[PATCH v6 2/6] 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 Cc: Steven Rostedt Cc: Masami Hiramatsu --- 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(_trace); + if (max_tr.buffer) + tracing_reset_online_cpus(_tr); + mutex_unlock(_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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v6 2/6] 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 dhsh...@google.com Cc: Steven Rostedt rost...@goodmis.org Cc: Masami Hiramatsu masami.hiramatsu...@hitachi.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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
