From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E7ADC433E2 for ; Fri, 28 Aug 2020 20:56:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2E2F2075B for ; Fri, 28 Aug 2020 20:56:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598648207; bh=CSg41EklHo5ux/7z0GRA1v8ycbTj6fp/T+y905ohH1U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gXCTDn4vfQTuptT9KQNodgOa74HywQ70EmE2mI9HV5XDzG1aEz0WDiwiO1BE/mB1r og6iQikPL1oyeBJVUmTnEsPndEM8mFgroRTMAvKuedfRzvIqxwZyWT/qMFscLQVc/k Fhu3zHosMFUHPTKXVDJprWc/fncvYD2lZcaB/3S4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727050AbgH1U4p (ORCPT ); Fri, 28 Aug 2020 16:56:45 -0400 Received: from mail-il1-f196.google.com ([209.85.166.196]:33764 "EHLO mail-il1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726851AbgH1U4e (ORCPT ); Fri, 28 Aug 2020 16:56:34 -0400 Received: by mail-il1-f196.google.com with SMTP id o16so1834687ilq.0 for ; Fri, 28 Aug 2020 13:56:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=/ZC0zq9fKiDAM/vCSzINCe0QxnZP4kkJJtNDJAgLt1A=; b=CSh4+dYzfz/gCRy7Rq9zAA+d5TDeNjcNWMUQibLb6mn+bk4jqTrxnwYB2athMmu76j YqwIU5v9GiamPRHpITmWrwp2rJTgdXyuTEMiJ/xBwKSWodxtKqLc0N6+AmbXMO4J//DU N7yN6FKubhh3ZPio7bpnu+eCZIbAttFu5KduqPOIK8aYCASuFJSe0u0e+KUPZYG5Cfcs UF4iAx6ZVGL/xKWxPgSyeqn1PBiz+Z6GI49Vp6OL+d6dEWIK76TT8XYmoENRXwNWN0vc 1WcZwSMveX1p9uUPQc6zVgHkAbhhIqiSilso1aYeQ4Ob6zS2gTirLBicwRBbBrLCg58y 59OA== X-Gm-Message-State: AOAM531kwznSviPEye+kEsRjzZXg4KZ7IF8ZosKeGyhclt/iYY4QVNNA lGICnijWGy7aHQceElxGBg== X-Google-Smtp-Source: ABdhPJx39whLoKNoo1l1H7JWTqu2UYWtaGk1YvXZbs+BC3DBxKjfcBH96XKe2kbLlGuHqiWHTxHX4A== X-Received: by 2002:a05:6e02:104e:: with SMTP id p14mr647111ilj.76.1598648189612; Fri, 28 Aug 2020 13:56:29 -0700 (PDT) Received: from xps15.herring.priv ([64.188.179.249]) by smtp.googlemail.com with ESMTPSA id l203sm147089ioa.31.2020.08.28.13.56.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Aug 2020 13:56:29 -0700 (PDT) From: Rob Herring To: Will Deacon , Catalin Marinas , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Jiri Olsa Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alexander Shishkin , Namhyung Kim , Raphael Gault , Mark Rutland , Jonathan Cameron , Ian Rogers , honnappa.nagarahalli@arm.com Subject: [PATCH v2 5/9] libperf: Add support for user space counter access Date: Fri, 28 Aug 2020 14:56:10 -0600 Message-Id: <20200828205614.3391252-6-robh@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200828205614.3391252-1-robh@kernel.org> References: <20200828205614.3391252-1-robh@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org x86 and arm64 can both support direct access of event counters in userspace. The access sequence is less than trivial and currently exists in perf test code (tools/perf/arch/x86/tests/rdpmc.c) with copies in projects such as PAPI and libpfm4. In order to support usersapce access, an event must be mmapped. While there's already mmap support for evlist, the usecase is a bit different than the self monitoring with userspace access. So let's add a new perf_evsel__mmap() function to mmap an evsel. This allows implementing userspace access as a fastpath for perf_evsel__read(). The mmapped address is returned by perf_evsel__mmap() primarily for users/tests to check if userspace access is enabled. Signed-off-by: Rob Herring --- tools/lib/perf/Documentation/libperf.txt | 1 + tools/lib/perf/evsel.c | 33 +++++++++ tools/lib/perf/include/internal/evsel.h | 2 + tools/lib/perf/include/internal/mmap.h | 3 + tools/lib/perf/include/perf/evsel.h | 1 + tools/lib/perf/libperf.map | 1 + tools/lib/perf/mmap.c | 90 ++++++++++++++++++++++++ tools/lib/perf/tests/test-evsel.c | 64 +++++++++++++++++ 8 files changed, 195 insertions(+) diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt index 0c74c30ed23a..ca7478acc97c 100644 --- a/tools/lib/perf/Documentation/libperf.txt +++ b/tools/lib/perf/Documentation/libperf.txt @@ -136,6 +136,7 @@ SYNOPSIS struct perf_thread_map *threads); void perf_evsel__close(struct perf_evsel *evsel); void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu); + void *perf_evsel__mmap(struct perf_evsel *evsel); int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, struct perf_counts_values *count); int perf_evsel__enable(struct perf_evsel *evsel); diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c index 4dc06289f4c7..b0c94ef4d9b6 100644 --- a/tools/lib/perf/evsel.c +++ b/tools/lib/perf/evsel.c @@ -11,10 +11,12 @@ #include #include #include +#include #include #include #include #include +#include void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr) { @@ -156,6 +158,34 @@ void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu) perf_evsel__close_fd_cpu(evsel, cpu); } +void *perf_evsel__mmap(struct perf_evsel *evsel) +{ + int ret; + struct perf_mmap *map; + struct perf_mmap_param mp = { + .mask = -1, + .prot = PROT_READ | PROT_WRITE, + }; + + if (FD(evsel, 0, 0) < 0) + return NULL; + + map = zalloc(sizeof(*map)); + if (!map) + return NULL; + + perf_mmap__init(map, NULL, false, NULL); + + ret = perf_mmap__mmap(map, &mp, FD(evsel, 0, 0), 0); + if (ret) { + free(map); + return NULL; + } + + evsel->mmap = map; + return map->base; +} + int perf_evsel__read_size(struct perf_evsel *evsel) { u64 read_format = evsel->attr.read_format; @@ -191,6 +221,9 @@ int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, if (FD(evsel, cpu, thread) < 0) return -EINVAL; + if (evsel->mmap && !perf_mmap__read_self(evsel->mmap, count)) + return 0; + if (readn(FD(evsel, cpu, thread), count->values, size) <= 0) return -errno; diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h index 1ffd083b235e..a7985dbb68ff 100644 --- a/tools/lib/perf/include/internal/evsel.h +++ b/tools/lib/perf/include/internal/evsel.h @@ -9,6 +9,7 @@ struct perf_cpu_map; struct perf_thread_map; +struct perf_mmap; struct xyarray; /* @@ -40,6 +41,7 @@ struct perf_evsel { struct perf_cpu_map *cpus; struct perf_cpu_map *own_cpus; struct perf_thread_map *threads; + struct perf_mmap *mmap; struct xyarray *fd; struct xyarray *sample_id; u64 *id; diff --git a/tools/lib/perf/include/internal/mmap.h b/tools/lib/perf/include/internal/mmap.h index be7556e0a2b2..5e3422f40ed5 100644 --- a/tools/lib/perf/include/internal/mmap.h +++ b/tools/lib/perf/include/internal/mmap.h @@ -11,6 +11,7 @@ #define PERF_SAMPLE_MAX_SIZE (1 << 16) struct perf_mmap; +struct perf_counts_values; typedef void (*libperf_unmap_cb_t)(struct perf_mmap *map); @@ -52,4 +53,6 @@ void perf_mmap__put(struct perf_mmap *map); u64 perf_mmap__read_head(struct perf_mmap *map); +int perf_mmap__read_self(struct perf_mmap *map, struct perf_counts_values *count); + #endif /* __LIBPERF_INTERNAL_MMAP_H */ diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h index c82ec39a4ad0..6d0da962870c 100644 --- a/tools/lib/perf/include/perf/evsel.h +++ b/tools/lib/perf/include/perf/evsel.h @@ -27,6 +27,7 @@ LIBPERF_API int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map * struct perf_thread_map *threads); LIBPERF_API void perf_evsel__close(struct perf_evsel *evsel); LIBPERF_API void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu); +LIBPERF_API void *perf_evsel__mmap(struct perf_evsel *evsel); LIBPERF_API int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, struct perf_counts_values *count); LIBPERF_API int perf_evsel__enable(struct perf_evsel *evsel); diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map index 7be1af8a546c..733a0647be8b 100644 --- a/tools/lib/perf/libperf.map +++ b/tools/lib/perf/libperf.map @@ -23,6 +23,7 @@ LIBPERF_0.0.1 { perf_evsel__disable; perf_evsel__open; perf_evsel__close; + perf_evsel__mmap; perf_evsel__read; perf_evsel__cpus; perf_evsel__threads; diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c index 79d5ed6c38cc..cb07969cfdbf 100644 --- a/tools/lib/perf/mmap.c +++ b/tools/lib/perf/mmap.c @@ -8,9 +8,11 @@ #include #include #include +#include #include #include #include +#include #include "internal.h" void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev, @@ -273,3 +275,91 @@ union perf_event *perf_mmap__read_event(struct perf_mmap *map) return event; } + +#if defined(__i386__) || defined(__x86_64__) +static u64 read_perf_counter(unsigned