查詢各個連接階段所花費的時間，例如 DNS查詢時間、下載時間、SSL連接花費的時間...
把這段存為 curltime.sh
curl -w @- -o /dev/null -s "$@" <<'EOF'
time_namelookup: %{time_namelookup}\n
time_connect: %{time_connect}\n
time_appconnect: %{time_appconnect}\n
time_pretransfer: %{time_pretransfer}\n
time_starttransfer: %{time_starttransfer}\n
----------\n
time_total: %{time_total}\n
speed_download: %{speed_download} bytes/s\n
EOF
用法：
$ ./curltime.sh https://www.pchome.com.tw/ time_namelookup: 0.001854 DNS 查詢花費的時間 time_connect: 0.013127 TCP Connection，也就是 TCP 三向交握的时间(Three Way Handshake） time_appconnect: 0.067827 SSL/TSL handshake 的時間 (若是 http 這兒就是 0) time_pretransfer: 0.068630 time_starttransfer: 0.086331 發出 request 後直到收到網頁的第一字元花費的時間(FTTB) ---------- time_total: 0.188357 speed_download: 1042845.000 bytes/s參考：
Timing Details With cURL
time_pretransfer：
The time, in seconds, it took from the start until the file transfer was just about to begin. This includes all pre-transfer commands and negotiations that are specific to the particular protocol(s) involved.
其它 curl 變數：
http_code The numerical response code that was found in the last retrieved HTTP(S) or FTP(s) transfer. In 7.18.2 the alias response_code was added to show the same info.
http_connect The numerical code that was found in the last response (from a proxy) to a curl CONNECT request. (Added in 7.12.4)
http_version The http version that was effectively used. (Added in 7.50.0)
local_ip The IP address of the local end of the most recently done connection - can be either IPv4 or IPv6 (Added in 7.29.0)
local_port The local port number of the most recently done connection (Added in 7.29.0)
num_connects Number of new connects made in the recent transfer. (Added in 7.12.3)
num_redirects Number of redirects that were followed in the request. (Added in 7.12.3)
response_code The numerical response code that was found in the last transfer (formerly known as "http_code"). (Added in 7.18.2)
scheme The URL scheme (sometimes called protocol) that was effectively used (Added in 7.52.0)
size_download The total amount of bytes that were downloaded.
size_header The total amount of bytes of the downloaded headers.
size_request The total amount of bytes that were sent in the HTTP request.
size_upload The total amount of bytes that were uploaded.
speed_download The average download speed that curl measured for the complete download. Bytes per second.
speed_upload The average upload speed that curl measured for the complete upload. Bytes per second.
ssl_verify_result The result of the SSL peer certificate verification that was requested. 0 means the verification was successful. (Added in 7.19.0)
time_appconnect The time, in seconds, it took from the start until the SSL/SSH/etc connect/handshake to the remote host was completed. (Added in 7.19.0)
time_connect The time, in seconds, it took from the start until the TCP connect to the remote host (or proxy) was completed.
time_namelookup The time, in seconds, it took from the start until the name resolving was completed.
time_pretransfer The time, in seconds, it took from the start until the file transfer was just about to begin. This includes all pre-transfer commands and negotiations that are specific to the particular protocol(s) involved.
time_redirect The time, in seconds, it took for all redirection steps including name lookup, connect, pretransfer and transfer before the final transaction was started. time_redirect shows the complete execution time for multiple redirections. (Added in 7.12.3)
time_starttransfer The time, in seconds, it took from the start until the first byte was just about to be transferred. This includes time_pretransfer and also the time the server needed to calculate the result.
time_total The total time, in seconds, that the full operation lasted.
url_effective The URL that was fetched last. This is most meaningful if you've told curl to follow location: headers.
完整資料： https://curl.haxx.se/docs/manpage.html
httpstat
另外有個 httpstat 工具把上面 curl 的結果畫成更易理解的圖表
https://github.com/davecheney/httpstat
It's like curl -v, with colours.
$ ./httpstat.py https://www.yahoo.com.tw/ Connected to 124.108.115.101:443 from 192.168.0.4:55853 HTTP/2 301 date: Sun, 14 Jun 2020 03:14:51 GMT p3p: policyref="https://policies.yahoo.com/w3c/p3p.xml" cache-control: max-age=3600, public location: https://tw.yahoo.com/ content-length: 0 content-type: text/html; charset=UTF-8 :::略過header::: DNS Lookup TCP Connection TLS Handshake Server Processing Content Transfer [ 5ms | 15ms | 45ms | 16ms | 0ms ] | | | | | namelookup:5ms | | | | connect:20ms | | | pretransfer:65ms | | starttransfer:81ms | total:81ms
備註
Server Processing = time_starttransfer - time_pretransfer
TLS Handshake = time_pretransfer - time_connect
