perf test: Silence tracepoint event failures
Currently, when 'perf test' is run by a normal user, it'll fail to access tracepoint events. The output becomes somewhat messy because it tries to be nice with long error messages and hints. IMHO this is not needed for 'perf test' by default and AFAIK 'perf test' uses pr_debug() rather than pr_err() for such messages so that one can use -v option to see further details on failed testcases if needed. Before: $ perf test 1: vmlinux symtab matches kallsyms : FAILED! 2: detect openat syscall event :Error: No permissions to read /sys/kernel/debug/tracing/events/syscalls/sys_enter_openat Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' FAILED! 3: detect openat syscall event on all cpus :Error: No permissions to read /sys/kernel/debug/tracing/events/syscalls/sys_enter_openat Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' FAILED! ... After: $ perf test 1: vmlinux symtab matches kallsyms : FAILED! 2: detect openat syscall event : FAILED! 3: detect openat syscall event on all cpus : FAILED! ... $ perf test -v 2 2: detect openat syscall event : --- start --- test child forked, pid 30575 Error: No permissions to read /sys/kernel/debug/tracing/events/syscalls/sys_enter_openat Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' test child finished with -1 ---- end ---- detect openat syscall event: FAILED! Signed-off-by: NNamhyung Kim <namhyung@kernel.org> Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com> Acked-by: NDavid Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1445268229-1601-1-git-send-email-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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