ARM server future

While talking about ARM server future, Calxeda should be considered first who initially jumped into ARM server fray. Calxeda EnergyCore ECX-1000 (based on the ARMv7 spec and only support 32-bit processing and memory addressing and 4GB memory) were introduced in November 2011. This year Calxeda is planning a Cortex-A15 core.It's chip code named "Midway" and supports 40-bit memory addressing and the memory to 16GB. This chip claims to be having twice the performance and enhanced virtualization. In 2014 they will make a move to the ARMv8 core with its "Lago" system-on-chip, providing 64-bit processing and memory addressing. Lago will help to double the performance of the processor and more than 100,000 nodes. Moreover, an ARM SoC from Calxeda called "Ratamosa" aimed at full-on enterprise applications and supercomputing workloads will also have performance enhancements.

Applied Micro wanted to be first with 64-bit ARM servers with ARM chip suitable for modern, cloudy servers .They launched X-Gene multi-core SoC based on ARMv8 design in October 2011. Initial X-Gene chip is supposed to sample in the first quarter of 2013 with being in market at the end of this year.

Marvell, Nvidia, AMD, Cavium and Samsung are also runners in the competitions although not so solid announcements made by these companies.

Many companies are working on  processors and interconnects.  So open source Linux operating system might be natural fit for the ARM chips.Chip developers and software providers can get help from Linux easily.

HP Project Moonshot

Hewlett-Packard (HP) had announced server cluster with the use of EnergyCore ARM RISC server chip. This hyperscale server is known as Project Moonshot. Redstone is going to be the first server platform under this project. HP states Project Moonshot as a extension to their previous ProLiant and Integrity server lines and not a replacement.

Moonshot is going to include superdense servers based on Intel low power Xeon and Atom chips and Advanced Micro Devices low-power x86 processors as well as multiple  ARM-based server chips.

Redstone is going to use Calxeda chips. Right now Redstone has 32 bit chips and HP says many customers think it’s fine. These chips can be targeted for web serving, web caching and data chewing workloads. 

The half rack of Redstone machines will be providing 1600 server nodes and will have 41 cables using 9.9 kwatts for $1.2m compared to traditional x86 based cluster with 10 rack space, 1600 cables using 91 kwatt for $3.3m. These numbers are impressive but the big caveat is, it will work for the workloads that can scale well on a modestly clocked (1.1GHz or 1.4GHz), four-core server chip which works only with 32-bits and has 4GB of memory.

ARM and x86 for portable devices and clouds (1)

New data center services for mobile platforms have increased demand for micro servers. the demand increase is triple in 2013 and according to research firm IHS iSuppli; the demand is going to increase in next five years.

For server design, maintenance, expandability, energy efficiency and low cost are important factors. Although Intel unveiled and reference the micro server concep, ARM architecture is gaining greater support from software and OS vendors which could put pressure on Intel.

Data centers spend 50% of the cost on power which can be reduced by using ARM architecture. ARM chips consume dramatically low power than x86 chips.ARM architectures are good for cloud computing in terms of following points. One is Scale-out workloads. Because of capability of ARM doing parallel processing very well, it is good match for large loads of data analytics, webscale applications and web search.other point is low power consumption and low cost.

The ARM architecture may face Jevon’s paradox which states that the resources increasing efficiency tends to increase the rate of consumption of that resource (rather than reducing the use).
The problems with ARM architecture: They support 32 bit instruction sets and most server operating softwares and applications use 64 bit architectures. Even if ARM servers are used in future, many applications would have to be rewritten for ARM architecture.
Also, data center buyers will have to get used to ARM technologies. Moreover they need to support multiple architectures to support their data centes.

TryStack is an OpenStack Essex on ARM sandbox is the only one available now. TryStack resembles the cloud environment which can be created by using OpenStack software. It allows testing of reference architectures. If we want to check how software running on ARM server against Xeon(Intel) server,TryStack is a sandbox for developers to play with.

The “ARM Zone” in TryStack is hosted by Core NAP. Core NAP is a service provider in Austin,TX. HP is contributing Redstone servers, Calxeda giving the server node cards, and Canonical is providing Ubuntu server 12.04 Linux to make ARM Zone. This hardware includes 25 server nodes with 24 disks. Also, 24 node-24 disk capacity of standby.

ARM and x86 for portable devices and clouds

In 2012 few products with Cortex-A15 came in the market. Cortex-A15 is ARM based processor.Previous ARM designs were focused on minimum power use at the expense of performance. In the contrary Cortex-A15 focus on strong performance with low power as secondary goal.

Intel also announced new low power CPUs for targeting data centers. Atom S1200 series has x86 instruction set compatibility in low power system on chip.

ARM will be continuing to do well for mobiles and portable devices. As these use their own OS and power is main factor. For laptops and notebooks, ARM might not be great option because of OS compatibility, still devices like Google’s Chromebook can use ARM.

As cloud computing is considered; there are four types of workloads that should be considered. First is traditional Windows and Linux instances where users like to run random Windows or Linux-based workloads. As with compatibility to thousands of enterprise applications, x86 is the best choice.

For Single-function, tightly-controlled workloads like databases, optimizing the hardware to deliver the best price, performance, and power usage is possible. Usage of ARM or Intel depends upon optimization of power consumption or performance goals respectively.

In cloud computing, if the service provider can not predict exact applications that will be run, so broadly compatible service based on x86 is chosen. Large web properties can optimize with tightly controlled applications. for example Facebook tightly controls what will run on the ARM processors and can port anything that they need to.

Software compatibility is the major obstacle for ARM. ARM has pretty good growth in smartphone and tablet market as no necessity of x86 compatibility. Ultimately, with growth in the portable device market, large ARM-based ecosystem will be formed that could challenge x86 in the data center. For now this is possible for specialized applications. Talking about whole market, it does not seem possible in near future.

ARM Vs Intel

In the computer processor industry ARM and Intel are big competitors. ARM is based on RISC and Intel processors are based on CISC. As mentioned last post, ARM architecture is mainly used in smartphones and portable devices.

ARM based chips concentrate on high performance while Intel processors aim for low power devices. The processors that provide good ratio of both, will be a winner.

From last week's study, I understood that semiconductor companies buy licence from ARM and develop their own software on chip (SoC). So it's a big completion for Intel. Still many believe that x86 architecture is so mature that it will survive through the competition. My next study will be microarchitecture that makes difference in ARM and Intel processors.

ARM architecture

ARM architecture has RISC based computer processors. Now a days, in majority of smartphones, televisions and mobile controllers chips based on ARM architecture are used. Benefits of RISC like low cost, less heat and low power usage provides main use to portable devices. Semiconductor companies buy license for ARM architecture to design their own system.

In ARM architecture, to compensate for the simpler design, compared with processors like the Intel 80286 and Motorola 68020, some additional design features were used in addition to RISC features. These features are conditional execution, link register, powerful index addressing mode and PC-relative addressing. “Thumb instruction set” improves compiled code density and has 16 bit instructions. “Thumb-2” has 32 bit instructions and can provide variable length instruction set.

RISC and CISC (continued...)

Advantages of RISC over CISC are their speed, smaller chip designs, less cost and can be designed more quickly.

Despite of RISC advantages, RISC was not adapted as processor developers were unable to manufacture RISC chips in large enough volumes to make their price competitive. Also, Intel is a big company using CISC chips. Intel spends lots of money for chip development and research.

I came across Intel’s white paper “Migration from UNIX/RISC and Mainframe to Intel-based Solutions”. They claim that many companies have benefited by migrating to Intel processor in terms of flexibility, lower costs and reliability. I need to find out is it necessary or rather is it really beneficial?