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Description of problem:

Customer has found a possible lock contention on glibc's localtime_r() and asked to backport it. All RHEL variables from 4 to 7 don't have this fix.

"This patch is an "easy win" partial fix for BZ #16145, which notes
the heavy contention on tzset_lock when multiple threads are converting
times with localtime_r().

In __tz_convert(), the lock does not need to be held after
__tzfile_compute() / __tz_compute() have been called, so we can move the
unlock up.  At this point there is still significant work to be done in
__offtime(), so we see some improvement (in my testing with 8 cores
banging on localtime_r(), ~20% improvement in throughput)."
-- https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=6807b1db8233ed84671f061b5d825622233df303


Version-Release number of selected component (if applicable):
- glibc-2.12-1.149.el6


How reproducible:
- 100% 


Steps to Reproduce:
1. No sure at this moment 
2.
3.


Actual results:
- No fix 

Expected results:
- Apply the upstream fix 


Additional info:

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.

https://rhn.redhat.com/errata/RHBA-2016-0834.html