作者：吉田順子 電子產業(yè)真的了解有關MIPS的一切重要細節(jié)嗎？大多數(shù)產業(yè)分析師的答案可能是肯定的。也許的確是這樣沒錯。 MIPS處理器核心架構及其高功效性能，一直是百聽不厭的MIPS傳奇中一個重要的部分。然而，在移動領域中，MIPS在與ARM的競爭中一直處于不利地 位，如今大家都認為MIPS的大勢已去，業(yè)界觀察家們對于MIPS的熱情也快要消失殆盡了。 在新興的可穿戴設備市場或是更 加成熟的網(wǎng)絡與家庭娛樂領域，MIPS還占有一定的市場地位。但在目前的全球市場上，MIPS已經不再是移動世界的參與者了，因為幾乎沒有一顆智能手機 的應用處理器(AP)采用MIPS架構。事實上，MIPS甚至連要說是‘敗犬’的機會都沒有。 對于MIPS的新主人──Imagination Technologies來說，想改變這個現(xiàn)狀都已經很困難了，更別說要反轉這一趨勢了。 但這并不表示Imagination公司連嘗試的機會都沒有。 Imagination公司最近同時發(fā)表了兩份完整的簡報，介紹該公司如何實現(xiàn)“跨多個市場的SoC創(chuàng)新”，以及宣傳“移動SoC中的創(chuàng)新”。 大多數(shù)的業(yè)界分析師并未在另一份PPT簡報中看到什么新的東西。Linley Group公司首席分析師Linley Gwennap就直接表示，“Imagination公司真正需要的是發(fā)布一些新的MIPS客戶，以便展示一些市場動能?！? 確實如此，但Imagination的這些簡報卻有助于讓我們更清楚地了解這家公司的策略以及有關MIPS CPU的一些新特性。 IP與IP模塊 ARM和Imagination這兩家公司都提供了CPU和GPU產品。那么Imagination公司的產品究竟有什么不同呢？Imagination公司表示，主要區(qū)別在于兩家公司提供的IP模塊廣度。 除了CPU和GPU核心以外，Imagination公司還提供了種類廣泛的IP，從硬線視頻編碼器/譯碼器模塊(PowerVR視頻處理單元)和針對Wi-Fi的Ensigma射頻處理單元到藍牙、數(shù)字與模擬電視/收音機模塊。 Imagination的其它IP還包括影像信號處理(PowerVR ISP)、安全模塊(Ensigma網(wǎng)絡處理單元)和音頻引擎(MIPS MCU)。 然而，ARM目前還沒有類似于Imagination Ensigma的射頻處理IP。 Imagination認為，透過提供更多的IP模塊將使其具備比競爭對手更強大的優(yōu)勢，理論上來說，也能讓芯片供應商更易于采購到所需要的東西，以及開發(fā)出自家的SoC。 重點是Imagination公司并不是只推MIPS CPU和PowerVR GPU。移動市場也不是Imagination公司追求的唯一市場。該公司還著眼于其它目標市場，包括可穿戴式和物聯(lián)網(wǎng)(IoT)設備、家庭娛樂、路由器、家庭/企業(yè)網(wǎng)絡以及汽車。 如同Tirias Research公司創(chuàng)始人兼總分析師Jim McGregor所說的，“Imagination公司確實想借助任何或所有公司的IP，以利于在這些市場中贏得機會。” 在此背景下，Imagination公司在推動MIPS CPU方面采取了長期的策略。 Imagination 公司還鼓勵各種不同的業(yè)務模式，一些芯片供應商可以只授權個別IP模塊，或自由選擇子系統(tǒng)IP。供應商還可以使用Imagination公司的平臺產品。 有些公司甚至要求Imagination公司開發(fā)完整的SoC。在這種情況下Imagination公司透過另外的方式完成這項任務，并提交網(wǎng)表給客戶。 本文授權編譯自EE Times，版權所有，謝絕轉載 本文下一頁：MIPS的性能與功耗 {pagination} MIPS的性能與功耗 從高端處理器(如MIPS P5600)到中階CPU(如MIPS InterAptive CPU) 和微控制器CPU(如MIPS M51)，當各種CPU與競爭對手的同級產品進行比較時，Imagination公司宣稱每個MIPS核心都具有更高的CoreMark/MHz得分。 (根據(jù)Imagination表示，這些比較都是「各方面一一對應」的同性質產品比較，例如二者采用相同的制程節(jié)點、相同的L1/L快取存等等)。

