Multithread and Multiprocess

Multithreading

Advantages of Multithreading

• When tasks that were previously handled concurrently using processes are implemented with threads, memory space and system resource consumption are reduced

• When communication between threads is needed, instead of using separate resources, data can be exchanged using the global variable space or the dynamically allocated Heap area

  • Therefore, inter-thread communication methods are much simpler compared to inter-process communication methods

• A thread's context switch is faster than a process's context switch because there is no need to flush the cache memory

  • As a result, the system's throughput improves,

  • resource consumption decreases,

  • and the program's response time naturally shortens

• Because of these advantages, tasks are divided into threads within a single process

Problems with Multithreading

• When programming based on multi-process, there are no shared resources between processes, so there is no situation where the same resource is accessed simultaneously. However, when programming based on multi-threading, this must be taken into account

  • Since different threads share data and heap areas, one thread may access variables or data structures being used by another thread and read or modify incorrect values

• Therefore, synchronization is necessary in a multi-threading environment

  • Synchronization controls the order of task processing and access to shared resources.

    • but, this can lead to bottleneck issues, which increases the likelihood of performance degradation

      • Therefore, bottlenecks caused by excessive locks should be reduced

• In a multi-thread environment, when multiple threads try to share a single resource, problems such as Deadlock can occur

Multithread vs Multiprocess

• Multi-thread

  • Advantages

    • Multi-threading occupies less space than multi-process and has faster context switching,

  • Disadvantages

    • If one thread terminates due to an error, all threads may terminate, and

    • It has synchronization issues

• Multi-process

  • Advantages

    • In the multi-process approach, even if one process dies, other processes are not affected and continue to run normally,

  • Disadvantages

    • It requires more memory space and CPU time than multi-threading

• Summary

  • Multi-thread and multi-process are the same in that they perform multiple tasks simultaneously,

    • but they are suited or unsuited depending on the system they are applied to

  • Therefore, the appropriate operating method should be selected and applied based on the characteristics of the target system