Turned on by COTSon

A few months ago, I wrote an article longing for the need of a multicore processor simulator - preferably one that is free. One of the reader of my blog have left a message about COTSon (I wonder why (s)he wanted to be anonymous). So I started reading more about it, starting with the white paper that was in SIGOPS. And I liked what I read.

COTSon is the result of a collaborative effort by HP and AMD. The best part about COTSon is that it is not just a multicore processor simulator, but can also act as a full blown system simulator. That means it can simulate a range of hardware models and software stack. It is based on AMD SimNow, which performs high speed instruction set translation for x86 and AMD Athelon type processors. The software stack that it can simulate includes everything that runs on x86 and AMD Athelon including proprietary software like MATLAB for instance.

What COTSon does is not a cycle-accurate or bit-accurate simulation, which runs over the entire weekend to tell what is wrong. Rather it's a fully functional simulation. So may be COTSon can act as a first cut simulation at one level higher than the Transaction Level Modeling. Or on the other hand, COTSon can be used as a tool to visualize the paradigms of TLM. Maybe COTSon is what we need in the design cycle in this world where time-to-market is of prime importance.

I am now interacting with a friend doing his doctorate in Vrije University about COTSon, how we can learn how to use it and use it. We would know the reality only when the rubber hits the road. Lets see how good it is and I will post at the end of my analysis with some greater detail.

I still don't know how Core i7 is made!

Here is an interesting video on the making of Intel Core i7. It starts off well, but slowly it becomes more of a marketing video than a technical video. It gives an overview of the architecture, but I was looking for an in depth analysis of the microarchitecture with design decisions and why they were made. It disappointed me. Anyway it is a good video for a high-level picture and it's worth watching.

India Microprocessor - Sensibility with no Sense

The top scientists in India are going to convene together in a project to make India Microprocessor. Network security has become a hot topic in many country's security meets thanks to Chinese hackers. Chinese hackers have broken into several governmental networks over the past few years. They managed to take down Russian consulate website and made nearly 70000 attempts on a single day to penetrate into NYPD network.

“History has shown that the need for defence[sic] security has sparked a chip industry in most nations,” she [Poornima Shenoy, the president of Indian Semiconductor Association] said.
Unlike the US and China, India still does not have chip-making technology, and Zerone seeks to change that.

Ms. Shenoy is true about the history. Not just microprocessor, about everything that we use now from Internet to mobile phone has been the output of the need for defense security. India is fundamentally afraid that it might be denied the microprocessor technology at one point of time. India has not produced any evidence for that suspicion. It might be confidential. Are we going to develop our own mobile phones, going by the same logic?

The entire story would make sense, if it is some nascent technology like nanotechnology based carbon chips or biological influence in IC manufacturing. Microprocessor technology is something that is place for the past 3-4 decades. The SPARC RISC processor architecture that they are planning to follow came in 1986. I am not taking anything away from the SPARC architecture. The point is just that it is not what can be called cutting-edge. This raises a lot of questions.

Why should suddenly a country decide to invest on developing a new processor? Instead it can better encourage the companies in India to make them. What happens when the processor technology changes or the processor proves to be inefficient in SPEC benchmark? Those who know history would be aware that there are many failure stories in processor technologies. Is India going to build its own fab to fabricate this processor? Actually building a fab just to fabricate a single kind of chip is a big waste of money. It may take even up to 40 years to recover that money. What if the processor technology falls behind in the test of time? Is India planning to build subsequent versions? That would mean keeping a permanent research team in payroll. Just convening a set of passionate designers is different from keeping them together permanently. In 1994, Intel's Pentium processor had a small bug with its FPU when floating point division was performed. Intel incurred a huge loss to fix the bug and replace all the sold processors. Would India Inc. do the same?

The argument may sound like questioning the country's ability to make microprocessors. I do not think that all government run science projects are inefficient. I rather feel that it should channel their effort in exploring new cryptographic algorithms, if it wants to improve network security and in socially progressive technologies like clean energy for instance. Building general purpose microprocessors in India can better be left out to private firms, by just providing them necessary facilities. And Intel did develop the first Made-in-India microprocessor.

Unless India has its own microprocessor, we can never ensure that networks (that require microprocessors) such as telecom, Army WAN, and microprocessors used in BARC, ISRO, in aircraft such as Tejas, battle tanks and radars are not compromised,” the document points out.

The entire argument is about India not investing directly in the making of general-purpose processor - the one that we use in PCs and game consoles. I think Tejas battletank and RADARs would be using application-specific embedded processors, microcontrollers, and digital signal processors. I don't think and I would not prescribe using general purpose microprocessors for battletanks. Making of these chips indigenously is a completely different ball game and it would make sense if India invests on this directly.

India directly putting bucks on general-purpose processor architecture might make bold headlines. TV channels might insist that Indian citizens should feel proud of that achievement. What may be the most sensible news for media, makes no sense for me as an engineer.