Atomic access issues with vars in response_time_distribution.patch

Bug #878022 reported by Laurynas Biveinis
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Percona Server moved to https://jira.percona.com/projects/PS
Fix Released
High
Laurynas Biveinis
5.1
Fix Released
High
Laurynas Biveinis

Bug Description

Even with the bug 803865 fixed, couple of issues with atomic access in the response_time_distribution.patch remain:
1) The i386 CAS inline asm is missing "memory" and "volatile", see comments #10 and #11 at bug 803865. It is very likely that this bug is benign for now, still must be fixed.
2) The time_collector::m_count and m_total variables are declared volatile, which is wrong. Volatility has nothing to do with atomicity, volatile variables are those with unpredictable accesses. Here the accesses are very predictable.

Related branches

Stewart Smith (stewart)
Changed in percona-server:
milestone: none → 5.5.19-25.0
milestone: 5.5.19-24.0 → 5.5.18-23.0
Revision history for this message
Laurynas Biveinis (laurynas-biveinis) wrote :
Revision history for this message
Laurynas Biveinis (laurynas-biveinis) wrote :

Upstream fix in 5.6.16 / 5.7.4.

Revision history for this message
Shahriyar Rzayev (rzayev-sehriyar) wrote :

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-508

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