Messages in this thread | | | Date | Wed, 12 Nov 2008 14:01:22 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 2/2] tracing/fastboot: Use the ring-buffer timestamp for initcall entries |
| |
* Steven Rostedt <rostedt@goodmis.org> wrote:
> > On Wed, 12 Nov 2008, Ingo Molnar wrote: > > > > > * Frederic Weisbecker <fweisbec@gmail.com> wrote: > > > > > Impact: Split the boot tracer entries in two parts: call and return > > > > > > Now that we are using the sched tracer from the boot tracer, we want > > > to use the same timestamp than the ring-buffer to have consistent > > > time captures between sched events and initcall events. So we get > > > rid of the old time capture by the boot tracer and split the > > > initcall events in two parts: call and return. This way we have the > > > ring buffer timestamp of both. > > > > > > There is an example of a trace in attachment. > > > > > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > > > --- > > > include/trace/boot.h | 31 ++++++++--- > > > init/main.c | 32 ++++++------ > > > kernel/trace/trace.h | 17 ++++-- > > > kernel/trace/trace_boot.c | 123 ++++++++++++++++++++++++++++++++++----------- > > > 4 files changed, 144 insertions(+), 59 deletions(-) > > > > applied to tip/tracing/fastboot, thanks Frederic! > > > > one small detail, do we need these messages in the boot tracer: > > > > ##### CPU 1 buffer started #### > > > > they are helpful for latency traces but might be confusing for boot > > traces. (they lose their attraction after having seen a dozen of them) > > Yeah, I was thinking of putting in a iter_ctrl to disable them. But > then, should they be on or off by default? > > The pro for having them off by default, they are not as distracting. > > The con for having them off by default, they lose their meaning, and > developers get confused when they see CPU 1 starting after 100 > prints of CPU0, when they both should have started.
i think they are useful to be included for most of the tracers, except the boot tracer (which starts/stop with high frequency). So i'd suggest to keep the default, but also to expose it in an iter_ctl plus dynamically turn it off for the boot tracer.
Ingo
| |