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Message-Id: <1348004227-23575-2-git-send-email-dhsharp@google.com> Date: Tue, 18 Sep 2012 14:37:06 -0700 From: David Sharp <dhsharp@...gle.com> To: linux-kernel@...r.kernel.org Cc: David Sharp <dhsharp@...gle.com>, Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> Subject: [PATCH v2 2/3] tracing: reset ring buffer when changing trace_clocks 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 Signed-off-by: David Sharp <dhsharp@...gle.com> Cc: Steven Rostedt <rostedt@...dmis.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> --- kernel/trace/trace.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 92fb08e..4e26df3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4012,6 +4012,14 @@ 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; -- 1.7.7.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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