Messages in this thread Patch in this message | | | Date | Wed, 5 Feb 2020 10:49:43 -0500 | From | Joel Fernandes <> | Subject | Re: [PATCH v1 1/1] binder: transaction latency tracking for user build |
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On Wed, Feb 05, 2020 at 09:36:12AM +0000, Greg Kroah-Hartman wrote: > On Wed, Feb 05, 2020 at 02:52:52PM +0800, Frankie Chang wrote: > > Record start/end timestamp to binder transaction. > > When transaction is completed or transaction is free, > > it would be checked if transaction latency over threshold (2 sec), > > if yes, printing related information for tracing. > > > > Signed-off-by: Frankie Chang <Frankie.Chang@mediatek.com> > > --- > > drivers/android/Kconfig | 8 +++ > > drivers/android/binder.c | 107 +++++++++++++++++++++++++++++++++++++ > > drivers/android/binder_internal.h | 4 ++ > > 3 files changed, 119 insertions(+) > > > > diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig > > index 6fdf2ab..7ba80eb 100644 > > --- a/drivers/android/Kconfig > > +++ b/drivers/android/Kconfig > > @@ -54,6 +54,14 @@ config ANDROID_BINDER_IPC_SELFTEST > > exhaustively with combinations of various buffer sizes and > > alignments. > > > > +config BINDER_USER_TRACKING > > + bool "Android Binder transaction tracking" > > + help > > + Used for track abnormal binder transaction which is over 2 seconds, > > + when the transaction is done or be free, this transaction would be > > + checked whether it executed overtime. > > + If yes, printing out the detail info about it. > > + > > endif # if ANDROID > > > > endmenu > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > > index e9bc9fc..5a352ee 100644 > > --- a/drivers/android/binder.c > > +++ b/drivers/android/binder.c > > @@ -76,6 +76,11 @@ > > #include "binder_internal.h" > > #include "binder_trace.h" > > > > +#ifdef CONFIG_BINDER_USER_TRACKING > > +#include <linux/rtc.h> > > +#include <linux/time.h> > > +#endif > > + > > static HLIST_HEAD(binder_deferred_list); > > static DEFINE_MUTEX(binder_deferred_lock); > > > > @@ -591,8 +596,104 @@ struct binder_transaction { > > * during thread teardown > > */ > > spinlock_t lock; > > +#ifdef CONFIG_BINDER_USER_TRACKING > > + struct timespec timestamp; > > + struct timeval tv; > > +#endif > > }; > > > > +#ifdef CONFIG_BINDER_USER_TRACKING > > + > > +/* > > + * binder_print_delay - Output info of a delay transaction > > + * @t: pointer to the over-time transaction > > + */ > > +static void binder_print_delay(struct binder_transaction *t) > > +{ > > + struct rtc_time tm; > > + struct timespec *startime; > > + struct timespec cur, sub_t; > > + > > + ktime_get_ts(&cur); > > + startime = &t->timestamp; > > + sub_t = timespec_sub(cur, *startime); > > + > > + /* if transaction time is over than 2 sec, > > + * show timeout warning log. > > + */ > > + if (sub_t.tv_sec < 2) > > + return; > > + > > + rtc_time_to_tm(t->tv.tv_sec, &tm); > > + > > + spin_lock(&t->lock); > > + pr_info_ratelimited("%d: from %d:%d to %d:%d", > > + t->debug_id, > > + t->from ? t->from->proc->pid : 0, > > + t->from ? t->from->pid : 0, > > + t->to_proc ? t->to_proc->pid : 0, > > + t->to_thread ? t->to_thread->pid : 0); > > + spin_unlock(&t->lock); > > + > > + pr_info_ratelimited(" total %u.%03ld s code %u start %lu.%03ld android %d-%02d-%02d %02d:%02d:%02d.%03lu\n", > > + (unsigned int)sub_t.tv_sec, > > + (sub_t.tv_nsec / NSEC_PER_MSEC), > > + t->code, > > + (unsigned long)startime->tv_sec, > > + (startime->tv_nsec / NSEC_PER_MSEC), > > + (tm.tm_year + 1900), (tm.tm_mon + 1), tm.tm_mday, > > + tm.tm_hour, tm.tm_min, tm.tm_sec, > > + (unsigned long)(t->tv.tv_usec / USEC_PER_MSEC)); > > +} > > Ick, why not use a tracepoint for this instead? > > And what is userspace supposed to do with this if they see it?
Or another option is to implement this separately outside of binder.c using register_trace_* on the existing binder tracepoints, similar to what say the block tracer or preempt-off tracers do. Call it, say, "binder-latency tracer".
That way all of this tracing code is in-kernel but outside of binder.c.
thanks,
- Joel
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