With Linux and perf 4.15.0-55-generic (non-HWE), it works as reported in Ubuntu 18.04.3 LTS:
Versions -------- $ uname -r 4.15.0-55-generic $ perf --version perf version 4.15.18 In dpkg: ii linux-image-4.15.0-55-generic 4.15.0-55.60 amd64 Signed kernel image generic ii linux-tools-common 4.15.0-55.60 all Linux kernel version specific tools for version 4.15.0 ii linux-tools-4.15.0-55-generic 4.15.0-55.60 amd64 Linux kernel version specific tools for version 4.15.0-55 A minimal series of steps necessary to make it happen ----------------------------------------------------- 1. In a terminal tab., run: $ top 2. In another tab, run $ perf top -p `pidof top` 3. Look at the output of "perf top". What you expected to happen --------------------------- I expect to see "cycles" events being reported for the process "top" (started at step 1.) What actually happened ---------------------- I see this, so it works: Samples: 136 of event 'cycles:ppp', Event count (approx.): 54426558 Overhead Shared Object Symbol 8.48% libc-2.27.so [.] _IO_vfscanf 6.49% [kernel] [k] do_syscall_64 4.06% [kernel] [k] pid_revalidate 3.50% [kernel] [k] syscall_return_via_sysret 3.05% [kernel] [k] vsnprintf 2.90% [kernel] [k] get_pid_task 2.88% [kernel] [k] seq_put_decimal_ull 2.75% [kernel] [k] __task_pid_nr_ns 2.74% [kernel] [k] seq_put_decimal_ll 2.71% libc-2.27.so [.] __GI_____strtoull_l_internal 2.41% [kernel] [k] format_decode 2.38% [kernel] [k] memcpy_erms 2.18% libc-2.27.so [.] vfprintf 1.93% [kernel] [k] pid_nr_ns 1.79% [kernel] [k] __d_lookup_rcu 1.63% [kernel] [k] rcu_all_qs 1.58% [kernel] [k] filldir 1.39% [kernel] [k] render_sigset_t System calls ------------ perf_event_open System calls: $ strace perf top -p `pidof top` 2>&1 | grep ^perf_event_open perf_event_open({type=PERF_TYPE_HARDWARE, size=PERF_ATTR_SIZE_VER5, config=PERF_COUNT_HW_CPU_CYCLES, ...}, 0, -1, -1, 0) = 3 perf_event_open({type=PERF_TYPE_SOFTWARE, size=0 /* PERF_ATTR_SIZE_??? */, config=PERF_COUNT_SW_CPU_CLOCK, ...}, -1, 6, -1, PERF_FLAG_FD_CLOEXEC) = 3 perf_event_open({type=PERF_TYPE_HARDWARE, size=PERF_ATTR_SIZE_VER5, config=PERF_COUNT_HW_CPU_CYCLES, ...}, -1, 0, -1, PERF_FLAG_FD_CLOEXEC) = 3 perf_event_open({type=PERF_TYPE_HARDWARE, size=PERF_ATTR_SIZE_VER5, config=PERF_COUNT_HW_CPU_CYCLES, ...}, -1, 0, -1, PERF_FLAG_FD_CLOEXEC) = 3 perf_event_open({type=PERF_TYPE_HARDWARE, size=PERF_ATTR_SIZE_VER5, config=PERF_COUNT_HW_CPU_CYCLES, ...}, 12089, -1, -1, PERF_FLAG_FD_CLOEXEC) = 3 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1839852 Title: perf broken on hwe kernel 5.0.0-23 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-hwe/+bug/1839852/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs