MIPS也是蛮拼的，但真有机会逆袭ARM吗？

作者：吉田顺子 电子产业真的了解有关MIPS的一切重要细节吗？大多数产业分析师的答案可能是肯定的。也许的确是这样没错。 MIPS处理器核心架构及其高功效性能，一直是百听不厌的MIPS传奇中一个重要的部分。然而，在移动领域中，MIPS在与ARM的竞争中一直处于不利地 位，如今大家都认为MIPS的大势已去，业界观察家们对于MIPS的热情也快要消失殆尽了。 在新兴的可穿戴设备市场或是更 加成熟的网络与家庭娱乐领域，MIPS还占有一定的市场地位。但在目前的全球市场上，MIPS已经不再是移动世界的参与者了，因为几乎没有一颗智能手机 的应用处理器(AP)采用MIPS架构。事实上，MIPS甚至连要说是‘败犬’的机会都没有。 对于MIPS的新主人──Imagination Technologies来说，想改变这个现状都已经很困难了，更别说要反转这一趋势了。 但这并不表示Imagination公司连尝试的机会都没有。 Imagination公司最近同时发表了两份完整的简报，介绍该公司如何实现“跨多个市场的SoC创新”，以及宣传“移动SoC中的创新”。 大多数的业界分析师并未在另一份PPT简报中看到什么新的东西。Linley Group公司首席分析师Linley Gwennap就直接表示，“Imagination公司真正需要的是发布一些新的MIPS客户，以便展示一些市场动能。” 确实如此，但Imagination的这些简报却有助于让我们更清楚地了解这家公司的策略以及有关MIPS CPU的一些新特性。 IP与IP模块 ARM和Imagination这两家公司都提供了CPU和GPU产品。那么Imagination公司的产品究竟有什么不同呢？Imagination公司表示，主要区别在于两家公司提供的IP模块广度。 除了CPU和GPU核心以外，Imagination公司还提供了种类广泛的IP，从硬线视频编码器/译码器模块(PowerVR视频处理单元)和针对Wi-Fi的Ensigma射频处理单元到蓝牙、数字与模拟电视/收音机模块。 Imagination的其它IP还包括影像信号处理(PowerVR ISP)、安全模块(Ensigma网络处理单元)和音频引擎(MIPS MCU)。 然而，ARM目前还没有类似于Imagination Ensigma的射频处理IP。 Imagination认为，透过提供更多的IP模块将使其具备比竞争对手更强大的优势，理论上来说，也能让芯片供应商更易于采购到所需要的东西，以及开发出自家的SoC。 重点是Imagination公司并不是只推MIPS CPU和PowerVR GPU。移动市场也不是Imagination公司追求的唯一市场。该公司还着眼于其它目标市场，包括可穿戴式和物联网(IoT)设备、家庭娱乐、路由器、家庭/企业网络以及汽车。 如同Tirias Research公司创始人兼总分析师Jim McGregor所说的，“Imagination公司确实想借助任何或所有公司的IP，以利于在这些市场中赢得机会。” 在此背景下，Imagination公司在推动MIPS CPU方面采取了长期的策略。 Imagination 公司还鼓励各种不同的业务模式，一些芯片供应商可以只授权个别IP模块，或自由选择子系统IP。供应商还可以使用Imagination公司的平台产品。 有些公司甚至要求Imagination公司开发完整的SoC。在这种情况下Imagination公司透过另外的方式完成这项任务，并提交网表给客户。 本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：MIPS的性能与功耗 {pagination} MIPS的性能与功耗 从高端处理器(如MIPS P5600)到中阶CPU(如MIPS InterAptive CPU) 和微控制器CPU(如MIPS M51)，当各种CPU与竞争对手的同级产品进行比较时，Imagination公司宣称每个MIPS核心都具有更高的CoreMark/MHz得分。 (根据Imagination表示，这些比较都是「各方面一一对应」的同性质产品比较，例如二者采用相同的制程节点、相同的L1/L快取存等等)。

