Re: [PATCH v3 3/5] perf c2c: Refactor display filter

[Joe Perches]

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;
}