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https://issues.apache.org/jira/browse/MAPREDUCE-6391?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14977780#comment-14977780
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Hudson commented on MAPREDUCE-6391:
-----------------------------------
FAILURE: Integrated in Hadoop-Hdfs-trunk #2482 (See
[https://builds.apache.org/job/Hadoop-Hdfs-trunk/2482/])
MAPREDUCE-6391. util/Timer.cc completely misunderstands _POSIX_CPUTIME (aw: rev
bcc4c746a88cc698b2937b85ec845b9d8cc736d2)
* hadoop-mapreduce-project/CHANGES.txt
*
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-nativetask/src/main/native/src/util/Timer.cc
fix changes.txt for MAPREDUCE-6391. (aw: rev
0e344902aaca417813c7191395cd5c73dfcd4220)
* hadoop-mapreduce-project/CHANGES.txt
> util/Timer.cc completely misunderstands _POSIX_CPUTIME
> ------------------------------------------------------
>
> Key: MAPREDUCE-6391
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6391
> Project: Hadoop Map/Reduce
> Issue Type: Sub-task
> Components: build
> Affects Versions: 3.0.0
> Reporter: Alan Burlison
> Assignee: Alan Burlison
> Fix For: 3.0.0
>
> Attachments: MAPREDUCE-6391.001.patch
>
>
> util/Timer.cc contains the following code:
> clock_gettime(_POSIX_CPUTIME, &ts);
> I'm not exactly sure what sort of time value this code is attempting to
> obtain (the process's on-CPU time perhaps?) but it is completely wrong, even
> on Linux. _POSIX_CPUTIME is a feature test macro and is *not* a valid
> parameter to clock_gettime. From the clock_gettime manpage:
> bq. The symbols _POSIX_MONOTONIC_CLOCK, _POSIX_CPUTIME, _POSIX_THREAD_CPUTIME
> indicate that CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID,
> CLOCK_THREAD_CPUTIME_ID are available
> On my Linux distro the value of _POSIX_CPUTIME is defined as 0. That
> corresponds to
> bq. #define __CLOCK_REALTIME0 0 /* obsolete; same as
> CLOCK_REALTIME */
> And CLOCK_REALTIME is
> bq. #define CLOCK_REALTIME 3 /* wall clock */
> Which I suspect is not what is required here.
> Getting cross-platform CPU time is fiddly, the following blog post has a good
> summary:
> http://nadeausoftware.com/articles/2012/03/c_c_tip_how_measure_cpu_time_benchmarking
> (code examples are CC licensed so should be no taint issues)
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