Chrome Timeline指標說明：Blocked、Connect、Send、Waiting、Receiving

muyable 2015-09-30

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Blocked time includes any pre-processing time (such as cache lookup) and the time spent waiting for a network connection to become available. Internet Explorer will only create a maximum of two concurrent network connections per host name (i.e. www.microsoft.com) and will queue up requests until a network connection is available. Often the Blocked time is the most significant factor in the download time of images embedded in a web page.
閉塞時間，包括所有的過程之前的時間（像，cache對比）和等待網(wǎng)絡鏈接的時間，IE在每個主機名（像 http://www.microsoft.com/）下最多只創(chuàng)建兩個當前的網(wǎng)絡連接，而且要排隊等待直到這個網(wǎng)絡鏈接可用，通常，閉塞時間影響網(wǎng)頁中圖片加載時間的重要因素。
Connect is the time required to create a TCP connection to the web server (or proxy). If a secure HTTPS connection is being used this time includes the SSL handshake process. Keep-Alive connections are often used to avoid the overhead of repeatedly connecting to the web server.
連接時間，是創(chuàng)建TCP連接到服務器或者代理服務器所花費的時間，如果一個包含SSL的安全的HTTPS連接存在，Keep-Alive鏈接經(jīng)常被用到，以避免多次重復的連接WEB服務器。
Send is the time required to send the HTTP request message to the server and will depend on the amount of data that is sent to the server. For example, long Send times will result from uploading files using an HTTP POST
發(fā)送，是發(fā)送HTTP請求到服務器的時間，而且這個時間取決與發(fā)送請求的數(shù)據(jù)量的大小，例如，長的發(fā)送時間是由于用 PSOT方式上傳文件造成的。
Wait is the idle time spent waiting for a response message from the server. This value includes delays introduced due to network latency and the time required to process the request on the web server.
等待，是花費在等待服務器響應消息的空閑時間，這個值包括網(wǎng)絡延遲和服務器處理請求的時間。
Receive is the time taken to read the response message from the server. This value will be depend on the size of the content returned, network bandwidth and whether HTTP compression was used.
接收，是花費在從服務器讀取響應消息的時間。這個值可以受到請求消息內(nèi)容的大小，網(wǎng)絡帶寬和是否使用了HTTP壓縮。
Cache Read is the time taken to read the content from the browser cache during (Cache) or 304 responses.
緩存讀取，是花費在從瀏覽器緩存中讀取內(nèi)容或者304響應的時間。
TTFB (or Time To First Byte) is the duration from the initial network request being initiated by the browser to the first byte being received from the server. It includes TCP connection time, the time to send the request and the time taken to get the first byte of the response message.
TTFB，是最初的網(wǎng)絡請求被發(fā)起到從服務器接收到第一個字節(jié)這段時間，它包含了TCP連接時間，發(fā)送HTTP請求時間和獲得響應消息第一個字節(jié)的時間。