Bad file access on the rise

[Steve Grubb]

On Saturday, June 08, 2013 09:57:03 AM Doug Ledford wrote:
> Bad test.  The first run took the hit for getting the file info into
> page cache, after that, everything was run from cache and you got the
> second result above and the results below.  You have to make sure that
> from run to run the cache state of the file in question is identical.

Try it yourself.  :-)  I know what you are saying and run the test probably 8 
times before posting results. I also have the audit rule loaded...so removing 
it:

[sgrubb at x2 noatime]$ time ./test noatime

real	0m0.031s
user	0m0.006s
sys	0m0.024s
[sgrubb at x2 noatime]$ time ./test noatime

real	0m0.033s
user	0m0.002s
sys	0m0.032s
[sgrubb at x2 noatime]$ time ./test noatime

real	0m0.036s
user	0m0.002s
sys	0m0.031s
[sgrubb at x2 noatime]$ time ./test atime

real	0m0.023s
user	0m0.001s
sys	0m0.021s
[sgrubb at x2 noatime]$ time ./test atime

real	0m0.022s
user	0m0.003s
sys	0m0.019s
[sgrubb at x2 noatime]$ time ./test atime

real	0m0.023s
user	0m0.002s
sys	0m0.019s

Without the audit rules, it is faster. But again opening with noatime 
attempted is measurably slower.

-Steve