文章目录

描述差异的形容词加减乘除倍数表示递进help的用法epoch的用法a prior估计值和真实值的表述比例的表达方式表示哈希表示"被过滤掉"描述计数器/计数值其它

描述差异的形容词

The values in the table show stark differences between applications, both in terms of utilization and of IPG.

加减乘除

Bandwidth is the link utilization multiplied by 10 Gbps.

倍数

Memcached’s replies (server-to-client) have ×2.75 higher 99th percentile utilization than Memcached’s requests(client-to-server).She earns five times as much as I do.She earns five times more than I do.My foot swelled up to three times the normal size when it was stung by a wasp.

表示递进

we only run a small number of applications, which are not representative of today’s heterogeneous data center cloud environment, much less the Internet.

help的用法

Such information can help greatly with traffic engineering and bandwidth provisioning.

epoch的用法

All flow sizes are decoded together at the end of a measurement epoch.

a prior

With the heavy-tailed distribution, the flow sizes are a priori unbounded.

估计值和真实值的表述

$n$ is the total number of flows, ${\hat{f}}_i$ is the estimated size of flow $i$ and $f_i$ the true size.

比例的表达方式

Average error magnitude is defined as the ratio of the sum of absolute errors and the number of errors.Therefore, we know the approximate ratio of the length of the Today and Yesterday against the sliding window.The ratio of men to women at the conference was ten to one/10:1.

表示哈希

Each stage computes an independent hash function on the flow lD of the incoming packets and decides based on it what bucket to add it to.Many flows will typically hash onto a bucket in each stage.A stage is a table of counters which is indexed by a hash function computed on a packet flow ID.When a packet comes in, a hash on its flow ID is computed and the size of the packet is added to the corresponding counter.All packets belonging to the same flow hash to the same counter.When processing a packet with flow ID $e$, we first locate $d_1$ hashed counters at $S_1$ by calculating $d_1$ hashes, and increment the smallest hashed counter(s).We can just use $e$ as the hash key of the $d_2$ hash functions to locate $d_2$ hashed counters at $S_2$.The Usefulness of Multilevel Hash Tables with Multiple Hash Functions in Large Databases

表示"被过滤掉"

This filters out all the small flows that were not lucky enough to hash into a large bucket.

描述计数器/计数值

Onlythe packets that map to counters of $T$ or more at all stages get added to the flow memory.

其它

In a nutshell, Counter Braids “compresses while counting”.since braiding allows more significant bits to be shared among all flows, a reduced number of counters in the higher layers suffice.They’d love to have kids. On the other hand, they don’t want to give up their freedom. (我们可以不用"on the one hand"而直接用"on the other hand", 具体参见此处.)