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Date:   Thu, 14 Jan 2021 15:42:56 +0800
From:   Leo Yan <leo.yan@linaro.org>
To:     Joe Perches <joe@perches.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Joe Mario <jmario@redhat.com>, David Ahern <dsahern@gmail.com>,
        Don Zickus <dzickus@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/5] perf c2c: Refactor display filter
Message-ID: <20210114074256.GA189511@leoy-ThinkPad-X240s>
References: <20210114033939.164538-1-leo.yan@linaro.org>
 <20210114033939.164538-4-leo.yan@linaro.org>
 <07e9ed776de833ab89fafdb76164e038e47f6d7c.camel@perches.com>
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Hi Joe,

On Wed, Jan 13, 2021 at 11:35:23PM -0800, Joe Perches wrote:
> On Thu, 2021-01-14 at 11:39 +0800, Leo Yan wrote:
> > When sort on the respective metrics (lcl_hitm, rmt_hitm, tot_hitm),
> > macro FILTER_HITM is to filter out the cache line entries if its
> > overhead is less than 1%.
> > 
> > This patch introduces static function filter_display() to replace macro;
> > and refines its parameter with more flexbile way, rather than passing
> > field name, it changes to pass the cache line's statistic value and the
> > sum value.
> []
> > diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> []
> > +static u8 filter_display(u32 val, u32 sum)
> > +{
> > +	double ld_dist;
> > +
> > +	if (sum) {
> > +		ld_dist = ((double)(val) / (sum));
> > +		if (ld_dist < DISPLAY_LINE_LIMIT)
> > +			return HIST_FILTER__C2C;
> > +	} else {
> > +		return HIST_FILTER__C2C;
> > +	}
> > +
> > +	return 0;
> > +}
> 
> style:
> 
> It's generally better to test and return early and unindent the remainder.
> Also, parentheses aren't necessary around now not-macro args.
> 
> {
> 	if (sum == 0 || ((double)val / sum) < DISPLAY_LINE_LIMIT)
> 		return HIST_FILTER__C2C;
> 
> 	return 0;
> }

Will refine for this; thanks for suggestion.

Leo