From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 446331ACEDA; Tue, 26 Aug 2025 13:43:25 +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=1756215807; cv=none; b=YLdvFT2dTzEKsfnMgeUqN+Gw78rZpQFml+C33OKcqNYn4zr5p7uQg/kwAJi6bklqbapAq0i/vwldKuW2TdEj47eBmwC/fiy6d4QXUCCM6vZlQ/Crxb411mBrMM9gaVoPCYQdEhm343EDXAcNVLtUphJt7Ps5+zFmHOUBJsokuYU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756215807; c=relaxed/simple; bh=NSFdsUFlpKhN8H0ekHru05yw4WSdjN+zOrEkvz1mKVQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WVkLxr91RFrGSaBzdALgbmE2/n2dSCsNxWPKBs7kEIbkeu14ey2Qqo88OoKH2EtRNCVflCjcjnWmHvr3Ls1isB8o5ya118iNhPsP4K9PgnkB6YZ/Nz8ubON70M7kn4nu4Kbxps9EmP0HOMvog8npPGiiRIfr8SH86aWkrVZY3nI= 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 5E7311A25; Tue, 26 Aug 2025 06:43:16 -0700 (PDT) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8B8A73F63F; Tue, 26 Aug 2025 06:43:18 -0700 (PDT) Date: Tue, 26 Aug 2025 14:43:16 +0100 From: Mark Rutland To: Robin Murphy Cc: peterz@infradead.org, mingo@redhat.com, will@kernel.org, acme@kernel.org, namhyung@kernel.org, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, imx@lists.linux.dev, linux-csky@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-pm@vger.kernel.org, linux-rockchip@lists.infradead.org, dmaengine@vger.kernel.org, linux-fpga@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, coresight@lists.linaro.org, iommu@lists.linux.dev, linux-amlogic@lists.infradead.org, linux-cxl@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH 18/19] perf: Introduce positive capability for raw events Message-ID: References: <542787fd188ea15ef41c53d557989c962ed44771.1755096883.git.robin.murphy@arm.com> Precedence: bulk X-Mailing-List: linux-fpga@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <542787fd188ea15ef41c53d557989c962ed44771.1755096883.git.robin.murphy@arm.com> On Wed, Aug 13, 2025 at 06:01:10PM +0100, Robin Murphy wrote: > Only a handful of CPU PMUs accept PERF_TYPE_{RAW,HARDWARE,HW_CACHE} > events without registering themselves as PERF_TYPE_RAW in the first > place. Add an explicit opt-in for these special cases, so that we can > make life easier for every other driver (and probably also speed up the > slow-path search) by having perf_try_init_event() do the basic type > checking to cover the majority of cases. > > Signed-off-by: Robin Murphy To bikeshed a little here, I'm not keen on the PERF_PMU_CAP_RAW_EVENTS name, because it's not clear what "RAW" really means, and people will definitely read that to mean something else. Could we go with something like PERF_PMU_CAP_COMMON_CPU_EVENTS, to make it clear that this is about opting into CPU-PMU specific event types (of which PERF_TYPE_RAW is one of)? Likewise, s/is_raw_pmu()/pmu_supports_common_cpu_events()/. > --- > > A further possibility is to automatically add the cap to PERF_TYPE_RAW > PMUs in perf_pmu_register() to have a single point-of-use condition; I'm > undecided... I reckon we don't need to automagically do that, but I reckon that is_raw_pmu()/pmu_supports_common_cpu_events() should only check the cap, and we don't read anything special into any of PERF_TYPE_{RAW,HARDWARE,HW_CACHE}. > --- > arch/s390/kernel/perf_cpum_cf.c | 1 + > arch/s390/kernel/perf_pai_crypto.c | 2 +- > arch/s390/kernel/perf_pai_ext.c | 2 +- > arch/x86/events/core.c | 2 +- > drivers/perf/arm_pmu.c | 1 + > include/linux/perf_event.h | 1 + > kernel/events/core.c | 15 +++++++++++++++ > 7 files changed, 21 insertions(+), 3 deletions(-) > > diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c > index 1a94e0944bc5..782ab755ddd4 100644 > --- a/arch/s390/kernel/perf_cpum_cf.c > +++ b/arch/s390/kernel/perf_cpum_cf.c > @@ -1054,6 +1054,7 @@ static void cpumf_pmu_del(struct perf_event *event, int flags) > /* Performance monitoring unit for s390x */ > static struct pmu cpumf_pmu = { > .task_ctx_nr = perf_sw_context, > + .capabilities = PERF_PMU_CAP_RAW_EVENTS, > .pmu_enable = cpumf_pmu_enable, > .pmu_disable = cpumf_pmu_disable, > .event_init = cpumf_pmu_event_init, Tangential, but use of perf_sw_context here looks bogus. > diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c > index a64b6b056a21..b5b6d8b5d943 100644 > --- a/arch/s390/kernel/perf_pai_crypto.c > +++ b/arch/s390/kernel/perf_pai_crypto.c > @@ -569,7 +569,7 @@ static const struct attribute_group *paicrypt_attr_groups[] = { > /* Performance monitoring unit for mapped counters */ > static struct pmu paicrypt = { > .task_ctx_nr = perf_hw_context, > - .capabilities = PERF_PMU_CAP_SAMPLING, > + .capabilities = PERF_PMU_CAP_SAMPLING | PERF_PMU_CAP_RAW_EVENTS, > .event_init = paicrypt_event_init, > .add = paicrypt_add, > .del = paicrypt_del, > diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c > index 1261f80c6d52..bcd28c38da70 100644 > --- a/arch/s390/kernel/perf_pai_ext.c > +++ b/arch/s390/kernel/perf_pai_ext.c > @@ -595,7 +595,7 @@ static const struct attribute_group *paiext_attr_groups[] = { > /* Performance monitoring unit for mapped counters */ > static struct pmu paiext = { > .task_ctx_nr = perf_hw_context, > - .capabilities = PERF_PMU_CAP_SAMPLING, > + .capabilities = PERF_PMU_CAP_SAMPLING | PERF_PMU_CAP_RAW_EVENTS, > .event_init = paiext_event_init, > .add = paiext_add, > .del = paiext_del, > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c > index 789dfca2fa67..764728bb80ae 100644 > --- a/arch/x86/events/core.c > +++ b/arch/x86/events/core.c > @@ -2697,7 +2697,7 @@ static bool x86_pmu_filter(struct pmu *pmu, int cpu) > } > > static struct pmu pmu = { > - .capabilities = PERF_PMU_CAP_SAMPLING, > + .capabilities = PERF_PMU_CAP_SAMPLING | PERF_PMU_CAP_RAW_EVENTS, > > .pmu_enable = x86_pmu_enable, > .pmu_disable = x86_pmu_disable, > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index 72d8f38d0aa5..bc772a3bf411 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -877,6 +877,7 @@ struct arm_pmu *armpmu_alloc(void) > * specific PMU. > */ > .capabilities = PERF_PMU_CAP_SAMPLING | > + PERF_PMU_CAP_RAW_EVENTS | > PERF_PMU_CAP_EXTENDED_REGS | > PERF_PMU_CAP_EXTENDED_HW_TYPE, > }; > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 183b7c48b329..c6ad036c0037 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -305,6 +305,7 @@ struct perf_event_pmu_context; > #define PERF_PMU_CAP_EXTENDED_HW_TYPE 0x0100 > #define PERF_PMU_CAP_AUX_PAUSE 0x0200 > #define PERF_PMU_CAP_AUX_PREFER_LARGE 0x0400 > +#define PERF_PMU_CAP_RAW_EVENTS 0x0800 > > /** > * pmu::scope > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 71b2a6730705..2ecee76d2ae2 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -12556,11 +12556,26 @@ static inline bool has_extended_regs(struct perf_event *event) > (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); > } > > +static bool is_raw_pmu(const struct pmu *pmu) > +{ > + return pmu->type == PERF_TYPE_RAW || > + pmu->capabilities & PERF_PMU_CAP_RAW_EVENTS; > +} As above, I reckon we should make this: static bool pmu_supports_common_cpu_events(const struct pmu *pmu) { return pmu->capabilities & PERF_PMU_CAP_RAW_EVENTS; } Other than the above, this looks good to me. Mark. > + > static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) > { > struct perf_event_context *ctx = NULL; > int ret; > > + /* > + * Before touching anything, we can safely skip: > + * - any event for a specific PMU which is not this one > + * - any common event if this PMU doesn't support them > + */ > + if (event->attr.type != pmu->type && > + (event->attr.type >= PERF_TYPE_MAX || is_raw_pmu(pmu))) > + return -ENOENT; > + > if (!try_module_get(pmu->module)) > return -ENODEV; > > -- > 2.39.2.101.g768bb238c484.dirty >