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From: Thomas Richter <tmricht@linux.ibm.com>
To: "linux-perf-use." <linux-perf-users@vger.kernel.org>
Cc: Jan Polensky <japo@linux.ibm.com>
Subject: perf stat dumps core when CPU offline
Date: Wed, 3 Dec 2025 14:20:18 +0100	[thread overview]
Message-ID: <94313b82-888b-4f42-9fb0-4585f9e90080@linux.ibm.com> (raw)

Hi all,

Is this a known issue? Trying to do a perf stat on a CPU which is offline.

# echo 1 > /sys/devices/system/cpu/cpu1/online
# perf stat -C1 -e cycles -- true

 Performance counter stats for 'CPU(s) 1':

           123,965      cycles                                                                

       0.000356838 seconds time elapsed

# echo 0 > /sys/devices/system/cpu/cpu1/online
# perf stat -C1 -e cycles -- true
WARNING: A requested CPU in '1' is not supported by PMU 'cpum_cf' (CPUs 0,2-7) for event 'cycles'
Segmentation fault         (core dumped) perf stat -C1 -e cycles -- true
# 

This happens on linux-next and linux.

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

Vorsitzender des Aufsichtsrats: Wolfgang Wendt

Geschäftsführung: David Faller

Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294


             reply	other threads:[~2025-12-03 13:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-03 13:20 Thomas Richter [this message]
2025-12-03 17:47 ` perf stat dumps core when CPU offline Ian Rogers
2025-12-03 21:51   ` Ian Rogers

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