linux-kernel - Re: [PATCH 2/8] perf symbols: Move idle syms check from top to generic function

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Date:	Sat, 30 Nov 2013 08:58:56 -0700
From:	David Ahern <dsahern@...il.com>
To:	Namhyung Kim <namhyung@...nel.org>
CC:	acme@...stprotocols.net, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...nel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Jiri Olsa <jolsa@...hat.com>,
	Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH 2/8] perf symbols: Move idle syms check from top to generic
 function

On 11/28/13, 1:36 AM, Namhyung Kim wrote:
> Hi David,
>
> Just minor nits below..
>
> On Mon, 18 Nov 2013 13:32:45 -0700, David Ahern wrote:
>> Allows list of idle symbols to be leveraged by other commands,
>> such as the upcoming timehist command.
>
> [SNIP]
>> +bool symbol__is_idle(struct symbol *sym)
>> +{
>> +	const char * const idle_symbols[] = {
>
> Wouldn't it better making it static?  It seems to build a table
> everytime otherwise.

Checked a couple of gcc's (4.3.2 32-bit and 4.6.3 64-bit) and both put 
idle_symbols in read-only data section. e.g.,

0000000000000020 r idle_symbols.13404

So I think it is fine as is.

>
>
>> +		"cpu_idle",
>> +		"intel_idle",
>> +		"default_idle",
>> +		"native_safe_halt",
>> +		"enter_idle",
>> +		"exit_idle",
>> +		"mwait_idle",
>> +		"mwait_idle_with_hints",
>> +		"poll_idle",
>> +		"ppc64_runlatch_off",
>> +		"pseries_dedicated_idle_sleep",
>> +		NULL
>> +	};
>> +
>> +	int i;
>> +
>> +	if (!sym)
>> +		return false;
>> +
>> +	for (i = 0; idle_symbols[i]; i++) {
>
> Also we can use ARRAY_SIZE() here and let the last NULL go IMHO.

I copied what was in builtin-top.c.

David
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