Details
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Bug
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Resolution: Fixed
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Critical
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5.5.0
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Untriaged
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Yes
Description
Broken out from MB-28409 - investigation shows a ~3% drop in pillowfight throughput between 1701 and 1714:
Changes in this range in KV-Engine (http://172.23.123.43:8000/getchangelog?product=couchbase-server&fromb=5.5.0-1701&tob=5.5.0-1714) are mostly test changes - the only patch which could plausibly trigger the slowdown is:
* Commit: 597c51f86fd8921fdc45b9a4bd39a4dd3c2ce86b
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MB-22010: Introduce Frequency Counter to StoredValue
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Adds a frequency counter to StoredValue, which is held in the "value"
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SingleThreadedRCTaggedPtr. Therefore it does not use any extra memory.
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The counter is a uint16_t.
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An associated get and set method are provided together with a regression
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test.
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The patch increments the frequency counter when the StoredValue is
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referenced from the the hashtable, (this is at the same point as
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where the existing NRU counter is updated). This completes the basic
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framework needed to experiment with different hash table eviction
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policies.
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Change-Id: I939eb9ebd7bf99da6bc0eb4b5fd659a97b80d662
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Reviewed-on: http://review.couchbase.org/87524
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Reviewed-by: Dave Rigby <daver@couchbase.com>
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Tested-by: Build Bot <build@couchbase.com>
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Attachments
Issue Links
- causes
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- Closed
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| For Gerrit Dashboard: MB-28940 | ||||||
|---|---|---|---|---|---|---|
| # | Subject | Branch | Project | Status | CR | V |
| 91749,10 | MB-28940: Add benchmark for StatisticalCounter::generateValue | master | kv_engine | Status: MERGED | +2 | +1 |
| 91756,5 | MB-28940: Remove lock usage from StatisticalCounter | master | kv_engine | Status: MERGED | +2 | +1 |
| 91810,2 | Revert "MB-28940: Remove lock usage from StatisticalCounter" | master | kv_engine | Status: MERGED | +2 | +1 |
| 91832,7 | MB-28940: Remove lock usage from StatisticalCounter | master | kv_engine | Status: MERGED | +2 | +1 |