Re: [PATCH 2/2] tracing/fastboot: Use the ring-buffer timestamp for initcall entries

From: Frédéric Weisbecker
Date: Wed Nov 12 2008 - 05:58:37 EST


2008/11/12 Ingo Molnar <mingo@xxxxxxx>:
>
> * Frederic Weisbecker <fweisbec@xxxxxxxxx> 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@xxxxxxxxx>
>> ---
>> 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)
>
> Ingo
>


Yes. I'm using the default formatting output in trace.c so perhaps
there is some iter flag I should dynamically remove
from the boot tracer to avoid that or perhaps I may format a custom
output for sched entries for the boot tracer.
I will see that....

By the way Arjan, does the actual state of the boot tracer match your needs?
You can find an example of its trace here:
http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commit;h=74239072830ef3f1398edeb1bc1076fc330fd4a2
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