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From: Peter Zijlstra <peterz@infradead.org>
To: kan.liang@linux.intel.com
Cc: mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org,
	mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
	jolsa@kernel.org, namhyung@kernel.org, irogers@google.com,
	adrian.hunter@intel.com, ak@linux.intel.com, eranian@google.com,
	alexey.v.bayduraev@linux.intel.com, tinghao.zhang@intel.com
Subject: Re: [PATCH V4 4/7] perf/x86/intel: Support LBR event logging
Date: Thu, 19 Oct 2023 13:00:56 +0200	[thread overview]
Message-ID: <20231019110056.GH36211@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20231004184044.3062788-4-kan.liang@linux.intel.com>

On Wed, Oct 04, 2023 at 11:40:41AM -0700, kan.liang@linux.intel.com 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?


  parent reply	other threads:[~2023-10-19 11:01 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-04 18:40 [PATCH V4 1/7] perf: Add branch stack counters kan.liang
2023-10-04 18:40 ` [PATCH V4 2/7] perf/x86: Add PERF_X86_EVENT_NEEDS_BRANCH_STACK flag kan.liang
2023-10-04 18:40 ` [PATCH V4 3/7] perf: Add branch_sample_call_stack kan.liang
2023-10-04 18:40 ` [PATCH V4 4/7] perf/x86/intel: Support LBR event logging kan.liang
2023-10-19  9:23   ` Peter Zijlstra
2023-10-19 13:56     ` Liang, Kan
2023-10-19  9:26   ` Peter Zijlstra
2023-10-19 13:58     ` Liang, Kan
2023-10-19 10:52   ` Peter Zijlstra
2023-10-19 14:26     ` Liang, Kan
2023-10-19 18:18       ` Peter Zijlstra
2023-10-19 11:00   ` Peter Zijlstra [this message]
2023-10-19 14:28     ` Liang, Kan
2023-10-19 11:09   ` Peter Zijlstra
2023-10-19 14:31     ` Liang, Kan
2023-10-19 11:12   ` Peter Zijlstra
2023-10-20 12:45     ` Liang, Kan
2023-10-04 18:40 ` [PATCH V4 5/7] tools headers UAPI: Sync include/uapi/linux/perf_event.h header with the kernel kan.liang
2023-10-04 18:40 ` [PATCH V4 6/7] perf header: Support num and width of branch counters kan.liang
2023-10-04 18:40 ` [PATCH V4 7/7] perf tools: Add branch counter knob kan.liang
2023-10-16 17:48 ` [PATCH V4 1/7] perf: Add branch stack counters Liang, Kan

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