From patchwork Wed Jul 3 22:30:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13722937 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC2011946C7; Wed, 3 Jul 2024 22:30:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720045838; cv=none; b=GSsJVDTQtEhVK6m6f5vta1c/kvb7fG+rgyYv1HKfm/o4R7qyNTCo+a5wePgYMF5djGvihqiZxJpXW+tLcv+QEBv2Ax2KXVm118FIRRMxNNnNdIssBI+QtNs9TjyVdlY6SipaYugl0DhJxQtj+NhW9El6x8I6RLqL5BqTbWIPYaY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720045838; c=relaxed/simple; bh=rbfHsY9w9hApFB/nzPkZ1WXn/UvGNLB9ZwR3TO7Io1Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CCAxEVEhzHEbg+uBBjbsdBBQw0n155MlOOMKyIvIV2+FqNdKah3VluFzq+TtSEJgf0l4vzc8DEeMdER1hvRzHovvmmh+CMmP/Nf3oWBvO9G3iXtYkvKkqnuY41zioaiJYcS2tJiFRhbJ8mVbHcsKSqhYYfWbdm5N+c+gplLXzQA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UFusgQcZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UFusgQcZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A32FC4AF0F; Wed, 3 Jul 2024 22:30:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720045838; bh=rbfHsY9w9hApFB/nzPkZ1WXn/UvGNLB9ZwR3TO7Io1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UFusgQcZ8Y1CKmW8MYconhT6c8VGS81/ysOZ3F0UKzNlUb8W3qwjdAR+Rhm7E1Sph QbLUaU8la6ffE0cs2qiQ85JyYXirLR8iFKMyLaNfeqQruwpCa80zOMX0Fm+SxRzx9y SihFFOlZoLfP+vuODH3nzrxFArr4pV3DpSQJFhLq1L1PQ/EhjgLuCdhfOkaBK6D8Tj ZhuC/egpigeYeHWbJxEG8BXa6GbdeIUpLQfhmlxK6xRA1EbgkXkolgar+E/Mae6V9N Ubb/kq7SzGJcY9GG7vNcWvV2HCxyU3oL127K8uZfJm2Gm4ng024nx5m0Xa73/rkxqQ zz6UGms5OO70g== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers , Kan Liang Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, KP Singh , Song Liu , bpf@vger.kernel.org, Stephane Eranian Subject: [PATCH v3 3/8] perf bpf-filter: Split per-task filter use case Date: Wed, 3 Jul 2024 15:30:30 -0700 Message-ID: <20240703223035.2024586-4-namhyung@kernel.org> X-Mailer: git-send-email 2.45.2.803.g4e1b14247a-goog In-Reply-To: <20240703223035.2024586-1-namhyung@kernel.org> References: <20240703223035.2024586-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 If the target is a list of tasks, it can use a shared hash map for filter expressions. The key of the filter map is an integer index like in an array. A separate pid_hash map is added to get the index for the filter map using the tgid. For system-wide mode including per-cpu or per-user targets are handled by the single entry map like before. Signed-off-by: Namhyung Kim --- tools/perf/util/bpf-filter.c | 186 +++++++++++++++---- tools/perf/util/bpf_skel/sample-filter.h | 1 + tools/perf/util/bpf_skel/sample_filter.bpf.c | 21 +++ 3 files changed, 168 insertions(+), 40 deletions(-) diff --git a/tools/perf/util/bpf-filter.c b/tools/perf/util/bpf-filter.c index 0b2eca56aa10..5ec0e0955ec4 100644 --- a/tools/perf/util/bpf-filter.c +++ b/tools/perf/util/bpf-filter.c @@ -3,10 +3,13 @@ #include #include +#include #include +#include #include "util/debug.h" #include "util/evsel.h" +#include "util/target.h" #include "util/bpf-filter.h" #include @@ -91,38 +94,17 @@ static int check_sample_flags(struct evsel *evsel, struct perf_bpf_filter_expr * return -1; } -int perf_bpf_filter__prepare(struct evsel *evsel, struct target *target __maybe_unused) +static int get_filter_entries(struct