From 456ef4c11c06f0b8c53acaf796d77d2033f079f2 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 7 Dec 2020 14:04:05 -0300 Subject: [PATCH] perf evsel: Emit warning about kernel not supporting the data page size sample_type bit Before we had this unhelpful message: $ perf record --data-page-size sleep 1 Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles:u). /bin/dmesg | grep -i perf may provide additional information. $ Add support to the perf_missing_features variable to remember what caused evsel__open() to fail and then use that information in evsel__open_strerror(). $ perf record --data-page-size sleep 1 Error: Asking for the data page size isn't supported by this kernel. $ Cc: Kan Liang Cc: Namhyung Kim Cc: Andi Kleen Cc: Jiri Olsa Cc: Mark Rutland Cc: Michael Ellerman Cc: Stephane Eranian Cc: Will Deacon Link: http://lore.kernel.org/lkml/20201207170759.GB129853@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 9 ++++++++- tools/perf/util/evsel.h | 1 + 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 5e6085c3fc76..c26ea82220bd 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1873,7 +1873,12 @@ static int evsel__open_cpu(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.cgroup && evsel->core.attr.cgroup) { + if (!perf_missing_features.data_page_size && + (evsel->core.attr.sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)) { + perf_missing_features.data_page_size = true; + pr_debug2_peo("Kernel has no PERF_SAMPLE_DATA_PAGE_SIZE support, bailing out\n"); + goto out_close; + } else if (!perf_missing_features.cgroup && evsel->core.attr.cgroup) { perf_missing_features.cgroup = true; pr_debug2_peo("Kernel has no cgroup sampling support, bailing out\n"); goto out_close; @@ -2673,6 +2678,8 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, "We found oprofile daemon running, please stop it and try again."); break; case EINVAL: + if (evsel->core.attr.sample_type & PERF_SAMPLE_DATA_PAGE_SIZE && perf_missing_features.data_page_size) + return scnprintf(msg, size, "Asking for the data page size isn't supported by this kernel."); if (evsel->core.attr.write_backward && perf_missing_features.write_backward) return scnprintf(msg, size, "Reading from overwrite event is not supported by this kernel."); if (perf_missing_features.clockid) diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index 79a860d8e3ee..cd1d8dd43199 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -144,6 +144,7 @@ struct perf_missing_features { bool aux_output; bool branch_hw_idx; bool cgroup; + bool data_page_size; }; extern struct perf_missing_features perf_missing_features;