[linux-next] perf report runtime extremely long

[Thomas Richter <tmricht@linux.ibm.com>]

Hi all,

has something changed recently in perf report in linux-next repo?

I run perf report -i <file> -D | grep something
on s390 with 2 different kernels:

master 6.18.0rc3:
# uname -a
Linux a35lp67.lnxne.boe 6.18.0-rc3m-perf+ #23 SMP Tue Oct 28 15:53:44 CET 2025 s390x GNU/Linux
# ll /tmp/perf2-eSso2q-2
-rw------- 1 root root 8538184 Oct 29 08:44 /tmp/perf2-eSso2q-2
# time perf report -i/tmp/perf2-eSso2q-2 -D | grep Counter:000 > /dev/null

real	0m22.262s
user	0m22.068s
sys	0m0.200s
# 

This runtime is ok for the perf.data file size.

linux-next:
# uname -a
Linux s83lp47.lnxne.boe 6.18.0-20251028.rc3.git141.f7d2388eeec2.63.fc42.s390x+next #1 SMP Tue Oct 28 20:06:13 CET 2025 s390x GNU/Linux
#ll /tmp/perf2-eSso2q-2
-rw-------. 1 root root 8538184 Oct 29 08:47 /tmp/perf2-eSso2q-2
# time perf report -i/tmp/perf2-eSso2q-2 -D | grep Counter:000 > /dev/null

real	2m53.601s
user	2m52.938s
sys	0m0.575s
#

Same perf.data file and run time increased from 22 seconds to nearly 300 seconds, roughly 14 times longer
for the same input!

Has anybody similar observations?

Thanks a lot

-- 
Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany
--
IBM Deutschland Research & Development GmbH

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