On 01/27/2012 05:57 PM, John Ellson wrote:
On 01/27/2012 08:10 AM, Harald Hoyer wrote:
Hello Testers and rawhide Users,
Fedora 17 will locate the entire base operating system in /usr. The
directories
/bin, /sbin, /lib, /lib64 will only be symlinks:
/bin → /usr/bin
/sbin → /usr/sbin
/lib → /usr/lib
/lib64 → /usr/lib64
Mostly worked as described.
One issue is that the default user's PATH needs to be cleaned up:
/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/guest/.local/bin:/home/guest/bin
...
There may be a similar problem with ldconfig. At the moment
"ldconfig -p" show most libs being resolved from /lib instead of from
/usr/lib.
I'm not against this change, but it would be better if it resulted in a
performance gain rather than a performance loss.
I wrote a test to stat() the 2000+ files in /usr/bin/*, or /bin/*, 100
times.
The time cost of a stat() of /usr/bin/foo was ~ 12.4 microseconds; the
time cost of a stat() of /bin/foo was ~17.8 microseconds.
So to me, it is important that the default PATHs are changed to minimize
the traversal of softlinks.
At the moment, having /bin early in the PATH means that a softlink has
been *introduced* into most lookups, thus degrading performance.
The same issue exists for libs.
John
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