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Dipietro Salvatore commented on CASSANDRA-19429: ------------------------------------------------ > But yeah ... I am not running this on r8g.24xlarge or r7i.24xlarge . Not sure what is your HW but, based on our tests, the benefit of removing this lock starts using 4xlarge instance and above with ~1.40x improvement (tested on r7g.4xl and r7i.4xl). On small instances like r7i.xlarge, not a significant different has been recorded. > [~dipiets] I think the mistake you do is that you do "nodetool compact" after >you write the data and then you run mixed workload against that. Not sure I have got this completely. Why the "nodetool compact" has such huge difference with the patch and not with the released version? I see that it uses 1 SSTable but why does not have similar performance if this is the problem? I am testing the patch as you suggesting > 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, > asprof_cass4.1.3__lock_20240216052912lock.html > > Time Spent: 20m > 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: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org