Before multicore processors became mainstream, there was a popular model called Symmetric Multiprocessing (SMP). This model was in vogue in 1990's.

An SMP architecture is one where two or more IDENTICAL  processors are connected through a SHARED common memory. Each processor has equal access to the shared memory (they have  same  latency to the memory). This is differnet from a  Non-Uniform Memory Access (NUMA) architecture, where each processor has its own local memory but also has access to shared memory with a different access latency.

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We have seen the challenges of multicore programming in mainstream programming in earlier articles.

The main  challenge is refactoring of the code to multiple parallel threads of execution that can run on different cores and in the process, how to address the issues of synchronization, race conditions effectively.

But if there are no synchronizations needed between the parallel threads, it becomes easy and even natural to adopt parallel programming on multicore.

We have seen some such areas like networking and scientific computing. Server side processing is another such area......

Networking gear companies are bullish about the multicore processors and are seeing tangible benefits from them. Let us look at the reasons for the same.

If we look at a networking equipment like router it has two broad components: the data plane and  control plane

The data plane is also referred as the fast path. This is the code that gets executed when a packet (like ethernet packet) comes on an interface like ethernet port. It is a real-time task and throughput of the system depends on this code. It is not a complex logic but it is typically handcrafted for higher throughpu......

Recently, scientists from NCSU have discovered a  technique that improves performance of  applications up to 20% on a multicore system. And the technique does not need any change in existing code.

To understand its significance, we should first answer the question “why it is difficult  to parallelize a desktop application?”.

If we take a word processing application as an example, it will have a  loop waiting for a key to be pressed,  and when it is pressed, it applies the format/styles to the character, displays the character on screen and retur......

Dear Readers,

In the last article, we saw about the so called “embrassingly parallel operations” which can easily take advantage of multicore systems. In this article, let us see one more way of getting performance improvements on multicore systems. OpenMP is one of them.

OpenMP specifications was originally defined by industry vendors like Sun, Intel in 1997. It was popular in Symmetric Multiprocessing (SMP) systems. A typical SMP system is a multiprocessor computer hardware where two or more identical processors are connected to a single shared memory and......

Dear Readers,

In the last article, we saw the difficulties in concurrent programming. The difficulties arise due to the complex interplay of different threads of execution, how they communicate with each other and how they access common variables.

But there are some cases, where this is NOT an issue.

Suppose there is an array of 1000000 bytes which has to be initialized with zeros. We can have a program that sequentially fills the array with zero. Or we can create multiple threads, and allow them to initialize different parts of the array. Since the threads w......

Dear Readers,

In the last article, we saw how the semiconductor industry has hit the wall in increasing the CPU speeds and how the onus of performance improvements is getting shifted to software community. In this article, let us see difficulties for software folks in taking advantage of the multiple cores.

If a CPU has a single core, there is only one unit of execution. But if we have more than one core and if the software has to use them effectively, then software has to move to concurrent programming model.

What this means is that software should be broken into......

Multicore processors are processors which have more than one core inside. Today, it is not uncommon to have desktops having two or four cores. This trend is picking up and will only accelerate in coming years. There is a background to the raising popularity of multicore technologies. Even more important is the impact multicore is going to have on the mainstream programming.

If we look at the semiconductor industry, Moore's law has held its sway over the last two decades. Though it is still holding good, there has been a perceptible slow down recently. Moore's law says that the number of trans......