圖1：MIPS CPU展現(xiàn)先進的性能效率。
Source：Imagination TechnologiesYDJesmc

從圖1可以看出，相同頻率的MIPS P5600與ARM應用處理器CPU之間的性能大約有10%的差別。MIPS在單位功耗性能(CoreMark/mW)和單位面積性能(CoreMark/mm2)方面更勝一籌，Imagination公司表示。 就拿用于移動市場中高端應用處理器的MIPS P5600 CPU來說，它的CoreMark/mW值至少比競爭對手的低50%，因此Imagination公司有充分理由認為MIPS具有更低功耗的性能優(yōu)勢。 Imagination公司發(fā)言人表示，“最重要的是你不需要超頻CPU，就能在同樣的頻率下取得相同的性能?！?

圖2：MIPS CPU——領先的每mW高端性能。
Source：Imagination TechnologiesYDJesmc

至于CPU面積(如圖3)，據(jù)Imagination公司透露，MIPS P5600系列CPU所用的面積比競爭對手的系列CPU小30%。

圖3：MIPS CPU——領先的每平方毫米高端性能。
Source：Imagination TechnologiesYDJesmc

本文授權編譯自EE Times，版權所有，謝絕轉載 本文下一頁：熱調節(jié)相比競爭對手的GPU有優(yōu)勢 {pagination} 熱調節(jié) 當一款芯片(CPU、GPU或SoC)達到溫度極限時，它會透過降低頻率的方式來降低熱量和溫度。透過使用大家在計算機架構中熟知的“CPU節(jié)流”技術，移動設備可自動調整微處理器的工作頻率，以便節(jié)省能耗，或減少芯片產生的熱量。 根 據(jù)最近發(fā)布的GFXBench 3.0(如圖4)顯示，即使在第30次運行時，PowerVR GPU(包括PowerVR SGX GPU和PowerVR Rogue GPU)仍能維持高水平的性能。此時相當于智能手機使用者連續(xù)15至20分鐘在移動設備上執(zhí)行繪圖密集應用(如游戲或導航)。

圖4：PowerVR GPU——領先的性能效率
Source：Imagination TechnologiesYDJesmc

相反地，競爭對手的GPU在執(zhí)行一段時間后會變得太熱，迫使性能降低20%至30%。在所有的像素繪制以及渲染過后，仍能維持連續(xù)穩(wěn)定的性能非常重要。這正是高功效架構發(fā)揮作用的時候。 本文授權編譯自EE Times，版權所有，謝絕轉載 本文下一頁：為移動市場開發(fā)IP {pagination} 為移動市場開發(fā)IP 坦白說，當今電子產業(yè)中的許多公司并不看好MIPS處理器在全球移動市場的生存機會，因為在過去十年來，ARM公司已經在這個市場建立起強大的生態(tài)系統(tǒng)了。 總之，Linley Group公司資深分析師Mike Demler表示，“要想藉由撼動CPU市場，進而改變移動市場的發(fā)展方向，Imagination的機會并不大?！? 但這并不意味著Imagination公司在移動市場中就沒有機會了。在圖5中，Imagination詳細介紹該公司種類廣泛的IP如何因應各種類型的移動設備，其中包括超便宜的設備和高端的智能手機。

圖5：Imagination公司的IP在智能手機和平板電腦中的應用情況。
Source：Imagination TechnologiesYDJesmc

雖然目前還沒有一顆基于MIPS的應用處理器可用于移動設備，但Imagination公司對于以其完整的IP產品組合吸引新的授權公司仍抱有很大的希望。 本文授權編譯自EE Times，版權所有，謝絕轉載 本文下一頁：MIPS在汽車中的應用 {pagination} MIPS在汽車中的應用 盡管如此，Imagination公司則看好其IP模塊在汽車市場中的潛在機會。Imagination公司的IP積極瞄準汽車市場的多元應用，從傳感器/ 連接性到安全關鍵應用、信息娛樂系統(tǒng)和導航平臺等各方面。截至目前為止，瑞薩電子(Renesas Electronics)和德州儀器(TI)是在其車載信息娛樂系統(tǒng)芯片中使用Imagination公司PowerVR GPU的兩家大公司。但這種應用如何擴展到其它車載設備目前仍是未知數(shù)。

