[SERVER-15950] Reduce contention on groupCommitMutex in MMAP V1 Created: 04/Nov/14 Updated: 19/Nov/14 Resolved: 06/Nov/14 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Concurrency |
| Affects Version/s: | 2.7.8 |
| Fix Version/s: | 2.8.0-rc0 |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Davide Italiano | Assignee: | Mathias Stearn |
| Resolution: | Done | Votes: | 0 |
| Labels: | 28qa | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
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| Backwards Compatibility: | Fully Compatible | ||||
| Operating System: | ALL | ||||
| Steps To Reproduce: | Run sysbench (https://github.com/tmcallaghan/sysbench-mongodb) |
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| Description |
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On insert-only workload (e.g. sysbench first phase), groupCommitMutex shows up as the most congested lock. Attached the Vtune lock profiler output as an evidence |
| Comments |
| Comment by Githook User [ 06/Nov/14 ] |
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Author: {u'username': u'RedBeard0531', u'name': u'Mathias Stearn', u'email': u'mathias@10gen.com'}Message:
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| Comment by Kaloian Manassiev [ 05/Nov/14 ] |
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Note that this is specific to MMAP V1, in case you were trying with other storage engines. Disabling journaling should help. |
| Comment by Tim Callaghan [ 05/Nov/14 ] |
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Is this gating the performance improvement I'd expect to see with collection level locking? Is disabling journaling a work-around for now? |