【正文】 只能發(fā)揮接口卡的１０％性能。然后，多次重復(fù)這樣的測量過程以便得到一個好的平均值。有時候測量結(jié)果初看起來可能不符合直覺，比如在 10， 11， 1 和 2 點鐘網(wǎng)絡(luò)嚴(yán)重?fù)砣?，但是中午時候沒有擁塞（所用的用戶都去吃午飯了）。 （ 3） 改變一個參數(shù)。為了找出真正的問題所在，操作人員必須進(jìn)行測量工作。比如說測量 1 百萬次，然后再取平均。你最好在一個空閑的系統(tǒng)上運行測試過程，并且根據(jù)需要 自己來創(chuàng)建所有的工作負(fù)載。 理解你的測試的指標(biāo) 當(dāng)你要測試讀取一個遠(yuǎn)程文件所需要的時間時，你的測量結(jié)果取決于以下諸多因素；網(wǎng)絡(luò)、客戶和服務(wù)器的操作系統(tǒng)、所使用的硬件接口卡、接口卡的驅(qū)動程序，等等。 通常你只要簡單地溢出緩存的方法就可以避免緩存帶來的問題。（當(dāng)然，有些計算機還有更加精確的時鐘。最基本的一種測量手段是：在開始某一個動作的時候啟動一個定時器，然后確定該需要多長時間。sec, the difference between the two readings will be either 0 or 1, both wrong. However, if the measurement is repeated one million times and the total of all measurements added up and divided by one million, the mean time will be accurate to better than 1 181。以下我們列出其中一部分。s 還要精確得多。 緩沖機制也有類似的影響，一個流行的 TCP/IP 性能測試工具曾經(jīng)報告 UDP可以獲得比物理線路允許的能力還要好得多 的性能。除非你絕對確定自己理解了緩存算法。s,則兩次讀取的時間之差要么是０，要么是１，這兩個結(jié)果都是錯誤的。最后，人們通常對于某些事物的數(shù)量比較感興趣，比如在特定的時間間隔內(nèi)所處理的字節(jié)數(shù)。中文 2100 字 英文翻譯：出自《 Computer Network》第四版 Andrew 著 Network Performance Measurement When a work performs poorly, its users often plain to the folks running it, demanding improvements. To improve the performance, the operators must first determine exactly what is going on. To find out what is really happening, the operators must make measurements. In this section we will look at work performance measurements. The discussion below is based on the work of Mogul (1993). The basic loop used to improve work performance contains the following steps: 1. Measure the relevant work parameters and performance. 2. Try to understand what is going on. 3. Change one parameter. These steps are repeated until the performance is good enough or it is clear that the last drop of improvement has been squeezed out. Measurements can be made in many ways and