图1：MIPS CPU展现先进的性能效率。
Source：Imagination Technologies3Ffesmc

从图1可以看出，相同频率的MIPS P5600与ARM应用处理器CPU之间的性能大约有10%的差别。MIPS在单位功耗性能(CoreMark/mW)和单位面积性能(CoreMark/mm2)方面更胜一筹，Imagination公司表示。 就拿用于移动市场中高端应用处理器的MIPS P5600 CPU来说，它的CoreMark/mW值至少比竞争对手的低50%，因此Imagination公司有充分理由认为MIPS具有更低功耗的性能优势。 Imagination公司发言人表示，“最重要的是你不需要超频CPU，就能在同样的频率下取得相同的性能。”

图2：MIPS CPU——领先的每mW高端性能。
Source：Imagination Technologies3Ffesmc

至于CPU面积(如图3)，据Imagination公司透露，MIPS P5600系列CPU所用的面积比竞争对手的系列CPU小30%。

图3：MIPS CPU——领先的每平方毫米高端性能。
Source：Imagination Technologies3Ffesmc

本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：热调节相比竞争对手的GPU有优势 {pagination} 热调节 当一款芯片(CPU、GPU或SoC)达到温度极限时，它会透过降低频率的方式来降低热量和温度。透过使用大家在计算机架构中熟知的“CPU节流”技术，移动设备可自动调整微处理器的工作频率，以便节省能耗，或减少芯片产生的热量。 根 据最近发布的GFXBench 3.0(如图4)显示，即使在第30次运行时，PowerVR GPU(包括PowerVR SGX GPU和PowerVR Rogue GPU)仍能维持高水平的性能。此时相当于智能手机使用者连续15至20分钟在移动设备上执行绘图密集应用(如游戏或导航)。

图4：PowerVR GPU——领先的性能效率
Source：Imagination Technologies3Ffesmc

相反地，竞争对手的GPU在执行一段时间后会变得太热，迫使性能降低20%至30%。在所有的像素绘制以及渲染过后，仍能维持连续稳定的性能非常重要。这正是高功效架构发挥作用的时候。 本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：为移动市场开发IP {pagination} 为移动市场开发IP 坦白说，当今电子产业中的许多公司并不看好MIPS处理器在全球移动市场的生存机会，因为在过去十年来，ARM公司已经在这个市场建立起强大的生态系统了。 总之，Linley Group公司资深分析师Mike Demler表示，“要想藉由撼动CPU市场，进而改变移动市场的发展方向，Imagination的机会并不大。” 但这并不意味着Imagination公司在移动市场中就没有机会了。在图5中，Imagination详细介绍该公司种类广泛的IP如何因应各种类型的移动设备，其中包括超便宜的设备和高端的智能手机。

图5：Imagination公司的IP在智能手机和平板电脑中的应用情况。
Source：Imagination Technologies3Ffesmc

虽然目前还没有一颗基于MIPS的应用处理器可用于移动设备，但Imagination公司对于以其完整的IP产品组合吸引新的授权公司仍抱有很大的希望。 本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：MIPS在汽车中的应用 {pagination} MIPS在汽车中的应用 尽管如此，Imagination公司则看好其IP模块在汽车市场中的潜在机会。Imagination公司的IP积极瞄准汽车市场的多元应用，从传感器/ 连接性到安全关键应用、信息娱乐系统和导航平台等各方面。截至目前为止，瑞萨电子(Renesas Electronics)和德州仪器(TI)是在其车载信息娱乐系统芯片中使用Imagination公司PowerVR GPU的两家大公司。但这种应用如何扩展到其它车载设备目前仍是未知数。

图6：瞄准汽车市场的Imagination公司IP
Source：Imagination Technologies3Ffesmc

本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：MIPS在可穿戴设备的应用 {pagination} MIPS在可穿戴设备的应用 即使最乐观看待MIPS在移动市场机会的产业分析师们，更希望MIPS着眼于可穿戴设备市场的表现。 Linley Group公司首席分析师Linley Gwennap表示，“Imagination公司提供的IP组合，特别是其中搭载ARM公司所缺少的蓝牙模块，非常适合可穿戴设备需求的……对于这些可 穿戴设备与许多数字家庭设备(如机顶盒、蓝光播放器)来说，应用本身并不是很重要，因为这些设备通常会与所有的软件一起搭售。” Imagination公司积极地为物联网设备供应商搭建基础架构。今年早些时候，该公司推出了一款应用独立型平台──FlowCloud，它能快速构建和管理机器到机器(M2M)以及人到机器(HMI)的连网服务。

