RFR: 8185525: [Event Request] Add Tracing event for DictionarySizes

gerard ziemski gerard.ziemski at oracle.com
Wed Apr 3 15:24:49 UTC 2019

Hi all,

Please review this feature, which adds tracing events for the internal 
hash tables.

The following attributes are implemented:

<Field type="ulong" name="numberOfBuckets" label="Number of buckets" 
description="Number of buckets" />
<Field type="ulong" name="numberOfEntries" label="Number of entries" 
description="Number of all entries" />
<Field type="ulong" contentType="bytes" name="totalFootprint" 
label="Total footprint" description="Total memory footprint (the table 
itself plus all of the entries)" />
<Field type="ulong" name="maximumBucketSize" label="Maximum bucket size" 
description="The maximum bucket length (entries in a single bucket)" />
<Field type="double" name="averageBucketSize" label="Average bucket 
size" description="The average bucket length (entries in a bucket)" /> 
<Field type="double" name="varianceOfBucketSize" label="Variance of 
bucket sizes" description="How far bucket lengths are spread out from 
their average value" />
<Field type="double" name="stdDevOfBucketSize" label="Standard deviation 
of bucket sizes" description="How far bucket lengths are spread out from 
their mean (expected) value" />
<Field type="double" name="addRate" label="Rate of addition" 
description="How many items were added since last event (per second)" />
<Field type="double" name="removeRate" label="Rate of removal" 
description="How many items were removed since last event (per second)" />

This event was implemented for the following system tables:

Placeholder Table
LoaderConstraints Table
ProtectionDomainCache Table

Webrev:  http://cr.openjdk.java.net/~gziemski/8185525_rev1/
Bug:     https://bugs.openjdk.java.net/browse/JDK-8185525
Testing: Mach5 tier1,2,3 (another Mach5 tier1,2,3,4,5,6,7 in progress…)


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