Bit-level Parallelism Simplified

Manpreeth Sai
8 min readDec 7, 2022

Bit-level parallelism is a topic that comes reoccurs across the study of High Level Computing. In simple words, Bit-level Parallelism can be understood by assuming the process of eating food. Lets consider a family going out to a pizza den for dinner. The parents casually order a Large sized pizza for themselves and a small sized one for their son. Naturally once the pizza is served, the son takes smaller bites and takes a longer time to eat due to the smaller mouth size. Whereas, the parents might opt to eat slow but have the capability to eat faster by tearing into bigger bites. Now compare this situation to that of a computer’s processor. Since a smaller bit processor has to take smaller pieces of information to process a bigger sized input it will most definitely run longer.

“Since a smaller bit processor has to take smaller pieces of information to process a bigger sized input it will most definitely run longer. ”

A processor depiction

This is where Bit-level parallelism comes into the picture. By parallel computing: the process of computing several pieces of information simultaneously, large pieces of information can be broken into several smaller pieces and run at the same time, the processor word size is increased thereby allowing faster processing. In computational terms, lets take a scientific example to understand this concept. Assume a 16-bit processor supplied with two 32-bit integers. The processor will have to split the first 16 bits into lower order and next 16 bits into the upper order. Therefore, it will need two instructions to complete the whole process whereas a 32 bit processor would have completed the process in a single instruction. In the earlier days most computers were made of a single bit. Thereby their processing capacity was pretty slow and they couldn’t make complex calculations. Thanks to Bit-Level Parallelism, the advancement in computer architecture development got accelerated and helped develop it faster.

“Assume a 16-bit processor supplied with two 32-bit integers. The processor will have to split the first 16 bits into lower order and next 16 bits into the upper order.”

By increasing the bit-level, 4-bits transformed into 8-bits. It soon shifted to 16-bits, and finally to 32-bits. Soon, 32 bits became a standard for all the computers as most of them were equipped with 32-bits. After 2 decades, the computer architecture got introduced to the 64-bit world all thanks to the Nintendo 64 in 1996. It was a revelation and a computing beauty all by itself. It was world re-known and respected by all the Tech geeks across all nations.

The Nintendo 64 was the first of its kind.

It was a revelation and a computing beauty all by itself. It was world re-known and respected by all the Tech geeks across all nations.

There are several levels to general parallelism that we need to understand to get a clearer look at the bigger picture.

Instruction Level — A grain is considered to be fine if it contains fewer than 20 instructions. Depending on the particular software, fine-grain parallelism at this level could range from two thousand. Although the average parallelism at the instruction level is approximately fine, hardly ever exceeding seven in a typical program, the single instruction stream parallelism is larger than two.

In an optimal context, the typical parallel for scientific applications ranges from 500 to 300 Fortran statements running simultaneously.

Loop Level- It embraces iterative loop activities at the loop level. There is no limit to the number of instructions in a loop. For pipelined execution or look step execution on SIMD computers, several loop independent actions can be vectorized.

The most efficient program generation for a parallel or vector computer is loop level parallelism. Recursive loops, however, are harder to parallelize. By using a vectorizing compiler, vector processing is mostly utilised at the loop level.

Procedural Level — It communicates at the task, process, and subroutine levels with medium grain size. There are fewer than 2000 instructions in grain at this level. Parallelism detection at this grain level is substantially more challenging than it is at a finer grain level.

Compared to the MIMD execution model, there is substantially less of a communication duty. However, to rearrange a program at this level, the programmer must make significant efforts.

Subprogram Level: Subprogram level connects with relevant subprograms and task phases. Here, the grain size contains fewer than 1000 instructions. Steps in several jobs can cross across. At this level, multiprocessor or uniprocessor multiprogramming is done.

Job Level: This describes how independent jobs are carried out in parallel on a parallel computer. In this case, the grain size may be hundreds of instructions. The operating framework and the software loader are in charge of managing it. Multiprocessors with time- and space-sharing capabilities examine this level of parallelism.

In the broad terms of parallel computing, there are other types as well. Parallelism constitutes of other types other than Bit-level parallelism as well. Instruction Level Parallelism and Task Parallelism are two other variations known in parallel computing.

