[
https://issues.apache.org/jira/browse/CASSANDRA-19429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17900137#comment-17900137
]
Dipietro Salvatore commented on CASSANDRA-19429:
------------------------------------------------
When I was testing it Cassandra 5 few months back, it was fine and inline with
the patch performance. Of course, increasing the number of cores, the
contention become more evident and there is more performance gain as well but I
have recorded significant improvement on smaller instances as well. For example
on 4xl instance (16 cores) I have recorded up to 43% gain on different
architectures (x86, aarch64) which, in my opinion, is a good gain considering
also the size of the change and how many users are not migrated yet to
Cassandra 5 and still using Cassandra 4.x.
Here are the data that I have collected few months back:
|Instance type|threads|Cass 4.1.3|Cass 4.1.3 patched|
|r8g.4xlarge|400|120k|167k (1.39x)|
|r8g.24xlarge|400|168k|496k (2.95x)|
|r7g.4xlarge|400|81k|118.7k (1.42x)|
|r7g.16xlarge|400|146k|317k (2.5x)|
|r7i.4xlarge|400|87k|125k (1.43x)|
|r7i.24xlarge|400|153k|304k (1.98x)|
> Remove lock contention generated by getCapacity function in SSTableReader
> -------------------------------------------------------------------------
>
> Key: CASSANDRA-19429
> URL: https://issues.apache.org/jira/browse/CASSANDRA-19429
> Project: Cassandra
> Issue Type: Bug
> Components: Local/SSTable
> Reporter: Dipietro Salvatore
> Assignee: Dipietro Salvatore
> Priority: Normal
> Fix For: 4.0.x, 4.1.x
>
> Attachments: Screenshot 2024-02-26 at 10.27.10.png, Screenshot
> 2024-02-27 at 11.29.41.png, Screenshot 2024-03-19 at 15.22.50.png,
> asprof_cass4.1.3__lock_20240216052912lock.html,
> image-2024-03-08-15-51-30-439.png, image-2024-03-08-15-52-07-902.png
>
> Time Spent: 3h 50m
> Remaining Estimate: 0h
>
> Profiling Cassandra 4.1.3 on large AWS instances, a high number of lock
> acquires is measured in the `getCapacity` function from
> `org/apache/cassandra/cache/InstrumentingCache` (1.9M lock acquires per 60
> seconds). Based on our tests on r8g.24xlarge instances (using Ubuntu 22.04),
> this limits the CPU utilization of the system to under 50% when testing at
> full load and therefore limits the achieved throughput.
> Removing the lock contention from the SSTableReader.java file by replacing
> the call to `getCapacity` with `size` achieves up to 2.95x increase in
> throughput on r8g.24xlarge and 2x on r7i.24xlarge:
> |Instance type|Cass 4.1.3|Cass 4.1.3 patched|
> |r8g.24xlarge|168k ops|496k ops (2.95x)|
> |r7i.24xlarge|153k ops|304k ops (1.98x)|
>
> Instructions to reproduce:
> {code:java}
> ## Requirements for Ubuntu 22.04
> sudo apt install -y ant git openjdk-11-jdk
> ## Build and run
> CASSANDRA_USE_JDK11=true ant realclean && CASSANDRA_USE_JDK11=true ant jar &&
> CASSANDRA_USE_JDK11=true ant stress-build && rm -rf data && bin/cassandra -f
> -R
> # Run
> bin/cqlsh -e 'drop table if exists keyspace1.standard1;' && \
> bin/cqlsh -e 'drop keyspace if exists keyspace1;' && \
> bin/nodetool clearsnapshot --all && tools/bin/cassandra-stress write
> n=10000000 cl=ONE -rate threads=384 -node 127.0.0.1 -log file=cload.log
> -graph file=cload.html && \
> bin/nodetool compact keyspace1 && sleep 30s && \
> tools/bin/cassandra-stress mixed ratio\(write=10,read=90\) duration=10m
> cl=ONE -rate threads=406 -node localhost -log file=result.log -graph
> file=graph.html
> {code}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
