????sudo apachectl restart
????2.????????????????
??ab -n 4 -c 2 https://www.baidu.com/
????-n?????????????
????-c????????????

??????Requests per second ??????
???????????????????/?????????Щ??????????????????
????Request per second=Complete requests/Time taken for tests
??????Concurrency Level ?????????
??????????????????????????????????????????????????????????????????????????HTTP/1.1?￡?IE7????????????????IE8???6???????????FireFox3???4???????????????????????????????????ó????????????
??????Time per request ???????????????
??????????????????????????????????????/??????????/?????????????????
????Time per request=Time taken for tests/??Complete requests/Concurrency Level??
??????Time per request:across all concurrent requests ??????????????????
??????????????????????????????????????/??????????????
????Time taken for/testsComplete requests