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Description of problem:
When running UnixBench5.1.3 tests on a RHEL6.4 system with the latest glibc version there is a noticeable performance loss in the double-whetstone test (around 50% difference).  When using the patched glibc from BZ964044, http://people.redhat.com/yoguma/.bz892635 there is still about a 20% loss in performance.

Version-Release number of selected component (if applicable):
glibc-2.12-1.107.el6.x86_64
glibc-2.12-1.107.el6.1.bz892635.x86_64

How reproducible:
always.

Steps to Reproduce:
- Build a RHEL6.3 x86_64 system, mine is built with 4 CPU, 4GB memory.
- Download, compile UnixBench5.1.3.tgz from http://code.google.com/p/byte-unixbench/downloads/list
- The one benchmark number they are checking on is the double-whetstone run, the others are within a <10% gap which they seem to be satisfied with.
# ./Run -c 1 -i 20 whets
- gather the Results
- Build a RHEL6.4.z system with latest packages and run UnixBench, gather results
- Install the patch glibc packages from here: http://people.redhat.com/yoguma/.bz892635/ and rebuild, re-run UnixBench. gather results.

Actual results: RHEL6.4.z glibc run is 40% slower than 6.3, and 6.4 + patch glibc is still 20% slower than 6.3.


Expected results: 
Same or better performance.


Additional info:

I'll take this.

Created attachment 758173 [details]
Candidate fix

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2013-1605.html