图7：FlowCloud架构。
Source：Imagination Technologies3Ffesmc

那些从未搭建过物联网或云端连网设备的公司应该能够从FlowCloud技术获得很大的帮助，Imagination公司指出。FlowCloud服务包括注册、认证、关联、安全提示、更新以及报告控制。 在开发物联网设备方面，Imagination公司携手合作伙伴，创建了多款完全支持FlowCloud的参考平台，例如来自Digilent公司的 chipKIT Wi-Fire开发平台就使用了带MIPS microAptiv CPU的PIC32微控制器，而且据称有板载Wi-Fi。

图8：chipKIT WiFi开发板。
Source：Imagination Technologies3Ffesmc

本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：MIPS的生态系统 {pagination} MIPS的生态系统 对于MIPS背后的市场动能持怀疑论的人认为，MIPS的周围缺少“生态系统”。 Ririas Research公司创始人兼首席分析师Jim McGregor指出，“MIPS面临的最艰巨的挑战在于如何战胜围绕其它架构建立起来的生态系统，特别是ARM。” 但在结合MIPS CPU和PowerVR GPU后，Imagination公司的确拥有很大的生态系统，其中包括了工具、中间件、软件和应用程序。只不过在提到移动CPU的生态系统时，就另当别论了。 McGregor质疑，“你如何战胜一个由于在最重要的平台——移动设备上取得了巨大成功而今得以掌控技术方向的生态系统？从服务器供应商到嵌入式应用的每一家厂商现在都想充分利用移动生态系统的成功和广度更上一层楼，而这个生态系统目前正是围绕着ARM所建立的。”

