APAR status
Closed as program error.
Error description
A significant performance degradation has been noticed in the std::sort routine on AIX when compared to other platforms.
Local fix
N/A
Problem summary
USERS AFFECTED: Users who use the sort in STL are potentially affected by this issue. PROBLEM DESCRIPTION: Sorting takes twice as much time than using other compilers when repeating every 100 values many times. The current sorting algorithm used in the XLC++ STL does not perform well with certain patterns, especially when there are a lot of repeated values. Changed the alogorithm to use a fat pivot rather than a single element as a pivot. This gives much better performance.
Problem conclusion
The current implementation of sorting is too simplistic and does not perform well. It should be re-implemented with a more sophisticated algorithm.
Temporary fix
Comments
APAR Information
APAR number
IV31591
Reported component name
XL C/C++ RUNTIM
Reported component ID
5725C7201
Reported release
C10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-11-07
Closed date
2012-11-07
Last modified date
2012-11-07
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
XL C/C++ RUNTIM
Fixed component ID
5725C7201
Applicable component levels
RC10 PSY U856069
UP C
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