APIs prov
 - [Thread Signalling](./src/com/codecafe/concurrency/threadsignalling)
 - [Daemon Threads](./notes/daemon-threads.md) - [[code](./src/com/codecafe/concurrency/thread/daemonthreads/Main.java)]
 
+#### [Performance in Multithreading](./notes/performance-in-multithreading.md)
+- Latency
+- Throughput
+
 #### Thread synchronization and locks
 - [The `synchronized` keyword](./src/com/codecafe/concurrency/_synchronized)
 - [Locks](./src/com/codecafe/concurrency/locks)

images/latency_1.png

@@ -0,0 +1,21 @@
+# Performance in Multithreading
+
+There are two main criteria for performance in multithreaded applications:
+
+1. **Latency** - The time to completion of a task. Measured in _time_ units.
+2. **Throughput** - The amount of tasks completed in a given period. Measured in _tasks/time_ unit.
+
+## Latency
+
+Suppose we have a single task which can be completed by a single thread sequentially within time T
+
+![Latency](../images/latency_1.png)
+
+We can first break the task into multiple independent tasks
+
+![Latency](../images/latency_2.png)
+
+Then we can schedule these sub-tasks to run in parallel to each other in different threads,
+and theoretically we want to achieve the latency of `T/N` (N = number of sub-tasks).
+
+![Latency](../images/latency_3.png)