linux-kernel - [RFC PATCH V2 5/9] perf/x86/intel: Enable large PEBS for monotonic raw

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Date:   Mon, 13 Feb 2023 11:07:50 -0800
From:   kan.liang@...ux.intel.com
To:     tglx@...utronix.de, jstultz@...gle.com, peterz@...radead.org,
        mingo@...hat.com, linux-kernel@...r.kernel.org
Cc:     sboyd@...nel.org, eranian@...gle.com, namhyung@...nel.org,
        ak@...ux.intel.com, adrian.hunter@...el.com,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: [RFC PATCH V2 5/9] perf/x86/intel: Enable large PEBS for monotonic raw

From: Kan Liang <kan.liang@...ux.intel.com>

The monotonic raw clock is not affected by NTP/PTP correction. The
monotonic raw clock can be calculated from the TSC of each PEBS record
by the same conversion information.

Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
 arch/x86/events/intel/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index d9be5701e60a..eac389e1f44c 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3776,7 +3776,8 @@ static unsigned long intel_pmu_large_pebs_flags(struct perf_event *event)
 {
 	unsigned long flags = x86_pmu.large_pebs_flags;
 
-	if (event->attr.use_clockid)
+	if (event->attr.use_clockid &&
+	    !((x86_pmu.intel_cap.pebs_format >= 3) && perf_event_hw_time(event)))
 		flags &= ~PERF_SAMPLE_TIME;
 	if (!event->attr.exclude_kernel)
 		flags &= ~PERF_SAMPLE_REGS_USER;
-- 
2.35.1