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https://issues.apache.org/jira/browse/CASSANDRA-14746?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17205922#comment-17205922
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Josh McKenzie commented on CASSANDRA-14746:
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{quote}4.0 should have better latency, more throughput, fewer threads, fewer
context switches, less GC allocation, and faster recovery time.
{quote}
Was this the goal of the MS rewrite? I have no horse in this race - I just
thought the goal of it was to tighten up some of the things that were present /
still troublesome after Jason's rewrite of things rather than specifically
targeting performance improvements.
I'd personally advocate for "no regression on categories a-e" with better
backpressure, tolerance for failure, etc. etc. that I understood to come along
w/the MS rewrite. At least in terms of what we should consider a blocker for
4.0, I think "don't regress" is a stance that makes sense, especially as
incremental performance improvements are reasonable to consider for patch
releases IMO.
And fwiw, the benchmarks I've seen on 4.0 show a pretty significant improvement
in throughput if nothing else, but in terms of bar - no regression for a
rewrite seems like a good low water mark to block on.
> Ensure Netty Internode Messaging Refactor is Solid
> --------------------------------------------------
>
> Key: CASSANDRA-14746
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14746
> Project: Cassandra
> Issue Type: Improvement
> Components: Legacy/Streaming and Messaging
> Reporter: Joey Lynch
> Assignee: Joey Lynch
> Priority: Normal
> Labels: 4.0-QA
> Fix For: 4.0-beta, 4.0-triage
>
>
> Before we release 4.0 let's ensure that the internode messaging refactor is
> 100% solid. As internode messaging is naturally used in many code paths and
> widely configurable we have a large number of cluster configurations and test
> configurations that must be vetted.
> We plan to vary the following:
> * Version of Cassandra 3.0.17 vs 4.0-alpha
> * Cluster sizes with *multi-dc* deployments ranging from 6 - 100 nodes
> * Client request rates varying between 1k QPS and 100k QPS of varying sizes
> and shapes (BATCH, INSERT, SELECT point, SELECT range, etc ...)
> * Internode compression
> * Internode SSL (as well as openssl vs jdk)
> * Internode Coalescing options
> We are looking to measure the following as appropriate:
> * Latency distributions of reads and writes (lower is better)
> * Scaling limit, aka maximum throughput before violating p99 latency
> deadline of 10ms @ LOCAL_QUORUM, on a fixed hardware deployment for 100%
> writes, 100% reads and 50-50 writes+reads (higher is better)
> * Thread counts (lower is better)
> * Context switches (lower is better)
> * On-CPU time of tasks (higher periods without context switch is better)
> * GC allocation rates / throughput for a fixed size heap (lower allocation
> better)
> * Streaming recovery time for a single node failure, i.e. can Cassandra
> saturate the NIC
>
> The goal is that 4.0 should have better latency, more throughput, fewer
> threads, fewer context switches, less GC allocation, and faster recovery
> time. I'm putting Jason Brown as the reviewer since he implemented most of
> the internode refactor.
> Current collaborators driving this QA task: Dinesh Joshi, Jordan West, Joey
> Lynch (Netflix), Vinay Chella (Netflix)
> Owning committer(s): Jason Brown
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