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From: Ingo Molnar <mingo@kernel.org>
To: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Jiri Olsa <jolsa@redhat.com>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Subject: Re: [PATCH] perf tool: report user-friendly error from timechart
Date: Thu, 3 Oct 2013 14:38:21 +0200	[thread overview]
Message-ID: <20131003123820.GA12004@gmail.com> (raw)
In-Reply-To: <1380791146-7465-1-git-send-email-artagnon@gmail.com>


* Ramkumar Ramachandra <artagnon@gmail.com> wrote:

> +	/* Perform a quick sanity check */
> +	if (!is_valid_tracepoint("power:cpu_frequency")) {
> +		fprintf(stderr, "Error:\tNo permissions to read $debugfs/tracing/events/power/cpu_frequency\n");
> +		fprintf(stderr, "Hint:\tChange the permissions of debugfs: /sys/kernel/debug\n");
> +		fprintf(stderr, "\tThe directory will be present if your kernel was compiled with debugfs support.\n");

Is missing permissions the only way how is_valid_tracepoint() can fail?

What if debugfs has the right permissions but CONFIG_TRACEPOINTS is 
disabled in the kernel?

Thanks,

	Ingo

  reply	other threads:[~2013-10-03 12:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-03  9:05 [PATCH] perf tool: report user-friendly error from timechart Ramkumar Ramachandra
2013-10-03 12:38 ` Ingo Molnar [this message]
2013-10-03 12:43   ` Ramkumar Ramachandra
2013-10-03 13:09     ` Ingo Molnar
2013-10-03 13:35   ` David Ahern
2013-10-03 17:08     ` Arnaldo Carvalho de Melo
2013-10-03 17:22       ` David Ahern

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