Re: [tip:timers/tracing] hrtimer: Add tracepoint for hrtimers

From: Peter Zijlstra
Date: Tue Oct 13 2009 - 03:49:50 EST


On Mon, 2009-10-12 at 23:25 -0400, Steven Rostedt wrote:
> > + TP_printk("hrtimer %p, func %pf, expires %llu, softexpires %llu",
> > + __entry->timer, __entry->function,
> > + (unsigned long long)ktime_to_ns((ktime_t) {
> > + .tv64 = __entry->expires }),
> > + (unsigned long long)ktime_to_ns((ktime_t) {
> > + .tv64 = __entry->softexpires }))
> > +);
> > +
>
> I was just fixing up the trace-cmd parser (which is also used for perf)
> and came across this code. That TP_printk shows up in the format file
> as:
>
> print fmt: "hrtimer %p, func %pf, expires %llu, softexpires %llu", REC->timer, REC->function, (unsigned long long)(((ktime_t) { .tv64 = REC->expires }).tv64), (unsigned long long)(((ktime_t) { .tv64 = REC->softexpires }).tv64)
>
> Now I'm trying to parse this with a tool so that we can have something
> that can read the binary output, and be able to easily figure it out by
> reading the format files. But trying to parse:
>
> (unsigned long long)(((ktime_t) { .tv64 = REC->expires }).tv64)
>
> Is not easy. It's basically implementing a C interpreter :-(
>
> Is there anyway we can change that TRACE_EVENT to give us a better,
> trace printk output?

LOL

Either convince tglx that ktime_t really ought to die for good (yeah, I
know arm), or specialize the whole printout for 32 vs 64 ktime_t.

union ktime {
s64 tv64;
#if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
struct {
# ifdef __BIG_ENDIAN
s32 sec, nsec;
# else
s32 nsec, sec;
# endif
} tv;
#endif
};


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