圖6：瞄準汽車市場的Imagination公司IP
Source：Imagination TechnologiesYDJesmc

本文授權編譯自EE Times，版權所有，謝絕轉載 本文下一頁：MIPS在可穿戴設備的應用 {pagination} MIPS在可穿戴設備的應用 即使最樂觀看待MIPS在移動市場機會的產業(yè)分析師們，更希望MIPS著眼于可穿戴設備市場的表現(xiàn)。 Linley Group公司首席分析師Linley Gwennap表示，“Imagination公司提供的IP組合，特別是其中搭載ARM公司所缺少的藍牙模塊，非常適合可穿戴設備需求的……對于這些可 穿戴設備與許多數(shù)字家庭設備(如機頂盒、藍光播放器)來說，應用本身并不是很重要，因為這些設備通常會與所有的軟件一起搭售?！? Imagination公司積極地為物聯(lián)網(wǎng)設備供應商搭建基礎架構。今年早些時候，該公司推出了一款應用獨立型平臺──FlowCloud，它能快速構建和管理機器到機器(M2M)以及人到機器(HMI)的連網(wǎng)服務。

圖7：FlowCloud架構。
Source：Imagination TechnologiesYDJesmc

那些從未搭建過物聯(lián)網(wǎng)或云端連網(wǎng)設備的公司應該能夠從FlowCloud技術獲得很大的幫助，Imagination公司指出。FlowCloud服務包括注冊、認證、關聯(lián)、安全提示、更新以及報告控制。 在開發(fā)物聯(lián)網(wǎng)設備方面，Imagination公司攜手合作伙伴，創(chuàng)建了多款完全支持FlowCloud的參考平臺，例如來自Digilent公司的 chipKIT Wi-Fire開發(fā)平臺就使用了帶MIPS microAptiv CPU的PIC32微控制器，而且據(jù)稱有板載Wi-Fi。

圖8：chipKIT WiFi開發(fā)板。
Source：Imagination TechnologiesYDJesmc

本文授權編譯自EE Times，版權所有，謝絕轉載 本文下一頁：MIPS的生態(tài)系統(tǒng) {pagination} MIPS的生態(tài)系統(tǒng) 對于MIPS背后的市場動能持懷疑論的人認為，MIPS的周圍缺少“生態(tài)系統(tǒng)”。 Ririas Research公司創(chuàng)始人兼首席分析師Jim McGregor指出，“MIPS面臨的最艱巨的挑戰(zhàn)在于如何戰(zhàn)勝圍繞其它架構建立起來的生態(tài)系統(tǒng)，特別是ARM?！? 但在結合MIPS CPU和PowerVR GPU后，Imagination公司的確擁有很大的生態(tài)系統(tǒng)，其中包括了工具、中間件、軟件和應用程序。只不過在提到移動CPU的生態(tài)系統(tǒng)時，就另當別論了。 McGregor質疑，“你如何戰(zhàn)勝一個由于在最重要的平臺——移動設備上取得了巨大成功而今得以掌控技術方向的生態(tài)系統(tǒng)？從服務器供應商到嵌入式應用的每一家廠商現(xiàn)在都想充分利用移動生態(tài)系統(tǒng)的成功和廣度更上一層樓，而這個生態(tài)系統(tǒng)目前正是圍繞著ARM所建立的?！?

圖9：Imagination從眾多市場的SoC中尋找IP的應用場合。
Source：Imagination TechnologiesYDJesmc

Imagination最近明確表示，該公司已在許多領域取得極具競爭力的IP產品，而將MIPS應用于移動設備并非當務之急。對于Imagination公司來說，從移動領域以外的廣泛產品應用中贏得最多的應用市場更加重要。 但說到底，正如McGregor所指出的，“對于Imagination公司真正有幫助的消息，當然是一些成功的案例了?！? 本文授權編譯自EE Times，版權所有，謝絕轉載 參考英文原文：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."