全部博文（436）
分类： LINUX
2012-12-24 20:01:49
1、引言
Our key idea is thus simple: measure the number of cycles spent by threads waiting for each bottleneck and accelerate the bottlenecks responsible for the highest thread waiting cycles.
我们主要的想法就是：测量线程等待每一个瓶颈的周期数，并加速负责最高线程等待周期的瓶颈。
This solution is too costly because (a) writing correct parallel programs is already a daunting task, and (b) serializing bottlenecks change with machine configu- ration, program input set, and program phase (as we show in Sec- tion 2.2), thus, what may seem like a bottleneck to the programmer may not be a bottleneck in the field and vice versa.
这个解决方法代价很高因为（a）程序员写并行程序是一个艰巨的任务（b）一系列的瓶颈会随着机器配置、程序输入集、程序计划阶段改变而改变，所以是不是一个瓶颈不一定
The programmer, compiler or library delimits potential bot- tlenecks using BottleneckCall and BottleneckReturn instructions, and replaces the code that waits for bottlenecks with a Bottleneck- Wait instruction.
程序员利用BottleneckCall和BottleneckReturn指令分割潜在的瓶颈，用Bottleneck-Wait指令代替等待瓶颈的代码
The bottlenecks with the highest number of thread waiting cycles are selected for acceleration on one or more large cores. On executing a BottleneckCall instruction, the small core checks if the bottleneck has been selected for acceleration.
最高线程等待的周期的瓶颈被选择为加速在一个或多个大核上。在执行BC指令时小核检查瓶颈是否被选择为加速
How- ever, it only applies to barriers in statically scheduled workloads, where the work to be performed by each thread is known before runtime.
只适用于静态调度的障碍
3.3 加速瓶颈
BIS, consists of two parts: identification of critical bottlenecks and acceleration of those bottlenecks.
BIS，包括两部分：识别临界瓶颈并且加速这些瓶颈。
Identification of critical bottlenecks is done in hardware based on information provided by the software.
识别临界瓶颈是在软件提供的信息基础上在硬件上实现的。
There are multiple ways to accelerate a bottleneck, e.g. increasing core frequency, giving a thread higher priority in shared hard- ware resources, or migrating the bottleneck to a faster core with a more aggressive microarchitecture or higher frequency.
有许多方法加速瓶颈，例如提高核的频率，共享硬件资源给一个线程更高的优先权，或者把瓶颈移到有更积极的微体系结构建模或更高频率的核中。
问题：
1. However, these proposals lack generality and finegrained adaptivity.中的finegrained 怎么理解（细粒）
