Messages in this thread | | | Date | Fri, 10 Feb 2017 09:19:21 -0500 | From | Steven Rostedt <> | Subject | Re: timers: Make flags output in the timer_start tracepoint useful |
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On Fri, 10 Feb 2017 14:25:03 +0100 (CET) Thomas Gleixner <tglx@linutronix.de> wrote:
> The timer flags in the timer_start trace event contain lots of useful > information, but the meaning is not clear in the trace output because its > just printed as a hex value. Making tools rely on the bit positions is bad > as they might change over time. > > Decode the flags in the printout. Tools can retrieve the bits and their > meaning from the trace format file. > > Example output: > kworker/2:1-47 <SNIP> [timeout=592] cpu=2 idx=170 flags=D|I > > So the timer is Deferrable and Interruptsafe, queued on CPU 2 into bucket > 170. > > Requested-by: Arjan van de Ven <arjan@linux.intel.com> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > include/trace/events/timer.h | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > --- a/include/trace/events/timer.h > +++ b/include/trace/events/timer.h > @@ -36,6 +36,13 @@ DEFINE_EVENT(timer_class, timer_init, > TP_ARGS(timer) > ); > > +#define decode_timer_flags(flags) \ > + __print_flags(flags, "|", \ > + { TIMER_MIGRATING, "M" }, \ > + { TIMER_DEFERRABLE, "D" }, \ > + { TIMER_PINNED, "P" }, \ > + { TIMER_IRQSAFE, "I" }) > + > /** > * timer_start - called when the timer is started > * @timer: pointer to struct timer_list > @@ -65,9 +72,12 @@ TRACE_EVENT(timer_start, > __entry->flags = flags; > ), > > - TP_printk("timer=%p function=%pf expires=%lu [timeout=%ld] flags=0x%08x", > + TP_printk("timer=%p function=%pf expires=%lu [timeout=%ld] cpu=%u idx=%u flags=%s", > __entry->timer, __entry->function, __entry->expires, > - (long)__entry->expires - __entry->now, __entry->flags) > + (long)__entry->expires - __entry->now, > + __entry->flags & TIMER_CPUMASK, > + __entry->flags >> TIMER_ARRAYSHIFT, > + decode_timer_flags(__entry->flags & TIMER_TRACE_FLAGMASK))
Hi Thomas,
This all looks good, but I can't find TIMER_TRACE_FLAGMASK. Was that added by another patch?
-- Steve
> ); > > /**
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