** Changed in: linux (Ubuntu Bionic) Importance: Undecided => Medium ** Changed in: linux (Ubuntu Focal) Importance: Undecided => Medium
** Changed in: linux (Ubuntu Groovy) Importance: Undecided => Medium -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1891454 Title: [UBUNTU 20.04] kernel: s390/cpum_cf,perf: changeDFLT_CCERROR counter name Status in Ubuntu on IBM z Systems: In Progress Status in linux package in Ubuntu: Fix Committed Status in linux source package in Bionic: In Progress Status in linux source package in Focal: Fix Committed Status in linux source package in Groovy: Fix Committed Bug description: SRU Justification: ================== [Impact] * Change the counter name DLFT_CCERROR to DLFT_CCFINISH on IBM z15 to avoid confusion. * This counter counts completed DEFLATE instructions with exit code 0, 1 or 2. * And since exit code 0 means success and exit code 1 or 2 indicate errors the name can be ambiguous. [Fix] * Rename s390 z15 counter named DFLT_CCERROR to DFLT_CCFINISH. * Backport Focal: https://launchpadlibrarian.net/493272507/0001-s390 -cpum_cf-perf-change-DFLT_CCERROR-counter-name.patch * Backport Bionic: https://launchpadlibrarian.net/493439681/u18-0001-s390-cpum_cf-Add- new-extended-counters-for-IBM-z15.patch [Test Case] * Enable hardware counters in the activation profile of a z15 LPAR. * Just check the countername in sysfs with: ls /sys/devices/cpum_cf/events/{DFLT_CCERROR,DFLT_CCFINISH} [Regression Potential] * The regression potential can be considered as low, since: * Counters like these are usually not activated by default and need to be explicitly enabled. * No code functionality is changed with that patch, only a renaming is done at 3 places in one code file arch/s390/kernel/perf_cpum_cf_events.c as well as in /tools/perf/pmu- events/arch/s390/cf_z15/extended.json. * The fix got already upstream accepted in 5.8-rc7, hence it got upstream reviewed, * and the modifications are limited to s390x, are only relevant for the z15 / LinuxONE III hw generation that are relatively new. * Issue with the renaming I can think of are that people don't know about the new name and may look for the old one and don't find it anymore, * and with that also if the old counter name is used in scripts or applications, these may fails due to an unknown counter name. [Other Info] * The backports are based on commit 3d3af181d370069861a3be94608464e2ff3682e2 ("s390/cpum_cf,perf: change DFLT_CCERROR counter name") that is upstream accepted since v5.8-rc7. * Hence this SRU is not requested for groovy, since it's already in groovys kernel 5.8 in proposed, but only requested for focal and bionic. __________ Description: kernel: s390/cpum_cf,perf: change DFLT_CCERROR counter name Symptom: Counter name CCERROR is misleading. Problem: Change the counter name DLFT_CCERROR to DLFT_CCFINISH on IBM z15. This counter counts completed DEFLATE instructions with exit code 0, 1 or 2. Since exit code 0 means success and exit code 1 or 2 indicate errors, change the counter name to avoid confusion. This counter is incremented each time the DEFLATE instruction completed regardless if an error was detected or not. Solution: Rename s390 z15 counter named DFLT_CCERROR to DFLT_CCFINISH Reproduction: Command # ls /sys/devices/cpum_cf/events/DFLT_CCERROR currently succeeds. After this patch has been applied the command does not work anymore. The file does not exist anymore. Use command # ls /sys/devices/cpum_cf/events/DFLT_CCFINISH instead. Upstream-ID: 5ce1a24dd98c00a57a8fa13660648abf7e08e3ef Component: kernel 5.8 Will be integrated into 20.10 by kernel 5.8 integration. Backport available for 20.04. To be checked for 18.04 and 16.04, update will be provided Here is the backported patch. The upstream commit id is 3d3af181d370069861a3be94608464e2ff3682e2 ("s390/cpum_cf,perf: change DFLT_CCERROR counter name") To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1891454/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
