From nobody Wed Dec 24 23:36:57 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A27E55D8FE; Tue, 23 Jan 2024 11:34:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706009684; cv=none; b=pJZLN9ahEWkzuim2h72HC/PcCdn1bizF7i9KtEqL8rHk78oA7IzMUHqnZWsXeUvLXF8pT612NUlYAss9K6fanQr82syg+0bd6iso4dBGzqtA1Zguc7O8x3asOdRfzmAFJBWHNCvcYeC5Uw8t7qWcooj+t8BjzfROA9ZmdSd5UGc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706009684; c=relaxed/simple; bh=Ev/78lNrKeEn0GKrbVaNQkMKhQsuAjKk6QQf3ZBpTYE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KPIrecwmKVn+60hgWVZ4zPvyEIyVTLpqi8FTsmdIDcGhXwQ8nlcDQdvrNHHt6MS8qdLfdBQpRWGr17iu2DZvGO4yIZVgcaGBELCkKoAUa46nGzjRRAiNCNpZxcT4cCGsyxiX3ROv+qbLLPhPUDbFNOc0sVpKvRIBPptcwWHMkyk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 40622106F; Tue, 23 Jan 2024 03:35:27 -0800 (PST) Received: from e126817.. (e126817.cambridge.arm.com [10.2.3.5]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 130203F762; Tue, 23 Jan 2024 03:34:39 -0800 (PST) From: Ben Gainey To: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.com, will@kernel.org, Ben Gainey Subject: [RFC PATCH 2/2] arm_pmuv3: Add config bits for sample period strobing Date: Tue, 23 Jan 2024 11:34:20 +0000 Message-ID: <20240123113420.1928154-3-ben.gainey@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240123113420.1928154-1-ben.gainey@arm.com> References: <20240123113420.1928154-1-ben.gainey@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To expose the ability to alternate between sample periods to tools. The field `strobe_period` is defined for config2 to hold the alternate sample period. A non-zero value will enable strobing. Signed-off-by: Ben Gainey --- drivers/perf/arm_pmuv3.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 23fa6c5da82c4..66b0219111bb8 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -318,6 +318,9 @@ static const struct attribute_group armv8_pmuv3_events_= attr_group =3D { #define ATTR_CFG_FLD_threshold_CFG config1 /* PMEVTYPER.TH */ #define ATTR_CFG_FLD_threshold_LO 5 #define ATTR_CFG_FLD_threshold_HI 16 +#define ATTR_CFG_FLD_strobe_period_CFG config2 +#define ATTR_CFG_FLD_strobe_period_LO 0 +#define ATTR_CFG_FLD_strobe_period_HI 31 =20 GEN_PMU_FORMAT_ATTR(event); GEN_PMU_FORMAT_ATTR(long); @@ -325,6 +328,7 @@ GEN_PMU_FORMAT_ATTR(rdpmc); GEN_PMU_FORMAT_ATTR(threshold_count); GEN_PMU_FORMAT_ATTR(threshold_compare); GEN_PMU_FORMAT_ATTR(threshold); +GEN_PMU_FORMAT_ATTR(strobe_period); =20 static int sysctl_perf_user_access __read_mostly; =20 @@ -352,6 +356,16 @@ static u8 armv8pmu_event_threshold_control(struct perf= _event_attr *attr) return (th_compare << 1) | th_count; } =20 +static inline u32 armv8pmu_event_strobe_period(struct perf_event *event) +{ + return ATTR_CFG_GET_FLD(&event->attr, strobe_period); +} + +static inline bool armv8pmu_event_want_strobe(struct perf_event *event) +{ + return armv8pmu_event_strobe_period(event) !=3D 0; +} + static struct attribute *armv8_pmuv3_format_attrs[] =3D { &format_attr_event.attr, &format_attr_long.attr, @@ -359,6 +373,7 @@ static struct attribute *armv8_pmuv3_format_attrs[] =3D= { &format_attr_threshold.attr, &format_attr_threshold_compare.attr, &format_attr_threshold_count.attr, + &format_attr_strobe_period.attr, NULL, }; =20 @@ -1125,6 +1140,16 @@ static int __armv8_pmuv3_map_event(struct perf_event= *event, if (armv8pmu_event_is_64bit(event)) event->hw.flags |=3D ARMPMU_EVT_64BIT; =20 + /* + * Support alternating between two sample periods + */ + if (armv8pmu_event_want_strobe(event)) { + u32 strobe_period =3D armv8pmu_event_strobe_period(event); + armpmu_set_strobe_period(&(event->hw), strobe_period); + } else { + armpmu_set_strobe_period(&(event->hw), 0); + } + /* * User events must be allocated into a single counter, and so * must not be chained. --=20 2.43.0