Instruction-Level Parallelism:

In this kind of parallel computing, the processor chooses the sequence and timing of the parallel execution of instructions. Additionally, it chooses how many instructions to process and execute concurrently. Since the compiler can only address a small number of instructions in instruction-level parallelism, which relies on static parallelism, it is crucial to be able to group the instructions and execute them concurrently without affecting the outcomes. There are certain architectures to Instruction- Level Parallelism,

  1. Sequential architecture 2.Dependence architecture 3.Independence architecture.

2. Here, the program is not expected to explicitly communicate any parallelism-related hardware information, such as superscalar architecture.

3. Here, the program makes explicit reference to knowledge about inter operational dependencies, such as dataflow architecture.

4. Here, the program informs the user which operations are independent of one another and can be carried out in place of the “nop”s.

Task Parallelism:

In this type of parallel computing, the tasks are divided into smaller tasks, or subtasks, and distributed to several processors. These processors then execute the components simultaneously while using the same data source.

In today’s world, the parallelism is used in multiple places throughout many industries. Such as phones and computers the places vary in many sectors.

In today’s world the advancement thanks to parallelism is immense. The process of development has been accelerated all thanks to the four fold increment in the flourishing of Parallelism. Laptops, Phones most things have it integrated in them nowadays.

Laptops
Think about your laptop right now. Once more, your laptop from the past might have been excruciatingly slow compared to your PC today. But thanks in part to parallel computing, we now have far faster gadgets. Processes are carried out simultaneously on modern Intel Core processors, which power many of the computers we use today, making them that much faster and more effective.

Smartphones
Consider the earliest smartphones from more than ten years ago. Recall how sluggish your iPhone 4 was? How long did it take for an app to load? This occurs almost instantly today, depending on your connection, especially when compared to the “good old days” — way back in 2010.

This is due to the fact that modern smartphones use parallel processing, in contrast to the serial computing-based cellphones of the past. Tasks are completed concurrently, which speeds up processing significantly.

“Internet of Things” (IoT)
The IoT is a vast network that improves the ease of modern life. Think about all of your smart gadgets, such as your voice assistants, cars, thermostats, doorbells, slow cookers, light switches, and slow cookers. The IoT includes all of these. Devices interact with one another and perform tasks via networks without the need for direct human intervention.

What is the IoT dependent upon? That’s right, parallel computing. This network generates tremendous amounts of data, which is processed with incredible speed because to this idea.

Some other places to keep in mind about the uses,

  1. Augmented reality

2.Blockchain
3.Data mining
4.Multithreading

5.Supercomputers

What will happen with parallel computing next? By now, it should be obvious that this idea is gaining ground and gradually displacing serial computing due to its effectiveness and enormous popularity. Many of the most well-known tech firms and operating system distributors are embracing the idea as the world continues to change.

The trend of the development of Microprocessor

The value of parallel processing

Last but not least, parallel computing is a crucial tool in scientific research, particularly in the area of simulations where complicated calculations and procedures needing a lot of processing power are performed. It can be used to build various models, including mathematical, statistical, meteorological, and even medical imagery. Other pertinent examples include servers, real-time systems, AI, and graphics processing. Because they enable multiple users to connect to the same service at once, multicore CPU’s are perfect for these latter applications (for example, in the case of a web server).

Because they enable multiple users to connect to the same service at once,

Parallel computing became established as the preeminent paradigm mostly due to this reason. The fact that the majority of modern computers — from supercomputers to desktop computers — are multicore is proof of this. Even some smartphones have eight cores or more (processors).

Given the current direction, it is simple to forecast that future processors will continue to be multicore with a variety of processing components that never stop expanding; this is especially true when you consider how much more important having a high processing capacity is.

Algorithms for matching strings are also fundamental parts of many software programmes. Additionally, they emphasise
programming techniques that are paradigms for other computer science disciplines. Additionally, they contribute significantly to theoretical computer science by posing difficult challenges.

How many operations in one instruction are paralleled by the instruction-level parallelism (ILP).
One or more algorithms can run concurrently. Common programmes typically developed using a sequential execution model, where commands are carried out in order
one after the other and in the order that the programmer has designated. ILP permits one to combine the execution of several commands, or even to alter the sequence in which commands are carried out. How much ILP is included into various programmes greatly varies by application. ILP is widely used in some industries, including graphics and scientific computing. However, tasks like cryptography show considerably less parallelism.

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