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Overcoming Disk Drive Access Bottlenecks with Intel® Robson Technology
By Michael Trainor
Overview: Intel® Robson Technology Offers Extended Cache Capability
Robson is the code name for a new Intel® platform technology that uses non-volatile memory (Flash memory) to increase system responsiveness, make multi-tasking faster, and extend battery life. Robson technology will be available on Intel’s forthcoming Santa Rosa platform—the next-generation mobile platform building on the power savings and performance benefits of Intel® Centrino® processor technology. Robson technology is designed to support two new features of the upcoming Microsoft Vista* operating system: ReadyBoost* and ReadyDrive* technologies.
Early testing in Intel’s labs shows that Robson technology on a Santa Rosa platform1 running Microsoft Vista (pre-production hardware and software) improves multitasking performance with 2x improvement in application load and run time as well as a 2x improvement in resume time from hibernation over systems without Robson. Robson technology also offers increased power savings—extending battery life by an estimated 20 minutes in lab testing. And perhaps best of all, these benefits may improve as the software and hardware are tuned for production release.
Systems with Santa Rosa and Robson technology are expected to launch in the first half of 2007.
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Robson dramatically reduces the impact of mechanical hard disk drive (HDD) latency by allowing the majority of application workloads to be written and read from cache instead of slower HDDs.
—Rick Coulson, Intel Fellow, Storage Technology Group
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Hard Disk Drive Limitations Hinder Performance
The pace of technological development is often uneven. Where one technological advance rapidly evolves, others frequently lag, as illustrated in the difference between processor and hard disk drive (HDD) performance. Over the last 10 years, processor performance has improved over 30 times, but average HDD performance has only increased 1.3 times in the same period of time. This uneven development of complementary technologies has resulted in the mechanical limitations of HDDs having an enormous impact on how systems scale and take advantage of processing power.
Over the past 10 years, there have been significant improvements in HDD system interface speeds—now available at up to 3.0 GB/s with SATA—and these speeds allow large files stored on sequential sectors on the hard drive platters to be transferred very quickly. However, the vast majority of real-world HDD data transfers is actually relatively small and tends to be scattered all over the HDD platters. Getting these small bits of data off the HDD and up to the system is limited by the time required for the HDD platter to spin to the right position and the read head to move over that position. Testing has shown that these mechanical latencies make up approximately 95 percent of the time required to read small files in real-world situations. For example, Intel testing has shown that within a small transfer requiring 5.4 milliseconds, about 5.13 milliseconds are consumed by mechanical latency. Essentially, systems are forced to wait for HDDs to catch up to processor performance.
Additionally, all the mechanical work required to find the requested small files on HDDs is a major source of power drain, particularly when multitasking.
The forthcoming introduction of Intel® Robson technology is poised to eliminate many of the bottlenecks associated with HDD latency. By enabling the majority of application workload to be written and read from a system cache instead of the HDD, Robson will offer users of mobile computers built on the Santa Rosa platform significantly increased performance—particularly in application load and run time, the speed in which systems resume operation after hibernation or boot, and in system-level power usage.
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Designed to give users better overall performance and graphics, improved wireless connectivity, and improved security and manageability while lowering platform power usage, Santa Rosa will use Intel’s next-generation dual-core mobile microprocessor based on the Intel® Core™ microarchitecture. |
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Robson Shows Dramatic Improvement in Performance
The Robson memory storage subsystem plugs the performance gap between processor and HDD by acting as new layer of cache in the system memory/storage hierarchy. Robson technology, working with Microsoft Vista’s ReadyDrive* and ReadyBoost* technologies, dramatically reduces the number of times a system needs to burn power and waste time finding small bits of data scattered across the HDD. And by enabling the system to store boot and resume information in cache, Robson nearly doubles the speed at which systems boot or resume activity from hibernation mode to responsiveness (Table 1).
Simple Test System
Performance Results |
Without
Robson |
With
Robson |
| Elapsed time |
24.5 sec |
12.4 sec |
| Disk busy time |
14 sec |
2.6 sec |
| Data read |
63.5 MB |
64.4 MB |
| Read busy time |
13.9 sec |
2.5 sec |
| Effective read yield |
4.6 MB/s |
25.9 MB/s |
Table 1. With Robson enabled, application load and run time is nearly halved.
These performance benefits of Robson also extend to increased battery life. Less power is consumed as the technology ensures fewer power-hungry HDD spins. Additionally, faster load and run times mean systems can idle sooner, saving overall system power. All of this adds up to an estimated additional 20 minutes of laptop battery life on systems built on the Santa Rosa platform and enabled with Robson technology.
Robson Takes Advantage of Next-Generation Microsoft Vista* Capabilities
Robson non-volatile memory technology is designed to take advantage of the performance-accelerating capabilities of the forthcoming Microsoft Vista operating system. These capabilities include:
- Microsoft Superfetch* memory management technology, which significantly reduces disk read for typical user workloads by aggressively pre-fetching disk pages.
- Microsoft ReadyBoost technology, which allows users to increase the speed of frequently used applications by using system memory devices (Robson, USB drives, SD cards, Compact Flash, etc.) as a write-through virtual memory OS page cache.
- Microsoft ReadyDrive command set used by Windows Vista to cache small HDD writes to platform non-volatile memory (either as part of the platform or as part of a disk).
Although other forms of non-volatile memory such as USB drives can be used with these features, Robson’s integrated design takes unique advantage of Vista’s performance accelerators. As an internal device, Robson eliminates the need for end user configuration. In addition, PCI Express* devices support higher bandwidths and consume less power than USB 2.0 devices.
Robson Technology Architecture
Robson technology consists of four components:
- Robson driver. This is the heart of Robson technology—the Robson driver interfaces to Microsoft Vista’s ReadyDrive and ReadyBoost technologies, interfaces to the Intel® Matrix Storage Manager driver, and provides all the control functions necessary for managing NAND flash in a caching role.
- Intel® NAND flash memory. Robson cards are powered by Intel NAND memory that offers 40 Mb/s reads and 12-15 Mb/s writes.
- Diamond Lake ASIC controller. This controller translates the system’s PCI Express signals to the Intel NAND memory and manages the retirement of Flash memory blocks as needed.
- OROM BIOS. Robson technology includes BIOS-level option ROM (OROM) code which manages NAND access before the OS and drivers load. The OROM also controls separation handling, critical to maintaining data integrity.
Santa Rosa Extends Performance and Power Benefits
Robson is one of several exciting options for Intel’s Santa Rosa mobile technology platform, available in the first half of 2007. Santa Rosa is designed to give users better overall performance and graphics, improved wireless connectivity with draft 802.11n Wi-Fi capability, and improved security and manageability while lowering platform power usage. Santa Rosa will use an improved version of the Intel® Core™2 Duo mobile microprocessor.
Summary
By reducing the system-level impact of HDD latency issues and reducing the amount of time a mobile hard drive will need to be spinning and seeking data, Intel’s Robson technology is poised to increase the responsiveness of mobile computers, allow mobile computer users to do more tasks in less time, and allow the mobile system to use less battery power.
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