[SERVER-16572] Add counter for calls to sched_yield in WiredTiger Created: 17/Dec/14 Updated: 15/Jan/15 Resolved: 02/Jan/15 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Diagnostics, Performance, Storage |
| Affects Version/s: | None |
| Fix Version/s: | 2.8.0-rc5 |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Bruce Lucas (Inactive) | Assignee: | Susan LoVerso |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Backwards Compatibility: | Fully Compatible | ||||||||
| Participants: | |||||||||
| Description |
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It appears that calls to sched_yield can be associated with performance issues; see for example this ticket. So it could be useful if the performance metrics included a counter for calls to sched_yield. |
| Comments |
| Comment by Eliot Horowitz (Inactive) [ 21/Dec/14 ] |
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I don't think is going to add anything. The variably in cpu spin times and scheduling is going to market this incredibly erratic and noisy. And it could easily be a perf hit. Time would be useful but even more expensive. |
| Comment by Charlie Page [ 18/Dec/14 ] |
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If these stats are tied into mongtop, etc this strategy needs to consider how the stats are reported on long waits (i.e. would this cause a wait not to even be seen until it's completed?) |