From acb9f2d4755a70e31343f99791aa43b05401b996 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 13 Aug 2019 11:06:38 -0300 Subject: [PATCH] perf evsel: Provide meaningful warning when trying to use 'aux_output' on older kernels Just like we do with the 'write_backwards' feature: Before: # perf record -e {intel_pt/branch=0/,cycles/aux-output/ppp} uname Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles/aux-output/ppp). /bin/dmesg | grep -i perf may provide additional information. # After: # perf record -e {intel_pt/branch=0/,cycles/aux-output/ppp} uname Error: The 'aux_output' feature is not supported, update the kernel. # Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lkml.kernel.org/n/tip-wgjsjroe1e150c0metgwmqwd@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 11 +++++++++-- tools/perf/util/evsel.h | 1 + 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 5da40511546b..0a33f7322ecc 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1738,7 +1738,8 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus, int pid = -1, err; enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE; - if (perf_missing_features.write_backward && evsel->core.attr.write_backward) + if ((perf_missing_features.write_backward && evsel->core.attr.write_backward) || + (perf_missing_features.aux_output && evsel->core.attr.aux_output)) return -EINVAL; if (cpus == NULL) { @@ -1912,7 +1913,11 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus, * Must probe features in the order they were added to the * perf_event_attr interface. */ - if (!perf_missing_features.bpf_event && evsel->core.attr.bpf_event) { + if (!perf_missing_features.aux_output && evsel->core.attr.aux_output) { + perf_missing_features.aux_output = true; + pr_debug2("Kernel has no attr.aux_output support, bailing out\n"); + goto out_close; + } else if (!perf_missing_features.bpf_event && evsel->core.attr.bpf_event) { perf_missing_features.bpf_event = true; pr_debug2("switching off bpf_event\n"); goto fallback_missing_features; @@ -2926,6 +2931,8 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target, return scnprintf(msg, size, "clockid feature not supported."); if (perf_missing_features.clockid_wrong) return scnprintf(msg, size, "wrong clockid (%d).", clockid); + if (perf_missing_features.aux_output) + return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel."); break; default: break; diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index 8a316dd54cd0..9cd6e3ae479a 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -184,6 +184,7 @@ struct perf_missing_features { bool group_read; bool ksymbol; bool bpf_event; + bool aux_output; }; extern struct perf_missing_features perf_missing_features;