图9：Imagination从众多市场的SoC中寻找IP的应用场合。
Source：Imagination Technologies3Ffesmc

Imagination最近明确表示，该公司已在许多领域取得极具竞争力的IP产品，而将MIPS应用于移动设备并非当务之急。对于Imagination公司来说，从移动领域以外的广泛产品应用中赢得最多的应用市场更加重要。 但说到底，正如McGregor所指出的，“对于Imagination公司真正有帮助的消息，当然是一些成功的案例了。” 本文授权编译自EE Times，版权所有，谢绝转载 参考英文原文：Why MIPS? Imagination Makes Its Case，by Junko Yoshida {pagination} Why MIPS? Imagination Makes Its Case Junko Yoshida Does the industry know everything it needs to know about MIPS? Most industry analysts think they do. And they’re probably right. MIPS processor cores’ architecture and its power-efficient performance are an integral part of the well told MIPS legacy. Industry observers’ enthusiasm for MIPS tends to be muted, if not non-existent, largely because the world has already decided that MIPS has lost the mobile battle against ARM. MIPS’s market position might still prove to be different in the nascent wearable device market, or in more established networking and home entertainment segments. But at a time when there is not a single MIPS-based application processor designed for smartphones on the global market, MIPS is a non-player in the mobile world. Realistically, it isn’t even an “underdog.” For Imagination Technologies, the new owner of MIPS, to change the narrative is hard, and to reverse the momentum is even harder. But that’s not to say that the company shouldn’t be trying. Imagination recently put together two sets of comprehensive presentations -- one illustrating how Imagination is enabling “innovation in SoCs across many markets,” and another on “innovation in mobile SoCs.” Most industry analysts I contacted find no news in just another PowerPoint presentation. Linley Gwennap, principle analyst of The Linley Group, was blunt: “What Imagination really needs is to announce some new MIPS customers -- to show some market momentum.” Well put. It’s hard to argue with Gwennap, but the Imagination presentations offered me a broader view of the company’s strategy and a few new nuggets about MIPS CPUs. At the risk of repeating what you might already know about MIPS/Imagination, here are a few facts about where MIPS stands, and some clues to the big picture Imagination hopes to paint for its new customers, if there are any. We sum them up in the following eight pages. IP and IP blocks Both ARM and Imagination offer CPUs and GPUs. What difference does Imagination bring to the table? The distinction lies in the breadth of IP blocks the two companies offer, according to Imagination. Beyond CPU and GPU cores, Imagination now offers a variety of IPs ranging from hardwired video encoder/decoder blocks (PowerVR video processing unit) and an Ensigma radio processing unit for WiFi to Bluetooth, digital, and analog TV/radio. Imagination's other IPs include image signal processing (PowerVR ISP), a security block (Ensigma network processing unit), and an audio engine (MIPS MCU). Currently, ARM offers no IPs for radio processing equivalent to Imagination's Ensigma. Imagination believes it has an edge over its competitor by offering more IP blocks that, in theory, make it easy for chip vendors to shop for what they need and develop their own SoCs. The point here is that Imagination isn't in the business of just pushing MIPS CPUs and PowerVR GPUs. Mobile isn't the only market Imagination is after, either. Other target markets include wearable and IoT devices, home entertainment, routers, home/enterprise networking, and automotive. As Jim McGregor, founder and principal analyst at Tirias Research, told us, "Imagination is and wants to use any or all of its IP to win opportunities in these markets." Against that backdrop, Imagination takes a long view in promoting MIPS CPUs. The company also encourages a variety of business models, under which some chip vendors might just license individual IP blocks or opt for subsystem IPs. Vendors can take Imagination's platform offering. Some companies even ask Imagination to develop a complete SoC, in which case Imagination, through another outfit, does the job and gives a net list to its customer. Next page: MIPS performance (CoreMark/MHz) MIPS performance (CoreMark/MHz) From a high-end processor like MIPS P5600 to a mid-range CPU such as MIPS InterAptive CPU and a microcontroller CPU like MIPS M51, Imagination boasts that each MIPS core consistently scores higher CoreMark/MHz across the board, when each CPU is compared to its competitors' equivalent offerings. (These are "apple-to-apple" comparisons, according to Imagination, as it compares each at the same process node, the same L1/L2 cache, etc.) Click here for larger image (Source: Imagination Technologies) As you can see in the bar graph above, the difference in performance is about 10 percent at the same frequency between MIPS's P5600 vs. ARM's apps processor CPU. Where MIPS sets itself apart further is in its performance in power consumption (CoreMark/mW) and area (CoreMark/mm2), according to Imagination. Next page: MIPS power (CoreMark/mW) and area (CoreMark/mm2) MIPS power (CoreMark/mW) and area (CoreMark/mm2) Take the example of MIPS P5600 CPU intended for high-end apps processors in the mobile market. MIPS P5600 CPU performance at CoreMark/mW is at least 50 percent lower than that of competitors', thus allowing Imagination to make the case for MIPS lower power performance advantage. The bottom line: "You don't need to overclock CPU -- thus running it hot -- in order to achieve the same performance at the same frequency," said an Imagination spokesman. Click here for larger image (Source: Imagination Technologies) When it comes to the CPU area (see below), a cluster of MIPS P5600 CPUs uses 30 percent less area than that of a cluster of a competitor's CPUs, according to Imagination. Click here for larger image (Source: Imagination Technologies) Next page: Thermal throttling Thermal throttling When a chip (CPU, GPU, or SoC) reaches a