在過去幾年來,包括智能手機與平板計算機在內(nèi)的移動設(shè)備越來越受到市場歡迎,卻也被淪為技術(shù)指針差距(specmanship)下的犧牲品;不論那些設(shè)備的屏幕尺寸(以及影像處理器可支持的像素數(shù)字),今日大多數(shù)的移動設(shè)備價值顯然是由所搭載的處理器性能來評量──例如處理器跑多快,以及最重要的,有幾個核心。
處理器核心數(shù)量特別是一種受歡迎的量測指針──對新聞媒體與應(yīng)用處理器供貨商的銷售部門來說都是──可用以描述下一代平板設(shè)備或智能手機的科技進展;才開始不久(從2012年初)的雙核心應(yīng)用處理器大戰(zhàn),很快地被新興的四核心(quad-core)處理器取代。但現(xiàn)在,你也可以把四核心拋在后面了,因為八核心(octa-core)處理器正要掀起風潮。
這種多核心大賽很妙,會讓人一直覺得“不夠”──特別是如果你發(fā)現(xiàn)今年買的新手機/平板沒有配備至少八核心的處理器時…有人在說十六核心嗎?
據(jù)了解,三星(Samsung) 的 Galaxy S4 應(yīng)該是首款搭載八核心處理器的智能手機,該系列有部分型號是采用高通(Qualcomm)的四核心處理器,有部份則是內(nèi)建三星自家的八核心Exynos 5處理器;但連三星的共同CEO申宗均(JK Shin)在接受媒體訪問時都表示,無論采用的是那一種處理器,其實一般大眾的使用體驗都是相同的。
所以申宗鈞的意思是說,消費者不會在乎手機是使用四核心還是八核心處理器嗎?我懷疑他的重點其實是在于確保應(yīng)用處理器的多供應(yīng)來源,但這位三星高層主管卻不小心說出了產(chǎn)業(yè)界過度吹捧多核心處理器的現(xiàn)實。
要評斷應(yīng)用處理器在現(xiàn)實世界運作效能,處理器核心的數(shù)量是一種稍嫌太過簡單的指針;重要的是在智能手機或是平板設(shè)備上執(zhí)行特定移動應(yīng)用程序時每個核心的最佳化,以及───更重要的──基于節(jié)省能源的考量,處理器執(zhí)行任務(wù)時的效能。
為此,臺灣芯片設(shè)計業(yè)者聯(lián)發(fā)科(MediaTek)在這場多核心處理器大戰(zhàn)中,投下一個新的漣漪──異質(zhì)多核心處理技術(shù)(heterogeneous multi-processing,HMP)。
根據(jù)業(yè)界消息,聯(lián)發(fā)科最近推出了新款采用ARM big.LITTLE 架構(gòu)的四核心SoC,鎖定平板設(shè)備市場;這款新組件不同之處就在于添加了HMP功能。三星的Exynos 5 Octa也是采用big.LITTLE架構(gòu),但聯(lián)發(fā)科與三星的配置不相同。
Exynos 5 Octa采用三星稱為叢集遷移(cluster migration)的配置──處理器的遷移模式是將任務(wù)在核心的叢集之間移動;當運作于超越四核心A7能力的高性能水準時,調(diào)度程序 (scheduler)會將之關(guān)閉,將所有任務(wù)轉(zhuǎn)移至A15核心。而聯(lián)發(fā)科采用的HMP方案,則是能將個別執(zhí)行緒分派至最佳的核心,以保證更好的處理效果。
本文授權(quán)編譯自EE Times,版權(quán)所有,謝絕轉(zhuǎn)載
本文下一頁:聯(lián)發(fā)科已經(jīng)率先點燃了戰(zhàn)火
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Gartner分析師Mark Hung表示:“三星的案例是讓big核心或LITTLE核心運作,兩者不同時;”至于聯(lián)發(fā)科的案例則是一個、兩個、三個或全部四個核心都會同時運作。Linley Group的資深分析師Mike Demler更進一步解釋:
“雖有聯(lián)發(fā)科的HMP技術(shù),操作系統(tǒng)還是將中央處理器視為四核心,但能將某項任務(wù)指派(或轉(zhuǎn)移)給任何一個獨立處理器核心;A15與A7核心會同時運作,而任務(wù)仍能在兩者之間轉(zhuǎn)移,以達到功率-性能的最佳化?!?
