Somehow I came across this company that provides some crazy numbers in just one rack. Then again nearly by coincidence I show this news from an email that mentioned “cerebras” and wafer-scale, a term that I have never heard about it. So found some info in wikipedia and all looks like amazing. As well, I have learned about Gene Amdahl as he was the first one trying wafer-scale integration and his law. Didnt know he was such a figure in the computer architecture history.

VMware Co-stop / LPM in hardware

This is a very interesting article about how Longest Prefix Matching is done in networks chips. I remember reading about bloom filters in some Cloudfare blog but I didnt think that would be use too in network chips. As well, I forgot how critical is LPM in networking.

I had to deal lately with some performance issues with an application running in a VM. I am quite a noob regarding virtualization and always assumed the bigger the VM the better (very masculine thing I guess…) But a virtualization expert at work explained me issues regarding that assumption with this link. I learnt a lot from it (still a noob though). But I agree that I see most vendors asking for crazy requirements when offering products to run in VM…. and that looks like that kills that idea itself of having a virtualization environment because that VM looks like requires a dedicated server…. So right-sizing your product/VM is very important. I agree with the statement that vendors dont really do load testing for their VM offering and the high requirements it is an excuse to “avoid” problems from customers.

Analog Computing

This is an interesting video about how we can use analog computing. It seems a good use in matrix calculation used in AI.

All our technology is digital but we are reaching limits (power usage, physical limits, etc) and the “boom” in AI seems to benefit from analog computing.


I have been reading this book during my lunch brakes for several month. Most of the times just a couple of pages to be honest as generally my knowledge of CPU architecture is very poor. I really enjoyed this subject in Uni and this book was one of my favourites during that time. It was like a bible of CPU architecture. And Patterson is an author in both books.

I remember that there were too main architectures RISC vs CISC. In a very summarize way, RISC were simple instruction that were easy to parallelized and executed (with more instructions to execute) and CISC were complex instruction (few to execute) but that were difficult to scale. So let’s say simplicity (RISC) “won” the race in CPU architecture.

RISC-V is an open standard so anybody can produce CPUs for executing those instruction. So you can easily get your hands dirty getting a board.

One of the reason of RISC-V is to learn from all the architectures mistakes and provide a design that works for any type of processor (embedded to super-computers), is efficient, modular and stable.

The book compares RISC-V with current ISAS from ARM-32, MIPS-32, Intel x86-32, etc. Based on cost, simplicity, performance , isolation from implementation, room for growth, code size and ease of programming.

There were many parts of the book that I couldn’t really understand but I found the chapter 8 quite interesting. This is about how to compute data concurrently. The best know architecture is Single Instruction Multiple Data (SIMD). The alternative is Vector architecture. And this is used in RISC-V. The implementation details are too our of my league.

In summary, it was a nice read to refresh a bit my CPU architecture knowledge.