linux-kernel - [PATCH AUTOSEL 6.0 06/11] perf: RISC-V: throttle perf events

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Date:   Fri, 14 Oct 2022 09:51:32 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Sergey Matyukevich <sergey.matyukevich@...tacore.com>,
        Atish Patra <atishp@...osinc.com>,
        Palmer Dabbelt <palmer@...osinc.com>,
        Sasha Levin <sashal@...nel.org>, atishp@...shpatra.org,
        will@...nel.org, mark.rutland@....com, paul.walmsley@...ive.com,
        palmer@...belt.com, aou@...s.berkeley.edu,
        linux-riscv@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH AUTOSEL 6.0 06/11] perf: RISC-V: throttle perf events

From: Sergey Matyukevich <sergey.matyukevich@...tacore.com>

[ Upstream commit 096b52fd2bb4996fd68d22b3b7ad21a1296db9d3 ]

Call perf_sample_event_took() to report time spent in overflow
interrupts. Perf core uses these measurements to throttle
perf events properly.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich@...tacore.com>
Reviewed-by: Atish Patra <atishp@...osinc.com>
Link: https://lore.kernel.org/r/20220830155306.301714-4-geomatsi@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@...osinc.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/perf/riscv_pmu_sbi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 8de4ca2fef21..88e326c5f63b 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -18,6 +18,7 @@
 #include <linux/of_irq.h>
 #include <linux/of.h>
 #include <linux/cpu_pm.h>
+#include <linux/sched/clock.h>
 
 #include <asm/sbi.h>
 #include <asm/hwcap.h>
@@ -567,6 +568,7 @@ static irqreturn_t pmu_sbi_ovf_handler(int irq, void *dev)
 	unsigned long overflow;
 	unsigned long overflowed_ctrs = 0;
 	struct cpu_hw_events *cpu_hw_evt = dev;
+	u64 start_clock = sched_clock();
 
 	if (WARN_ON_ONCE(!cpu_hw_evt))
 		return IRQ_NONE;
@@ -635,7 +637,9 @@ static irqreturn_t pmu_sbi_ovf_handler(int irq, void *dev)
 			perf_event_overflow(event, &data, regs);
 		}
 	}
+
 	pmu_sbi_start_overflow_mask(pmu, overflowed_ctrs);
+	perf_sample_event_took(sched_clock() - start_clock);
 
 	return IRQ_HANDLED;
 }
-- 
2.35.1