Quoting John Ettedgui at 2015-07-30-21:10:27(-0700): > On Thu, Jul 30, 2015 at 7:34 PM, Qu Wenruo <quwenruo@xxxxxxxxxxxxxx> wrote: > > > > Hi John, > > Thanks for the trace output. > You are welcome, thank you for looking at it! > > > > But it seems that, your root partition is also btrfs, causing a lot of btrfs > > trace from your systemd journal. > > > Oh yes sorry about that. > I actually have 3 partition in btrfs, the problematic one being the > only big one. > > Would you mind re-collecting the ftrace without such logging system caused > > btrfs trace? > Sure, how would I do that? > This is my first time using ftrace. > > > > BTW, although I'm not quite familiar with ftrace, would you please consider > > collect ftrace with function_graph tracer? > Sure, how would I do that one as well? You can use set_ftrace_pid to trace only a single process (for example, the mount command). There is a sample script I found in the ftrace documentation that goes something like this: # First disable tracing, to clear the trace buffer echo nop > current_tracer echo 0 > tracing_on echo 0 > tracing_enabled # Then re-enable it after setting the filters echo $$ > set_ftrace_pid echo '*btrfs*' > set_ftrace_filter echo function_graph > current_tracer echo 1 > tracing_enabled echo 1 > tracing_on # And finally *exec* the command to trace: exec mount .... I tried it, but the logs were way too large, and I was still fiddling with the trace_options to set. If someone has good advice, we can try it again -- Georgi -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
