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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 5892CC4646B for ; Wed, 26 Jun 2019 06:12:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3433C2085A for ; Wed, 26 Jun 2019 06:12:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="jjj06Udl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726820AbfFZGMx (ORCPT ); Wed, 26 Jun 2019 02:12:53 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:15584 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725930AbfFZGMw (ORCPT ); Wed, 26 Jun 2019 02:12:52 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.27/8.16.0.27) with SMTP id x5Q686hj025551 for ; Tue, 25 Jun 2019 23:12:51 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=0BpgaC9tmhPMCaDRLWkpfAWzGAwdWqXSSv6PFLKRVHQ=; b=jjj06Udl1XFoDdXK/fDAKoskykDt7ZwFD6qEh3e266o4Zc9g+qbtxscfWC/dRj7aEy3+ YwA9iLh9C9JXuWvX5XH6lRvT0NYvxLTH5puWEUz4I7KqN96/ZhW/C0WlEMi++3ujYqmU Dr32sQBMPtWJhTokU/ZdgYTgjNAgogK4/tk= Received: from maileast.thefacebook.com ([163.114.130.16]) by m0001303.ppops.net with ESMTP id 2tbpv82m5v-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 25 Jun 2019 23:12:51 -0700 Received: from mx-out.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 25 Jun 2019 23:12:50 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id 2DEBE861896; Tue, 25 Jun 2019 23:12:48 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrii Nakryiko Smtp-Origin-Hostname: dev101.prn2.facebook.com To: , , , , , CC: Andrii Nakryiko Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 bpf-next 2/3] libbpf: auto-set PERF_EVENT_ARRAY size to number of CPUs Date: Tue, 25 Jun 2019 23:12:34 -0700 Message-ID: <20190626061235.602633-3-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190626061235.602633-1-andriin@fb.com> References: <20190626061235.602633-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-26_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906260074 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org For BPF_MAP_TYPE_PERF_EVENT_ARRAY typically correct size is number of possible CPUs. This is impossible to specify at compilation time. This change adds automatic setting of PERF_EVENT_ARRAY size to number of system CPUs, unless non-zero size is specified explicitly. This allows to adjust size for advanced specific cases, while providing convenient and logical defaults. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index c74cc535902a..8f2b8a081ba7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2114,6 +2114,7 @@ static int bpf_object__create_maps(struct bpf_object *obj) { struct bpf_create_map_attr create_attr = {}; + int nr_cpus = 0; unsigned int i; int err; @@ -2136,7 +2137,21 @@ bpf_object__create_maps(struct bpf_object *obj) create_attr.map_flags = def->map_flags; create_attr.key_size = def->key_size; create_attr.value_size = def->value_size; - create_attr.max_entries = def->max_entries; + if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && + !def->max_entries) { + if (!nr_cpus) + nr_cpus = libbpf_num_possible_cpus(); + if (nr_cpus < 0) { + pr_warning("failed to determine number of system CPUs: %d\n", + nr_cpus); + return nr_cpus; + } + pr_debug("map '%s': setting size to %d\n", + map->name, nr_cpus); + create_attr.max_entries = nr_cpus; + } else { + create_attr.max_entries = def->max_entries; + } create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; -- 2.17.1