DreamWeaver: architectural support for deep sleep
DreamWeaver: architectural support for deep sleep
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DOI：
10.1145/2150976.2151009
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发表时间：
2012-03
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影响因子：
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通讯作者：
David Meisner;T. Wenisch
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文献类型：
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作者：
David Meisner;T. Wenisch
许多数据中心服务表现出低平均利用率，导致低能效。虽然CPU电压和频率缩放在历史上一直是降低功耗的有效手段，但晶体管缩放趋势限制了其有效性，CPU占系统功耗的比例正在缩小。最近的研究提倡使用全系统空闲低功耗模式来对抗能量损耗，因为这种模式提供了最大的功率节省，并且响应时间有限。然而，增加每个裸片的核心的趋势正在破坏这些休眠模式的有效性，特别是对于请求并行数据中心应用，因为跨各个核心的独立空闲时段不太可能偶然对齐。我们建议DreamWeaver，架构支持，以促进多核服务器上的请求并行应用程序的深度睡眠。DreamWeaver包含两个元素：Weave Scheduling，一种调度策略，用于合并内核之间的空闲和忙碌时段，为系统范围的深度睡眠创造机会;以及Dream Processor，一种轻量级协处理器，用于监视进入的网络流量和睡眠期间暂停的工作，以确定系统何时必须唤醒。DreamWeaver基于两个关键概念：（1）在任何核心未被占用时暂停执行和睡眠，但（2）限制任何请求可能被暂停的最长时间。与以前的调度方法不同，DreamWeaver将抢占执行进入睡眠，最大限度地提高系统最有效操作点的时间。我们证明，DreamWeaver可以顺利地权衡有界的，可预测的增加，在第99百分位的响应时间，以提高节能，并严格占主导地位的节省与电压和频率缩放和基于超时的请求恢复计划。
Numerous data center services exhibit low average utilization leading to poor energy efficiency. Although CPU voltage and frequency scaling historically has been an effective means to scale down power with utilization, transistor scaling trends are limiting its effectiveness and the CPU is accounting for a shrinking fraction of system power. Recent research advocates the use of full-system idle low-power modes to combat energy losses, as such modes provide the deepest power savings with bounded response time impact. However, the trend towards increasing cores per die is undermining the effectiveness of these sleep modes, particularly for request-parallel data center applications, because the independent idle periods across individual cores are unlikely to align by happenstance. We propose DreamWeaver, architectural support to facilitate deep sleep for request-parallel applications on multicore servers. DreamWeaver comprises two elements: Weave Scheduling, a scheduling policy to coalesce idle and busy periods across cores to create opportunities for system-wide deep sleep; and the Dream Processor, a light-weight co-processor that monitors incoming network traffic and suspended work during sleep to determine when the system must wake. DreamWeaver is based on two key concepts: (1) stall execution and sleep anytime any core is unoccupied, but (2) constrain the maximum time any request may be stalled. Unlike prior scheduling approaches, DreamWeaver will preempt execution to sleep, maximizing time spent at the systems' most efficient operating point. We demonstrate that DreamWeaver can smoothly trade-off bounded, predictable increases in 99th-percentile response time for increasing power savings, and strictly dominates the savings available with voltage and frequency scaling and timeout-based request batching schemes.