Bug 2036658

Summary: [aarch64] - poor performance of trace-cmd record
Product: Red Hat Enterprise Linux 8 Reporter: Jiri Hladky <jhladky>
Component: trace-cmdAssignee: Jerome Marchand <jmarchan>
Status: CLOSED WONTFIX QA Contact: Kamil Kolakowski <kkolakow>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: ---CC: atomasov, jhladky, jkacur, jvozar, kkolakow
Target Milestone: rcKeywords: Triaged
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Hardware: aarch64   
OS: Unspecified   
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Last Closed: 2023-07-03 07:28:22 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Jiri Hladky 2022-01-03 14:11:44 UTC 
Description of problem:

Hello,

on the following aarch64 system https://beaker.engineering.redhat.com/view/armatura2.slevarna.tpb.lab.eng.brq.redhat.com#details

CPU(s):                 224
2x Cavium ThunderX2(R) CPU CN9975 v2.2 @ 2.0GHz
https://en.wikichip.org/wiki/cavium/thunderx2/cn9975

we observe the poor performance of the trace-cmd record command on RHEL-8. It's slower by factor 2.5x compared to RHEL-9:

RHEL-8.6.0-20211121.1 4.18.0-350.el8.aarch64 
$ time trace-cmd record --quiet -e sched:sched_move_numa sleep 0.1
real    0m26.354s
user    0m0.178s
sys     0m0.188s


RHEL-9.0.0-20211213.3 5.14.0-29.el9.aarch64
$ time trace-cmd record --quiet -e sched:sched_move_numa sleep 0.1
real    0m10.697s
user    0m0.418s
sys     0m0.324s


On x86_64, trace-cmd record performance on RHEL-8 is OK:
RHEL-8.6.0-20211121.1 4.18.0-350.el8.x86_64
128 CPUs
https://beaker.engineering.redhat.com/view/amd-epyc2-rome-7502-2s.lab.eng.brq.redhat.com#details
$ time trace-cmd record --quiet -e sched:sched_move_numa sleep 0.1
real    0m4.062s
user    0m0.028s
sys     0m0.214s


It seems that only aarch64 is affected. 

Could you please investigate the problem and check if we can reach the same performance of trace-cmd record as on RHEL-9? 

Thanks a lot!
Jirka
Comment 2 RHEL Program Management 2023-07-03 07:28:22 UTC 
After evaluating this issue, there are no plans to address it further or fix it in an upcoming release.  Therefore, it is being closed.  If plans change such that this issue will be fixed in an upcoming release, then the bug can be reopened.