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perf tools: Fixup exit path when not able to open events

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We have to deal with the TUI mode in perf top, so that we don't end up
with a garbled screen when, say, a non root user on a machine with a
paranoid setting (the default) tries to use 'perf top'.

Introduce a ui__warning_paranoid() routine shared by top and record that
tells the user the valid values for /proc/sys/kernel/perf_event_paranoid.

Cc: David Ahern <daahern@cisco.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2011-03-28 09:50:11 -03:00
commit c286c419c7
4 changed files with 39 additions and 19 deletions
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9
tools/perf/builtin-record.c
View file

@ -275,11 +275,10 @@ try_again:
!no_inherit) < 0) {
int err = errno;
if (err == EPERM || err == EACCES)
die("Permission error - are you root?\n"
"\t Consider tweaking"
" /proc/sys/kernel/perf_event_paranoid.\n");
else if (err == ENODEV && cpu_list) {
if (err == EPERM || err == EACCES) {
ui__warning_paranoid();
exit(EXIT_FAILURE);
} else if (err == ENODEV && cpu_list) {
die("No such device - did you specify"
" an out-of-range profile CPU?\n");
} else if (err == EINVAL && sample_id_all_avail) {

38
tools/perf/builtin-top.c
View file

@ -850,10 +850,10 @@ try_again:
top.evlist->threads, group, inherit) < 0) {
int err = errno;
if (err == EPERM || err == EACCES)
die("Permission error - are you root?\n"
"\t Consider tweaking"
" /proc/sys/kernel/perf_event_paranoid.\n");
if (err == EPERM || err == EACCES) {
ui__warning_paranoid();
goto out_err;
}
/*
* If it's cycles then fall back to hrtimer
* based cpu-clock-tick sw counter, which
@ -861,25 +861,35 @@ try_again:
*/
if (attr->type == PERF_TYPE_HARDWARE &&
attr->config == PERF_COUNT_HW_CPU_CYCLES) {
if (verbose)
warning(" ... trying to fall back to cpu-clock-ticks\n");
ui__warning("Cycles event not supported,\n"
"trying to fall back to cpu-clock-ticks\n");
attr->type = PERF_TYPE_SOFTWARE;
attr->config = PERF_COUNT_SW_CPU_CLOCK;
goto try_again;
}
printf("\n");
error("sys_perf_event_open() syscall returned with %d "
"(%s). /bin/dmesg may provide additional information.\n",
err, strerror(err));
die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
exit(-1);
ui__warning("The sys_perf_event_open() syscall "
"returned with %d (%s). /bin/dmesg "
"may provide additional information.\n"
"No CONFIG_PERF_EVENTS=y kernel support "
"configured?\n", err, strerror(err));
goto out_err;
}
}
if (perf_evlist__mmap(evlist, mmap_pages, false) < 0)
die("failed to mmap with %d (%s)\n", errno, strerror(errno));
if (perf_evlist__mmap(evlist, mmap_pages, false) < 0) {
ui__warning("Failed to mmap with %d (%s)\n",
errno, strerror(errno));
goto out_err;
}
return;
out_err:
exit_browser(0);
exit(0);
}
static int __cmd_top(void)

10
tools/perf/util/debug.c
View file

@ -57,6 +57,16 @@ void ui__warning(const char *format, ...)
}
#endif
void ui__warning_paranoid(void)
{
ui__warning("Permission error - are you root?\n"
"Consider tweaking /proc/sys/kernel/perf_event_paranoid:\n"
" -1 - Not paranoid at all\n"
" 0 - Disallow raw tracepoint access for unpriv\n"
" 1 - Disallow cpu events for unpriv\n"
" 2 - Disallow kernel profiling for unpriv\n");
}
void trace_event(union perf_event *event)
{
unsigned char *raw_event = (void *)event;

1
tools/perf/util/debug.h
View file

@ -36,5 +36,6 @@ int ui_helpline__show_help(const char *format, va_list ap);
#endif
void ui__warning(const char *format, ...) __attribute__((format(printf, 1, 2)));
void ui__warning_paranoid(void);
#endif /* __PERF_DEBUG_H */