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https://issues.apache.org/jira/browse/TS-162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12848840#action_12848840
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John Plevyak commented on TS-162:
---------------------------------
The uses of RecGetGLobalRawStatSum in Cache.cc
AIO_Callback_handler::handle_disk_failure
should be incr.
iocore/aio/AIO.cc has thread-unsafe statistics: global non-volatile variables
updated
with normal increment then copied into the global stats.
> inconsistencies in the stats system - there are incorrect assumtions on
> sychronization between threads
> ------------------------------------------------------------------------------------------------------
>
> Key: TS-162
> URL: https://issues.apache.org/jira/browse/TS-162
> Project: Traffic Server
> Issue Type: Bug
> Components: Stats
> Reporter: Bryan Call
> Assignee: Bryan Call
> Fix For: 2.0.0
>
> Attachments: stats_bcall_001.diff
>
>
> There is a problem with the current stats being inconsistent. The problem is
> that the net threads each have their own stats which they modify and the
> aggregation thread also modifies the same stat value. There is no proper
> synchronization for this to work correctly. The aggregation thread does an
> atomic swap to zero the net threads stat value, but the local thread doesn't
> use atomics and only increments the value. This will lead to
> inconsistencies...
> A better design is to *only* have the net threads modify their local stats
> and have the aggregation thread handle totalling the values in a separate
> stat structure.
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