linux-kernel - Re: [PATCH 05/11] perf/amd/ibs: Define macro for ldlat mask

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Message-ID: <9b1806c7-c1ae-44f4-a03a-2a607dcf144e@linux.intel.com>
Date: Mon, 19 Jan 2026 15:38:11 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: Ravi Bangoria <ravi.bangoria@....com>,
 Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
 Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>,
 James Clark <james.clark@...aro.org>, x86@...nel.org,
 linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
 Manali Shukla <manali.shukla@....com>,
 Santosh Shukla <santosh.shukla@....com>,
 Ananth Narayan <ananth.narayan@....com>, Sandipan Das <sandipan.das@....com>
Subject: Re: [PATCH 05/11] perf/amd/ibs: Define macro for ldlat mask


On 1/16/2026 11:34 AM, Ravi Bangoria wrote:
> Load latency filter threshold is encoded in config1[11:0]. Define a mask
> for it instead of hardcoded 0xFFF. Unlike "config" fields whose layout
> maps to PERF_{FETCH|OP}_CTL MSR, layout of "config1" is custom defined
> so a new set of macros are needed for "config1" fields.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
> ---
>  arch/x86/events/amd/ibs.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
> index 27b764eee6c7..02e7bffe1208 100644
> --- a/arch/x86/events/amd/ibs.c
> +++ b/arch/x86/events/amd/ibs.c
> @@ -32,6 +32,9 @@ static u32 ibs_caps;
>  /* attr.config2 */
>  #define IBS_SW_FILTER_MASK	1
>  
> +/* attr.config1 */
> +#define IBS_OP_CONFIG1_LDLAT_MASK		(0xFFFULL <<  0)
> +
>  /*
>   * IBS states:
>   *
> @@ -274,7 +277,7 @@ static bool perf_ibs_ldlat_event(struct perf_ibs *perf_ibs,
>  {
>  	return perf_ibs == &perf_ibs_op &&
>  	       (ibs_caps & IBS_CAPS_OPLDLAT) &&
> -	       (event->attr.config1 & 0xFFF);
> +	       (event->attr.config1 & IBS_OP_CONFIG1_LDLAT_MASK);
>  }
>  
>  static int perf_ibs_init(struct perf_event *event)
> @@ -349,7 +352,7 @@ static int perf_ibs_init(struct perf_event *event)
>  	}
>  
>  	if (perf_ibs_ldlat_event(perf_ibs, event)) {
> -		u64 ldlat = event->attr.config1 & 0xFFF;
> +		u64 ldlat = event->attr.config1 & IBS_OP_CONFIG1_LDLAT_MASK;
>  
>  		if (ldlat < 128 || ldlat > 2048)
>  			return -EINVAL;
> @@ -1302,7 +1305,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
>  		 * within [128, 2048] range.
>  		 */
>  		if (!op_data3.ld_op || !op_data3.dc_miss ||
> -		    op_data3.dc_miss_lat <= (event->attr.config1 & 0xFFF)) {
> +		    op_data3.dc_miss_lat <= (event->attr.config1 & IBS_OP_CONFIG1_LDLAT_MASK)) {
>  			throttle = perf_event_account_interrupt(event);
>  			goto out;
>  		}

Reviewed-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>