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| author | David Sharp <dhsharp@google.com> | 2012-10-11 16:27:52 -0700 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2012-11-02 10:21:47 -0400 |
| commit | 60303ed3f4b9332b9aa9bc17c68bc174e7343e2d (patch) | |
| tree | 1d9a7c8001297aafda1e873884dd8bda5aaf7872 /kernel | |
| parent | 60efc15ae96c7aace8060411b0d5add20e1ab21e (diff) | |
| download | linux-60303ed3f4b9332b9aa9bc17c68bc174e7343e2d.tar.gz linux-60303ed3f4b9332b9aa9bc17c68bc174e7343e2d.tar.bz2 linux-60303ed3f4b9332b9aa9bc17c68bc174e7343e2d.zip | |
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
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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | 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 88111b08b2c1..6ed6013dff2b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4073,6 +4073,14 @@ 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; |