聯(lián) 發(fā)科最新發(fā)布的平板設(shè)備SoC是四核心組件,不過該公司也透露,預(yù)計在今年第四季將發(fā)表八核心產(chǎn)品。而為了與競爭對手做區(qū)隔,聯(lián)發(fā)科號稱其解決方案會是 “真正的(True)八核心處理器”──也就是會納入HMP技術(shù)。根據(jù)聯(lián)發(fā)科的解釋,其八核心方案會根據(jù)每個應(yīng)用程序與任務(wù),智能分配處理能力到所需之 處;該公司近期將發(fā)表技術(shù)白皮書透露更多細節(jié)。
這種架構(gòu)明顯與采用其它多核心解決方案的負載處理系統(tǒng)不同,包括那些八核心產(chǎn)品──通常會將任務(wù)過于苛刻地限制,導(dǎo)致不佳的反應(yīng)時間或是系統(tǒng)停擺。HMP是否會成為多核心應(yīng)用處理器大戰(zhàn)的另一個關(guān)鍵因素還有待觀察;無論如何,聯(lián)發(fā)科已經(jīng)率先點燃了新火苗。
本文授權(quán)編譯自EE Times,版權(quán)所有,謝絕轉(zhuǎn)載
編譯:Judith Cheng
參考英文原文:Defining Next Frontier of Mobile Multi-Core Processing,by Junko Yoshida
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MADISON, Wis. -- Mobile devices (smartphones and tablets included) have grown more popular over the last several years, but they have also fallen victim to specmanship. Aside from a device's screen size (and the number of pixels its image processor can handle), much of the worth of a mobile device nowadays appears to be measured by which processing core the CPU uses, how fast the processor runs, and, most importantly, how many cores the apps processor has.
Core count has been a particularly popular measuring stick -- for both the breathless news media and the marketing departments of apps processor suppliers -- to illustrate technical advancements in a next-generation tablet or smartphone. The dual-core apps processor battle (still new early in 2012) was quickly replaced by the emerging quad-core devices late last year. But you can forget about quad-core processors; octa-core devices are now the rage.
The multi-core race certainly has a funny way of making you feel inadequate, especially if the new phone/tablet you buy this year isn't powered by at least eight processor cores. Do I hear 16?
Consumers won't notice the difference?
Samsung's Galaxy S4 is believed to be the first smartphone to give consumers an awesome octa-core processing experience. However, according to a CNET report in late April, US customers aren't likely to get their hands on it.
Some models of Samsung's flagship smartphone [Galaxy S4], available globally in the coming weeks, will feature a quad-core processor from Qualcomm while others will feature Samsung's Exynos 5 chip with eight cores. The U.S. version will use the 1.9GHz Qualcomm Snapdragon 600 series chip.
What caught my attention, though, is that JK Shin, co-CEO of Samsung and head of its mobile business, "told CNET after an event Wednesday in New York that the general public won't really notice or care." He also said the company chose processors that could provide a similar consumer experience.
I found that comment refreshing.
Is he really saying consumers don't care whether they get quad-core or octa-core processors? I suspect Shin's emphasis was more on the importance of securing the necessary volume of apps processors from multiple sources, but Samsung's mobile business chief might have spoken the truth inadvertently about the overblown multi-core race.
The number of processing cores is too simple a yardstick to evaluate the performance of an apps processor in real-world experience. What matters most is the optimization of each core when running certain mobile applications on smartphones or tablets and -- more importantly -- its efficiency in handling such tasks to save energy.
To that end, MediaTek is throwing a new wrinkle -- heterogeneous multi-processing (HMP) -- into the multi-core competition.
As we reported last week, the Taiwanese company is sampling a new quad-core SoC using ARM big.LITTLE architecture for the tablet market. The difference in this new quad-core SoC solution is that MediaTek is adding HMP capability to the SoC.
The Samsung Exynos 5 Octa is another SoC using the big.LITTLE architecture, but MediaTek and Samsung have implemented it differently. The Exynos 5 Octa uses what Samsung calls cluster migration -- the same technique others have used with big.LITTLE implementations. The CPU migration mode moves jobs between clusters of cores. When a high-performance operating point exceeds the capabilities of the quad A7s, the scheduler shuts them down and moves everything to the A15s.
MediaTek is adopting the HMP approach, which it says can assign individual threads to the best core, thus promising better results.
"In Samsung's case, either the big or the LITTLE cores are running, but not simultaneously," Mark Hung, wireless research vice president at Gartner, told us. In MediaTek's case, one, two, three, or all four cores may be running.
Mike Demler, senior analyst at the Linley Group, gave us this explanation for our post last week:
With MediaTek's HMP, the operating system still sees a quad-core CPU, but it can assign (or shift) a task to any CPU independently. The A15s can run at the same time as the A7s. Tasks can still be moved from one to the other for power-performance optimization.
HMP in an octa-core processor?
Just to be clear, MediaTek's newly announced tablet SoC is a quad-core device. However, the company has also joined the eight-core processor bandwagon. A spokesperson recently confirmed speculation about MediaTek's plan to launch an octa-core solution in the fourth quarter.
MediaTek is distinguishing itself from competitors (such as Samsung) by calling its solution "True Octa-Core" processing. What's so true about it? In MediaTek's opinion, it's the addition of HMP to its Octa-core solutions.
The company says on its website, "MediaTek True Octa-Core intelligently allocates processing power to where it is needed, both on a per-application and per-task basis." A white paper to be released soon (and recently obtained by EE Times) explains the process further:
This architecture reveals a significant departure from the load handling systems of other multi-core solutions – even those with eight cores -- which typically tend to restrict tasks that are too demanding, resulting in poor response times or shutdowns.
It remains to be seen whether HMP will be a defining factor in the multi-core mobile apps processor race. But by becoming the first to adopt HMP, MediaTek is banking on that premise.
責編:Quentin