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From: Binoy Jayan <binoy.jayan@linaro.org>
To: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Cc: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	Daniel Wagner <daniel.wagner@bmw-carit.de>,
	Arnd Bergmann <arnd@arndb.de>,
	Linux kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 3/3] tracing: Histogram for missed timer offsets
Date: Fri, 2 Sep 2016 18:11:39 +0530	[thread overview]
Message-ID: <CAHv-k_9AP1k6baG6P3VRTcAGsP4GP3Vn7vvqCw+7b6ZFe9TM5w@mail.gmail.com> (raw)
In-Reply-To: <CAA93ih3k+f-gSMqbmU_TPBs7rzwy9gRDaGNh_ZNofw1H63N83g@mail.gmail.com>

On 30 August 2016 at 16:20, Masami Hiramatsu
<masami.hiramatsu@linaro.org> wrote:
> Hi Binoy,
>>
>> +static inline void trace_latency_hrtimer_mark_ts(struct hrtimer *timer,
>> +                                        struct hrtimer_clock_base *new_base,
>> +                                        ktime_t tim)
>> +{
>> +#if defined(CONFIG_PREEMPT_TRACER) || defined(CONFIG_IRQSOFF_TRACER)
>> +       if (trace_latency_hrtimer_interrupt_enabled()) {
>
> You would better use unlikely() here.
>
>> +               ktime_t now = new_base->get_time();
>> +
>> +               if (ktime_to_ns(tim) < ktime_to_ns(now))
>
> Wouldn't we need to consider the case of wrap around?
>
>> +                       timer->praecox = now;
>> +               else
>> +                       timer->praecox = ktime_set(0, 0);
>> +       }
>> +#endif
>> +}

Hi Masami,

I always see these values to be relative and not absolute time. I
found 'praecox' to be always zero during test.
What do you think.

Binoy

  reply	other threads:[~2016-09-02 12:41 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-30 10:28 [PATCH v4 0/3] *** Latency histograms - IRQSOFF,PREEMPTOFF *** Binoy Jayan
2016-08-30 10:28 ` [PATCH v4 1/3] tracing: Deference pointers without RCU checks Binoy Jayan
2016-08-30 10:28 ` [PATCH v4 2/3] tracing: Add trace_irqsoff tracepoints Binoy Jayan
2016-08-30 11:30   ` Daniel Wagner
2016-08-30 11:49     ` Binoy Jayan
2016-08-30 14:08   ` Steven Rostedt
2016-08-31 11:39     ` Binoy Jayan
2016-08-30 10:28 ` [PATCH v4 3/3] tracing: Histogram for missed timer offsets Binoy Jayan
2016-08-30 10:50   ` Masami Hiramatsu
2016-09-02 12:41     ` Binoy Jayan [this message]
2016-09-02 15:54       ` Masami Hiramatsu
2016-08-30 14:15   ` Steven Rostedt
2016-08-31 11:34     ` Binoy Jayan
2016-08-31 12:42       ` Steven Rostedt
2016-08-30 11:39 ` [PATCH v4 0/3] *** Latency histograms - IRQSOFF,PREEMPTOFF *** Daniel Wagner
2016-08-30 12:02   ` Masami Hiramatsu

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