evsel *evsel, struct perf_bpf_filter_entry *entry) { - int i, x, y, fd, ret; - struct sample_filter_bpf *skel; - struct bpf_program *prog; - struct bpf_link *link; + int i = 0; struct perf_bpf_filter_expr *expr; - struct perf_bpf_filter_entry *entry; - - entry = calloc(MAX_FILTERS, sizeof(*entry)); - if (entry == NULL) - return -1; - - skel = sample_filter_bpf__open_and_load(); - if (!skel) { - pr_err("Failed to load perf sample-filter BPF skeleton\n"); - ret = -EPERM; - goto err; - } - i = 0; - fd = bpf_map__fd(skel->maps.filters); list_for_each_entry(expr, &evsel->bpf_filters, list) { - if (check_sample_flags(evsel, expr) < 0) { - ret = -EINVAL; - goto err; - } + if (check_sample_flags(evsel, expr) < 0) + return -EINVAL; - if (i == MAX_FILTERS) { - ret = -E2BIG; - goto err; - } + if (i == MAX_FILTERS) + return -E2BIG; entry[i].op = expr->op; entry[i].part = expr->part; @@ -134,10 +116,8 @@ int perf_bpf_filter__prepare(struct evsel *evsel, struct target *target __maybe_ struct perf_bpf_filter_expr *group; list_for_each_entry(group, &expr->groups, list) { - if (i == MAX_FILTERS) { - ret = -E2BIG; - goto err; - } + if (i == MAX_FILTERS) + return -E2BIG; entry[i].op = group->op; entry[i].part = group->part; @@ -146,10 +126,8 @@ int perf_bpf_filter__prepare(struct evsel *evsel, struct target *target __maybe_ i++; } - if (i == MAX_FILTERS) { - ret = -E2BIG; - goto err; - } + if (i == MAX_FILTERS) + return -E2BIG; entry[i].op = PBF_OP_GROUP_END; i++; @@ -161,15 +139,143 @@ int perf_bpf_filter__prepare(struct evsel *evsel, struct target *target __maybe_ entry[i].op = PBF_OP_DONE; i++; } + return 0; +} + +static int convert_to_tgid(int tid) +{ + char path[128]; + char *buf, *p, *q; + int tgid; + size_t len; + + scnprintf(path, sizeof(path), "%d/status", tid); + if (procfs__read_str(path, &buf, &len) < 0) + return -1; - /* The filters map has only one entry for now */ - i = 0; - if (bpf_map_update_elem(fd, &i, entry, BPF_ANY) < 0) { - ret = -errno; - pr_err("Failed to update the filter map\n"); + p = strstr(buf, "Tgid:"); + if (p == NULL) { + free(buf); + return -1; + } + + tgid = strtol(p + 6, &q, 0); + free(buf); + if (*q != '\n') + return -1; + + return tgid; +} + +static int update_pid_hash(struct sample_filter_bpf *skel, struct evsel *evsel, + struct perf_bpf_filter_entry *entry) +{ + int filter_idx; + int nr, last; + int fd = bpf_map__fd(skel->maps.filters); + struct perf_thread_map *threads; + + /* Find the first available entry in the filters map */ + for (filter_idx = 0; filter_idx < MAX_FILTERS; filter_idx++) { + if (bpf_map_update_elem(fd, &filter_idx, entry, BPF_NOEXIST) == 0) + break; + } + + if (filter_idx == MAX_FILTERS) { + pr_err("Too many users for the filter map\n"); + return -EBUSY; + } + + threads = perf_evsel__threads(&evsel->core); + if (threads == NULL) { + pr_err("Cannot get the thread list of the event\n"); + return -EINVAL; + } + + /* save the index to a hash map */ + fd = bpf_map__fd(skel->maps.pid_hash); + + last = -1; + nr = perf_thread_map__nr(threads); + for (int i = 0; i < nr; i++) { + int pid = perf_thread_map__pid(threads, i); + int tgid; + + /* it actually needs tgid, let's get tgid from /proc. */ + tgid = convert_to_tgid(pid); + if (tgid < 0) { + /* the thread may be dead, ignore. */ + continue; + } + + if (tgid == last) + continue; + last = tgid; + + if (bpf_map_update_elem(fd, &tgid, &filter_idx, BPF_ANY) < 0) { + pr_err("Failed to update the pid hash\n"); + return -errno; + } + pr_debug("pid hash: %d -> %d\n", tgid, filter_idx); + } + return 0; +} + +int perf_bpf_filter__prepare(struct evsel *evsel, struct target *target) +{ + int i, x, y, fd, ret; + struct sample_filter_bpf *skel = NULL; + struct bpf_program *prog; + struct bpf_link *link; + struct perf_bpf_filter_entry *entry; + bool needs_pid_hash = !target__has_cpu(target) && !target->uid_str; + + entry = calloc(MAX_FILTERS, sizeof(*entry)); + if (entry == NULL) + return -1; + + ret = get_filter_entries(evsel, entry); + if (ret < 0) { + pr_err("Failed to process filter entries\n"); + goto err; + } + + skel = sample_filter_bpf__open(); + if (!skel) { + pr_err("Failed to open perf sample-filter BPF skeleton\n"); + ret = -EPERM; goto err; } + if (needs_pid_hash) { + bpf_map__set_max_entries(skel->maps.filters, MAX_FILTERS); + bpf_map__set_max_entries(skel->maps.pid_hash, MAX_PIDS); + skel->rodata->use_pid_hash = 1; + } + + if (sample_filter_bpf__load(skel) < 0) { + pr_err("Failed to load perf sample-filter BPF skeleton\n"); + ret = -EPERM; + goto err; + } + + if (needs_pid_hash) { + /* The filters map is shared among other processes */ + ret = update_pid_hash(skel, evsel, entry); + if (ret < 0) + goto err; + } else { + i = 0; + fd = bpf_map__fd(skel->maps.filters); + + /* The filters map has only one entry in this case */ + if (bpf_map_update_elem(fd, &i, entry, BPF_ANY) < 0) { + ret = -errno; + pr_err("Failed to update the filter map\n"); + goto err; + } + } + prog = skel->progs.perf_sample_filter; for (x = 0; x < xyarray__max_x(evsel->core.fd); x++) { for (y = 0; y < xyarray__max_y(evsel->core.fd); y++) { diff --git a/tools/perf/util/bpf_skel/sample-filter.h b/tools/perf/util/bpf_skel/sample-filter.h index bb6a1b91f1df..e666bfd5fbdd 100644 --- a/tools/perf/util/bpf_skel/sample-filter.h +++ b/tools/perf/util/bpf_skel/sample-filter.h @@ -2,6 +2,7 @@ #define PERF_UTIL_BPF_SKEL_SAMPLE_FILTER_H #define MAX_FILTERS 64 +#define MAX_PIDS (16 * 1024) /* supported filter operations */ enum perf_bpf_filter_op { diff --git a/tools/perf/util/bpf_skel/sample_filter.bpf.c b/tools/perf/util/bpf_skel/sample_filter.bpf.c index 0d56e52b922c..c5273f06fa45 100644 --- a/tools/perf/util/bpf_skel/sample_filter.bpf.c +++ b/tools/perf/util/bpf_skel/sample_filter.bpf.c @@ -15,7 +15,16 @@ struct filters { __uint(max_entries, 1); } filters SEC(".maps"); +/* tgid to filter index */ +struct pid_hash { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, int); + __type(value, int); + __uint(max_entries, 1); +} pid_hash SEC(".maps"); + int dropped; +volatile const int use_pid_hash; void *bpf_cast_to_kern_ctx(void *) __ksym; @@ -184,6 +193,18 @@ int perf_sample_filter(void *ctx) kctx = bpf_cast_to_kern_ctx(ctx); k = 0; + + if (use_pid_hash) { + int tgid = bpf_get_current_pid_tgid() >> 32; + int *idx; + + idx = bpf_map_lookup_elem(&pid_hash, &tgid); + if (idx) + k = *idx; + else + goto drop; + } + entry = bpf_map_lookup_elem(&filters, &k); if (entry == NULL) goto drop;