linux绯荤粺IO鎬ц兘娴嬭瘯

Posted 2021-01-26

鏍囩锛?a href='http://www.mamicode.com/so/1/%e7%a8%8b%e5%ba%8f' title='绋嬪簭'>绋嬪簭   澶氭   linu   缂撳瓨   鏃堕棿   code   null   纾佺洏   cache   

dd鍛戒护鑳界矖鐣ユ祴璇曠‖鐩業O鎬ц兘锛屼絾鏄墽琛宒d鍛戒护娴嬭瘯纭洏IO鎬ц兘锛屽纭洏鐨勬崯瀹冲緢澶э紝涓嶅缓璁娆℃垨闀挎椂闂村皾璇?

[[email protected] /]# time dd if=/dev/zero of=/dev/null bs=4k count=256000
256000+0 records in
256000+0 records out
1048576000 bytes (1.0 GB) copied, 0.782804 s, 1.3 GB/s

real    0m0.786s
user    0m0.160s
sys 0m0.626s
[[email protected] /]# time dd if=/dev/zero of=/dev/null bs=4k count=256000 oflag=dsync
256000+0 records in
256000+0 records out
1048576000 bytes (1.0 GB) copied, 0.758887 s, 1.4 GB/s

real    0m0.762s
user    0m0.120s
sys 0m0.642s
[[email protected] /]# time dd if=/dev/zero of=/dev/null bs=4k count=256000 conv=fdatasync
dd: fsync failed for 鈥?dev/null鈥? Invalid argument
256000+0 records in
256000+0 records out
1048576000 bytes (1.0 GB) copied, 0.514259 s, 2.0 GB/s

real    0m0.518s
user    0m0.128s
sys 0m0.390s
[[email protected] /]# 

oflag=dsync锛歞d浼氫粠/dev/zero涓紝姣忔璇诲彇4Kbytes鏁版嵁锛岀劧鍚庣洿鎺ュ啓鍏ュ埌纭洏褰撲腑锛岄噸澶嶆姝ラ锛岀洿鍒板叡璇诲彇骞朵笖鍐欏叆浜? Gbytes鐨勬暟鎹€傝繖涓繃绋嬪彲鑳戒細寰堟參锛屽洜涓烘病鏈夌敤鍒板啓缂撳瓨锛坵rite cache锛夛紝鍔犳鍙傛暟锛屽彲浠ユā鎷熸暟鎹簱鐨勬彃鍏ユ搷浣滐紝鍙兘璺熸帴杩戠湡瀹炪€?/p>

conv=fdatasync锛歞d浼氫粠/dev/zero涓竴娆℃€ц鍙? Gbytes鐨勬暟鎹紝鍐欏叆鍒扮鐩樼殑缂撳瓨涓紝鐒跺悗鍐嶄粠纾佺洏缂撳瓨涓鍙栵紝涓€娆℃€у啓鍏ュ埌纭洏褰撲腑銆?/p>

time鍛戒护鐢ㄦ潵璁＄畻dd绋嬪簭鐨勮繍琛岃€楁椂(real)锛?鐢ㄦ埛鎬乧pu鑰楁椂(user)锛?绯荤粺鎬乧pu鑰楁椂(sys)銆?br/>real : 琛ㄧずfoo绋嬪簭鏁翠釜鐨勮繍琛岃€楁椂銆傚彲浠ョ悊瑙ｄ负foo杩愯寮€濮嬫椂鍒讳綘鐪嬩簡涓€涓嬫墜琛紝foo杩愯缁撴潫鏃讹紝浣犲張鐪嬩簡涓€涓嬫墜琛紝涓ゆ鏃堕棿鐨勫樊鍊煎氨鏄湰娆eal 浠ｈ〃鐨勫€?br/>user锛氳繖涓椂闂翠唬琛ㄧ殑鏄痜oo杩愯鍦ㄧ敤鎴锋€佺殑cpu鏃堕棿锛?br/>sys: 杩欎釜鏃堕棿浠ｈ〃鐨勬槸foo杩愯鍦ㄦ牳蹇冩€佺殑cpu鏃堕棿銆?/p>