Date: Mon, 4 May 2015 15:10:05 +0000 (UTC)
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Drew Richardson <drew.richardson@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>,
        linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        John Stultz <john.stultz@linaro.org>,
        Wade Cherry <wade.cherry@arm.com>
Message-ID: <199091314.42407.1430752205090.JavaMail.zimbra@efficios.com>
In-Reply-To: <1430750469-16428-1-git-send-email-drew.richardson@arm.com>
References: <1430750469-16428-1-git-send-email-drew.richardson@arm.com>
Subject: Re: [PATCH] ftrace: Provide trace clock monotonic raw
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Thread-Topic: ftrace: Provide trace clock monotonic raw
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----- Original Message -----
> Expose the NMI safe accessor to the monotonic raw clock to the
> tracer. The mono clock was added with commit
> 1b3e5c0936046e7e023149ddc8946d21c2ea20eb. Although the monotonic raw
> clock cannot be used to compare time between different machines, it is
> not perterbed by ntp.

perterbed -> perturbed

> 
> Signed-off-by: Drew Richardson <drew.richardson@arm.com>
>

What is the use-case that justify exposing the "raw fast"
clock that cannot be handled by the "monotonic fast" clock ?

Thanks,

Mathieu

> ---
>  kernel/trace/trace.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 05330494a0df..458031c31a37 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -876,6 +876,7 @@ static struct {
>  	{ trace_clock_jiffies,		"uptime",	0 },
>  	{ trace_clock,			"perf",		1 },
>  	{ ktime_get_mono_fast_ns,	"mono",		1 },
> +	{ ktime_get_raw_fast_ns,	"mono_raw",	1 },
>  	ARCH_TRACE_CLOCKS
>  };
>  
> --
> 2.1.4
> 
> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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