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perf parse-events: Make legacy events lower priority than sysfs/JSON
mainline inclusion from mainline-v6.8-rc1 commit a24d9d9dc096fc0d0bd85302c9a4fe4fe3b1107b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8BOB3 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a24d9d9dc096fc0d0bd85302c9a4fe4fe3b1107b -------------------------------- The perf tool has previously made legacy events the priority so with or without a PMU the legacy event would be opened: $ perf stat -e cpu-cycles,cpu/cpu-cycles/ true Using CPUID GenuineIntel-6-8D-1 intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch Attempting to add event pmu 'cpu' with 'cpu-cycles,' that may result in non-fatal errors After aliases, add event pmu 'cpu' with 'cpu-cycles,' that may result in non-fatal errors Control descriptor is not initialized ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 833967 cpu -1 group_fd -1 flags 0x8 = 3 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ ... Fixes to make hybrid/BIG.little PMUs behave correctly, ie as core PMUs capable of opening legacy events on each, removing hard coded "cpu_core" and "cpu_atom" Intel PMU names, etc. caused a behavioral difference on Apple/ARM due to latent issues in the PMU driver reported in: https://lore.kernel.org/lkml/08f1f185-e259-4014-9ca4-6411d5c1bc65@marcan.st/ As part of that report Mark Rutland <mark.rutland@arm.com> requested that legacy events not be higher in priority when a PMU is specified reversing what has until this change been perf's default behavior. With this change the above becomes: $ perf stat -e cpu-cycles,cpu/cpu-cycles/ true Using CPUID GenuineIntel-6-8D-1 Attempt to add: cpu/cpu-cycles=0/ ..after resolving event: cpu/event=0x3c/ Control descriptor is not initialized ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 827628 cpu -1 group_fd -1 flags 0x8 = 3 ------------------------------------------------------------ perf_event_attr: type 4 (PERF_TYPE_RAW) size 136 config 0x3c sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ ... So the second event has become a raw event as /sys/devices/cpu/events/cpu-cycles exists. A fix was necessary to config_term_pmu in parse-events.c as check_alias expansion needs to happen after config_term_pmu, and config_term_pmu may need calling a second time because of this. config_term_pmu is updated to not use the legacy event when the PMU has such a named event (either from JSON or sysfs). The bulk of this change is updating all of the parse-events test expectations so that if a sysfs/JSON event exists for a PMU the test doesn't fail - a further sign, if it were needed, that the legacy event priority was a known and tested behavior of the perf tool. Reported-by:Hector Martin <marcan@marcan.st> Signed-off-by: