The fix landed in focal master with 'Ubuntu-5.4.0-43.47' and we are as
of today at '5.4.0.45.49' in focal-updates, hence updating the focal
entry of this ticket to Fix Released.
** Changed in: linux (Ubuntu)
Status: Fix Committed => Fix Released
** Changed in: ubuntu-z-systems
Status: Fix Committed => Fix Released
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https://bugs.launchpad.net/bugs/1881096
Title:
[UBUNTU 20.04] Deflate counters reported by lscpumf are not valid or
available with perf
Status in Ubuntu on IBM z Systems:
Fix Released
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Focal:
Fix Released
Bug description:
SRU Justification:
==================
[Impact]
* With perf from Ubuntu 20.04 on IBM z15 hardware, some counters
reported with lscpumf are not usable with 'perf stat -e'.
* 'lscpumf -c' provides a list of available counters, but the
following are not usable: DFLT_ACCESS, DFLT_CYCLES, DFLT_CC,
DFLT_CCERROR
* 'perf list' is also not offering these counters.
* On the kernel side this is fixed with the following upstream
accepted commit:
[Fix]
* d68d5d51dc898895b4e15bea52e5668ca9e76180 d68d5d51dc898895b
"s390/cpum_cf: Add new extended counters for IBM z15"
[Test Case]
* Requires the fix/patch of the perf tool, as mentioned in the bug,
too.
* An IBM z15 (or LinuxONE III) system with Ubuntu 20.04 installed in
LPAR is needed where the counters are enabled in the activation
profile.
* Use 'perf list' to determine if the counters DFLT_ACCESS,
DFLT_CYCLES, DFLT_CC, DFLT_CCERROR are listed
* Use 'perf stat -e' to enable amd make use of these counters.
[Regression Potential]
* The regression can be considered as low, since:
* it's architecture specific (s390x)
* limited to IBM z15 hardware
* and only additional (s390x) hardware counters are defined and added.
[Other]
* This requires a patch to be included into the perf itself, too -
please see bug description for more details.
* Since this patch is upstream in kernel 5.7 it will automatically
land in groovy.
__________
---Problem Description---
ubuntu 20.04: perf on z15: some counters reported with lscpumf are not usable
with perf stat -e
---uname output---
Linux ubu204 5.4.0-26-generic #30-Ubuntu SMP Mon Apr 20 16:57:22 UTC 2020
s390x s390x s390x GNU/Linux
Machine Type = z15 8561
---Steps to Reproduce---
lscpumf -c gives a list of available counters, but a few of them are not
usable: DFLT_ACCESS,DFLT_CYCLES,DFLT_CC,DFLT_CCERROR
perf list is also not offering these counters.
A solution will be a backport to 20.04, and tried to made available
for next SRU , code needed before 06-12.
Addl Info from Dev:
I have downloaded the following repository
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal
and checked out branch master-next.
Both patches appended apply without warning and the compilation showed
no error.
For the perf tool:
e7950166e40271c02 perf vendor events s390: Add new deflate counters for IBM
z15
For the s390 kernel
d68d5d51dc898895b s390/cpum_cf: Add new extended counters for IBM z15
All accepted for kernel 5.7 rc1
Please include both patches into Ubuntu 20.04
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