linux-kernel - [PATCH 01/11] perf/amd/ibs: Throttle interrupts with filtered ldlat samples

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Message-ID: <20260116033450.965-2-ravi.bangoria@amd.com>
Date: Fri, 16 Jan 2026 03:34:40 +0000
From: Ravi Bangoria <ravi.bangoria@....com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>
CC: Ravi Bangoria <ravi.bangoria@....com>, Arnaldo Carvalho de Melo
	<acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Ian Rogers
	<irogers@...gle.com>, Dapeng Mi <dapeng1.mi@...ux.intel.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: [PATCH 01/11] perf/amd/ibs: Throttle interrupts with filtered ldlat samples

IBS NMI handler has a software filter (on top of hardware filter) to
discard samples with load latency value lesser than user requested
threshold. However, since software filter still involves NMI, check
for NMI overhead and throttle the sample rate if needed.

Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
---
 arch/x86/events/amd/ibs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index aca89f23d2e0..96bb0974057f 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -1293,8 +1293,10 @@ 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 & 0xFFF)) {
+			throttle = perf_event_account_interrupt(event);
 			goto out;
+		}
 	}
 
 	/*
-- 
2.43.0