Re: [PATCH V4 4/7] perf/x86/intel: Support LBR event logging

[Peter Zijlstra]

On Wed, Oct 04, 2023 at 11:40:41AM -0700, kan.liang@xxxxxxxxxxxxxxx wrote:

> +static ssize_t branch_counter_width_show(struct device *cdev,
> +					 struct device_attribute *attr,
> +					 char *buf)
> +{
> +	return snprintf(buf, PAGE_SIZE, "2\n");
> +}

> +#define ARCH_LBR_EVENT_LOG_WIDTH	2

I'm assuming this is the same '2' ? And having it hard-coded in two
locations is awesome..

> +#define ARCH_LBR_EVENT_LOG_MASK		0x3

Should probably be ((1<<2)-1)

As per that other email, the naming is confusing, should this not be:

ARCH_LBR_EVENT_COUNTER_BITS

or, since it's all local to lbr.c something shorter still, like:

LBR_COUNTER_BITS

hmm?