How dose pipe work in aufs ?

Dear friends

        I had take a experiment today, and fund that the pipe mechanism is not necessary for aufs.
It can not improve the performance,but a little depress
        I use squid2.5-STABLE4 in a vmware linux OS, 64M mem. aufs 100 16 254.
        Polygraph 2.6.7, use 1000robots*0.2req/sec*13kB, cacheable=100% recurrence=100%
When use squid2.5-STABLE4 without anything changed, the average response time was about 24ms.
Then I changed the code, comment the operation of read from and write to pipe, then I see the
average response time turned to 20ms.
        I know that the pipe is the mechanism to force the main process to resume when an disk
I/O operation have completed. but I had inspect the source code, found the pipe was set non-
blocked. and the callback function of the pipe just read characters from the pipe. Then how
dose a non-blocked pipe force the main process to resume?

　　　　　　　　htxia@wtwh.com.cn
　　　　　　　　　　2004-02-16
Received on Mon Feb 16 2004 - 02:26:38 MST