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Mark Rutland
66ec11919a
Currently, perf record is broken on arm/arm64 systems when the PMU is specified explicitly as part of the event, e.g. $ ./perf record -e armv8_cortex_a53/cpu_cycles/u true In such cases, perf record fails to open events unless perf_event_paranoid is set to -1, even if the PMU in question supports mode exclusion. Further, even when perf_event_paranoid is toggled, no samples are recorded. This is an unintended side effect of commit:e3ba76deef("perf tools: Force uncore events to system wide monitoring) ... which assumes that if a PMU has an associated cpu_map, it is an uncore PMU, and forces events for such PMUs to be system-wide. This is not true for arm/arm64 systems, which can have heterogeneous CPUs. To account for this, multiple CPU PMUs are exposed, each with a "cpus" field under sysfs, which the perf tool parses into a cpu_map. ARM PMUs do not have a "cpumask" file, and only have a "cpus" file. For the gory details as to why, see commit:7e3fcffe95("perf pmu: Support alternative sysfs cpumask") Given all of this, we can instead identify uncore PMUs by explicitly checking for a "cpumask" file, and restore arm/arm64 PMU support back to a working state. This patch does so, adding a new perf_pmu::is_uncore field, and splitting the existing cpumask parsing so that it can be reused. Signed-off-by: Mark Rutland <[email protected]> Tested-by Will Deacon <[email protected]> Acked-by: Jiri Olsa <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: David Ahern <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: 4.12+ <[email protected]> Fixes:e3ba76deef("perf tools: Force uncore events to system wide monitoring) Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>