[
https://issues.apache.org/jira/browse/CASSANDRA-7061?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14715420#comment-14715420
]
Richard Lewis commented on CASSANDRA-7061:
------------------------------------------
Customers consistently question the value of metrics provided through tracing
in comparison to what Opscenter reports. It compromises their confidence in C*
when our measurements are so far off. Explaining the differences away by
telling them it's the overhead of client communications and tracing overhead is
hard for them to digest. We need something that is reporting more realistic
metrics for tracing.
> High accuracy, low overhead local read/write tracing
> ----------------------------------------------------
>
> Key: CASSANDRA-7061
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7061
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Benedict
>
> External profilers are pretty inadequate for getting accurate information at
> the granularity we're working at: tracing is too high overhead, so measures
> something completely different, and sampling suffers from bias of attribution
> due to the way the stack traces are retrieved. Hyperthreading can make this
> even worse.
> I propose to introduce an extremely low overhead tracing feature that must be
> enabled with a system property that will trace operations within the node
> only, so that we can perform various accurate low level analyses of
> performance. This information will include threading info, so that we can
> trace hand off delays and actual active time spent processing an operation.
> With the property disabled there will be no increased burden of tracing,
> however I hope to keep the total trace burden to less than one microsecond,
> and any single trace command to a few tens of nanos.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
