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List:       activemq-dev
Subject:    [jira] [Updated] (AMQCPP-498) Client doesn't work on Linux Red Hat 6.4 systems, fails when setting t
From:       "John Rocha (JIRA)" <jira () apache ! org>
Date:       2013-06-28 23:28:20
Message-ID: JIRA.12655441.1372461985453.186791.1372462100638 () arcas
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     [ https://issues.apache.org/jira/browse/AMQCPP-498?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel \
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John Rocha updated AMQCPP-498:
------------------------------

    Attachment: patch.TBD

proposed patch which:
# validates the return values of all pthread calls and
# only sets the priority iff the policy is set to SCHED_FIFO or SCHED_RR

                
> Client doesn't work on Linux Red Hat 6.4 systems, fails when setting thread \
>                 priority
> ------------------------------------------------------------------------------------
>  
> Key: AMQCPP-498
> URL: https://issues.apache.org/jira/browse/AMQCPP-498
> Project: ActiveMQ C++ Client
> Issue Type: Bug
> Components: Decaf
> Affects Versions: 3.5.0
> Environment: Linux Red Hat 6.4
> Reporter: John Rocha
> Assignee: Timothy Bish
> Priority: Critical
> Labels: decaf, priority, pthreads, scheduling, thread
> Attachments: patch.TBD
> 
> 
> Client doesn't work on Linux Red Hat 6.4 systems. It fails throwing the exception \
> {panel}Failed to set new Therad priority to value: 18{panel} This is coming from \
> the file {{{color:brown}src/main/decaf/internal/util/concurrent/unix/PlatformThread.cpp{color}}}
>  when it's creating a new thread.
> We encountered this problem when we started running our code on a new operating \
> system. It worked fine on Redhat 5.8 and SuSE SLES10, but then it started failing \
> on Redhat 6.4. I did some digging and found a defect logged against the _+pthread+_ \
> library at: http://sourceware.org/bugzilla/show_bug.cgi?id=10828. {panel}(This \
> problem was found by analyzing a failure of LSB distribution compliance test, \
> lsb-runtime, v. 4.0.2.) A relatively new change in \
> $GITROOT/glibc/nptl/pthread_attr_setschedparam.c (2009-04-23 according to git) adds \
> a check to pthread_attr_setschedparam() call whether the priority being set is \
> compatible with the scheduling policy already set in the structure; if the priority \
> is not in the prescribed range, it fails, generating the EINVAL error. This check, \
> although well intended, has a side effect that can break existing code (at least \
> the LSB tests): it makes the process of initializing a pthread_attr structure \
> order-dependent on Linux. As Linux does not use the numeric priority for \
> SCHED_OTHER, which is the default, and sched_get_priority_min() and \
> sched_priority_max() return 0. Therefore: If a programmer calls \
> pthread_attr_init(), then pthread_attr_setschedpolicy() to set SCHED_RR or \
> SCHED_FIFO, and then pthread_attr_setschedparam(), it works. But if the other way \
> around (priority first, then scheduling policy), it fails for "no apparent \
> reason".{panel} I did some debugging in the code and found that \
> {{unix/PlatformThread.cpp}}'s method {{createNewThread()}} sets the scheduling \
> priority but doesn't set the scheduling policy. And the default value for the \
> scheduling policy is SCHED_OTHER(0) which only supports a priority value of 0. I \
> have a proposed patch which: # validates the return values of all pthread calls and
> # only sets the priority iff the policy is sset to SCHED_FIFO or SCHED_RR
> Granted, we never set the policy so one could argue that we should just remove \
> setting of the priority. However, I suspect that the true desire is to inherit the \
> current threads scheduling value and set the priority based on that. So I \
> anticipate tha future changes may actually set the policy. I didn't do this though.

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