temperature limit, it will reduce frequency to cut heat and temperature. Using a technique known as "CPU throttling" in computer architecture, a mobile device automatically adjusts the frequency of a microprocessor either to conserve power or to reduce the amount of heat generated by the chip. Click here for larger image (Source: Imagination Technologies) The recently released GFXBench 3.0 (shown above) illustrates that PowerVR GPUs (both PowerVR SGX GPU and PowerVR Rogue GPU) continuously maintain high-level performance even in the 30th run -- which is equivalent to a smartphone user running graphics-intensive applications, such as game or navigation, on a mobile device for 15 to 20 minutes. In contrast, the competitor's GPUs get too hot after a while, forcing performance to drop 20 to 30 percent. After all the pixels are drawn and everything is rendered, maintaining continuous performance is important. That's when power-efficient architecture matters, says Imagination. Next page: Mapping out Imagination's IPs for mobile Mapping out Imagination's IPs for mobile Bluntly put, many players in the electronics industry today are not sanguine about the survival chances for MIPS processors in a global mobile market where, in the last decade, ARM has built its formidable ecosystem. In short, "There's not much [Imagination] can do to move the CPU needle in their direction for mobile," says Mike Demler, senior analyst at The Linley Group. But that doesn't mean there is no opportunity in the mobile segment for Imagination. In the following chart, Imagination maps out how a variety of IPs offered by Imagination would fit into a range of mobile devices including ultra-affordable devices and high-end smartphones. Click here for larger image Mapping out Imagination's IPs in smartphones and tablets (Source: Imagination Technologies) Although no single MIPS-based apps processors exist today for mobile devices, Imagination is hopeful for its full IP portfolio to attract new licensees. Next page: MIPS for automotive? MIPS for automotive? I'm the first to admit that I've known little about where MIPS is going on the automotive market. Nonetheless, Imagination is bullish about potential opportunities for Imagination's IP blocks in automotive. Shown below is how its IP offerings could potentially fit in automotive -- everything from sensors/connectivity to safety critical apps and infotainment and navigation platforms. Thus far, Renesas and Texas Instruments are the giants using Imagination's PowerVR GPUs for the chips in their in-vehicle infotainment clusters. How that might propagate into other parts of in-vehicle devices remains largely unknown. Click here for larger image Mapping out Imagination's IPs for automotive (Source: Imagination Technologies) Next page: MIPS in wearable devices MIPS in wearable devices Even those industry analysts most pessimistic about MIPS's chances in the mobile world are more hopeful for MIPS in the wearable device market. Why? Linley Gwennap, principle analyst of The Linley Group, tells us, "The combination of IP that Imagination offers, particularly with the Bluetooth block that ARM lacks, is well suited to wearable devices... For these wearables as well as for many digital-home (e.g., set-top box, Blu-ray) devices, apps are not important because the device generally ships with all of its software." Imagination has been proactive in building an enabling infrastructure for IoT device vendors. Earlier this year, the company rolled out an application-independent platform called FlowCloud, designed to enable fast construction and management of machine-to-machine and man-to-machine connected services. Click here for larger image (Source: Imagination Technologies) Those who have never built IoT or cloud-connected devices should be able to get help from FlowCloud technology, according to Imagination. FlowCloud services include registration, authentication, association, security notification, updates, and report control. As for developing IoT devices, Imagination's partners have created several reference platforms with full support for FlowCloud. For one, the chipKIT Wi-Fire development platform from Digilent uses a PIC32 microcontroller (MCU) with a MIPS microAptiv CPU and boasts on-board WiFi. (Source: Imagination Technologies) Next page: Proverbial ecosystem Proverbial ecosystem Doubters about the market momentum behind MIPS tend to point out the lack of "ecosystem" around MIPS. As Jim McGregor, founder and principal analyst at Tirias Research, notes, "The most difficult challenge MIPS faces is overcoming the momentum and build-out of the ecosystem around other architectures, particularly ARM." Imagination, when both MIPS CPUs and PowerVR GPUs are combined, does offer a pretty big ecosystem that includes tools, middleware, software, and apps. But when it comes to the ecosystem for CPUs in mobile, the story is different. Says McGregor: "How do you overcome an ecosystem that is now driving the direction of technology all because of its success in the most important platforms -- mobile devices? Everyone from server vendors to embedded applications is now looking to leverage the success and breadth of the mobile ecosystem, and that is all built around ARM at this point." Click here for larger image Imagination is in search of IP sockets in SoCs across many markets. (Source: Imagination Technologies) Imagination's latest presentations have assured us that the company does have very competitive IP in a number of areas. Imagination also makes it clear that plugging MIPS into a mobile socket isn't the most important thing for Imagination. More important is for Imagination to win as many sockets as possible in a wide variety of product applications -- beyond mobile. But in the end, as McGregor points out (and many others agree), "What would help Imagination's messaging is some success stories."