int counter) +{ + unsigned int low, high; + + asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter)); + + return low | ((u64)high) << 32; +} + +static u64 read_timestamp(void) +{ + unsigned int low, high; + + asm volatile("rdtsc" : "=a" (low), "=d" (high)); + + return low | ((u64)high) << 32; +} +#else +static u64 read_perf_counter(unsigned int counter) { return 0; } +static u64 read_timestamp(void) { return 0; } +#endif + +int perf_mmap__read_self(struct perf_mmap *map, struct perf_counts_values *count) +{ + struct perf_event_mmap_page *pc = map->base; + u32 seq, idx, time_mult = 0, time_shift = 0; + u64 cnt, cyc = 0, time_offset = 0, time_cycles = 0, time_mask = ~0ULL; + + BUG_ON(!pc); + + if (!pc->cap_user_rdpmc) + return -1; + + do { + seq = READ_ONCE(pc->lock); + barrier(); + + count->ena = READ_ONCE(pc->time_enabled); + count->run = READ_ONCE(pc->time_running); + + if (pc->cap_user_time && count->ena != count->run) { + cyc = read_timestamp(); + time_mult = READ_ONCE(pc->time_mult); + time_shift = READ_ONCE(pc->time_shift); + time_offset = READ_ONCE(pc->time_offset); + + if (pc->cap_user_time_short) { + time_cycles = READ_ONCE(pc->time_cycles); + time_mask = READ_ONCE(pc->time_mask); + } + } + + idx = READ_ONCE(pc->index); + cnt = READ_ONCE(pc->offset); + if (pc->cap_user_rdpmc && idx) { + u64 evcnt = read_perf_counter(idx - 1); + u16 width = READ_ONCE(pc->pmc_width); + + evcnt <<= 64 - width; + evcnt >>= 64 - width; + cnt += evcnt; + } else + return -1; + + barrier(); + } while (READ_ONCE(pc->lock) != seq); + + if (count->ena != count->run) { + u64 delta; + + /* Adjust for cap_usr_time_short, a nop if not */ + cyc = time_cycles + ((cyc - time_cycles) & time_mask); + + delta = time_offset + mul_u64_u32_shr(cyc, time_mult, time_shift); + + count->ena += delta; + if (idx) + count->run += delta; + + cnt = mul_u64_u64_div64(cnt, count->ena, count->run); + } + + count->val = cnt; + + return 0; +} diff --git a/tools/lib/perf/tests/test-evsel.c b/tools/lib/perf/tests/test-evsel.c index 135722ac965b..fd637d23216b 100644 --- a/tools/lib/perf/tests/test-evsel.c +++ b/tools/lib/perf/tests/test-evsel.c @@ -120,6 +120,68 @@ static int test_stat_thread_enable(void) return 0; } +static int test_stat_user_read(int event) +{ + struct perf_counts_values counts = { .val = 0 }; + struct perf_thread_map *threads; + struct perf_evsel *evsel; + struct perf_event_mmap_page *pc; + struct perf_event_attr attr = { + .type = PERF_TYPE_HARDWARE, + .config = event, + }; + int err, i; + + threads = perf_thread_map__new_dummy(); + __T("failed to create threads", threads); + + perf_thread_map__set_pid(threads, 0, 0); + + evsel = perf_evsel__new(&attr); + __T("failed to create evsel", evsel); + + err = perf_evsel__open(evsel, NULL, threads); + __T("failed to open evsel", err == 0); + + pc = perf_evsel__mmap(evsel); + __T("failed to mmap evsel", pc); + +#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) + __T("userspace counter access not supported", pc->cap_user_rdpmc); + __T("userspace counter access not enabled", pc->index); + __T("userspace counter width not set", pc->pmc_width >= 32); +#endif + + perf_evsel__read(evsel, 0, 0, &counts); + __T("failed to read value for evsel", counts.val != 0); + + fputs("\n", stderr); + for (i = 0; i < 5; i++) { + volatile int count = 0x10000 << i; + __u64 start, end, last = 0; + + fprintf(stderr, "\tloop = %u, ", count); + + perf_evsel__read(evsel, 0, 0, &counts); + start = counts.val; + + while (count--) ; + + perf_evsel__read(evsel, 0, 0, &counts); + end = counts.val; + + __T("invalid counter data", (end - start) > last); + last = end - start; + fprintf(stderr, "count = %llu\n", end - start); + } + + perf_evsel__close(evsel); + perf_evsel__delete(evsel); + + perf_thread_map__put(threads); + return 0; +} + int main(int argc, char **argv) { __T_START; @@ -129,6 +191,8 @@ int main(int argc, char **argv) test_stat_cpu(); test_stat_thread(); test_stat_thread_enable(); + test_stat_user_read(PERF_COUNT_HW_INSTRUCTIONS); + test_stat_user_read(PERF_COUNT_HW_CPU_CYCLES); __T_END; return 0; -- 2.25.1