Messages in this thread Patch in this message |  | | Date | Fri, 02 Nov 2012 09:33:05 -0400 | | From | Steven Rostedt <> | | Subject | [PATCH 13/22] tracing: Reset ring buffer when changing trace_clocks |
| |
From: David Sharp <dhsharp@google.com>
Because the "tsc" clock isn't in nanoseconds, the ring buffer must be reset when changing clocks so that incomparable timestamps don't end up in the same trace.
Tested: Confirmed switching clocks resets the trace buffer.
Google-Bug-Id: 6980623 Link: http://lkml.kernel.org/r/1349998076-15495-3-git-send-email-dhsharp@google.com
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: David Sharp <dhsharp@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/trace/trace.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d7d6c52..d598ede 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4074,6 +4074,14 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, if (max_tr.buffer) ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func); + /* + * New clock may not be consistent with the previous clock. + * Reset the buffer so that it doesn't have incomparable timestamps. + */ + tracing_reset_online_cpus(&global_trace); + if (max_tr.buffer) + tracing_reset_online_cpus(&max_tr); + mutex_unlock(&trace_types_lock); *fpos += cnt; -- 1.7.10.4
[unhandled content-type:application/pgp-signature] |  |