From patchwork Thu Feb 28 23:31:23 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1049870 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="hQIL/UhC"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 449TMr2K3Jz9s4V for ; Fri, 1 Mar 2019 10:31:36 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731853AbfB1Xbe (ORCPT ); Thu, 28 Feb 2019 18:31:34 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:37354 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731324AbfB1Xbd (ORCPT ); Thu, 28 Feb 2019 18:31:33 -0500 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.27/8.16.0.27) with SMTP id x1SNSZwh002203 for ; Thu, 28 Feb 2019 15:31:32 -0800 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=9i1lDDyiX6EYz4yom4CayHQJIy/EVoB//AM7hzboX+Y=; b=hQIL/UhCpTx/g3J+cH+P8vjP7cEY93pto7noJQkUEQlRfxEJPLQfQ4s55GKfcfjTfem/ MXiZMP2WquPNKWhnhCyso4/o1IE4+uQAhFZDvg53V8UuaOfRQdcgXweQgvqpDZTlmV6e bDWReDEgN3KkFLqb51uiVpq/+JXt02OVys8= Received: from maileast.thefacebook.com ([199.201.65.23]) by m0089730.ppops.net with ESMTP id 2qxrh085ca-11 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Thu, 28 Feb 2019 15:31:31 -0800 Received: from mx-out.facebook.com (2620:10d:c0a1:3::13) by mail.thefacebook.com (2620:10d:c021:18::171) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Thu, 28 Feb 2019 15:31:28 -0800 Received: by devvm7221.prn2.facebook.com (Postfix, from userid 137359) id D1921C155DDE; Thu, 28 Feb 2019 15:31:26 -0800 (PST) Smtp-Origin-Hostprefix: devvm From: Andrii Nakryiko Smtp-Origin-Hostname: devvm7221.prn2.facebook.com To: , , , , , , , CC: Andrii Nakryiko Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 bpf-next 3/5] btf: allow to customize dedup hash table size Date: Thu, 28 Feb 2019 15:31:23 -0800 Message-ID: <20190228233125.1013080-4-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190228233125.1013080-1-andriin@fb.com> References: <20190228233125.1013080-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-02-28_15:, , signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Default size of dedup table (16k) is good enough for most binaries, even typical vmlinux images. But there are cases of binaries with huge amount of BTF types (e.g., allyesconfig variants of kernel), which benefit from having bigger dedup table size to lower amount of unnecessary hash collisions. Tools like pahole, thus, can tune this parameter to reach optimal performance. This change also serves double purpose of allowing tests to force hash collisions to test some corner cases, used in follow up patch. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/lib/bpf/btf.c | 53 ++++++++++++++++++++++++++++++--------------- tools/lib/bpf/btf.h | 1 + 2 files changed, 37 insertions(+), 17 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 68b50e9bbde1..0f83f99211c6 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1070,8 +1070,8 @@ int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, return err; } -#define BTF_DEDUP_TABLE_SIZE_LOG 14 -#define BTF_DEDUP_TABLE_MOD ((1 << BTF_DEDUP_TABLE_SIZE_LOG) - 1) +#define BTF_DEDUP_TABLE_DEFAULT_SIZE (1 << 14) +#define BTF_DEDUP_TABLE_MAX_SIZE_LOG 31 #define BTF_UNPROCESSED_ID ((__u32)-1) #define BTF_IN_PROGRESS_ID ((__u32)-2) @@ -1128,18 +1128,21 @@ static inline __u32 hash_combine(__u32 h, __u32 value) #undef GOLDEN_RATIO_PRIME } -#define for_each_hash_node(table, hash, node) \ - for (node = table[hash & BTF_DEDUP_TABLE_MOD]; node; node = node->next) +#define for_each_dedup_cand(d, hash, node) \ + for (node = d->dedup_table[hash & (d->opts.dedup_table_size - 1)]; \ + node; \ + node = node->next) static int btf_dedup_table_add(struct btf_dedup *d, __u32 hash, __u32 type_id) { struct btf_dedup_node *node = malloc(sizeof(struct btf_dedup_node)); + int bucket = hash & (d->opts.dedup_table_size - 1); if (!node) return -ENOMEM; node->type_id = type_id; - node->next = d->dedup_table[hash & BTF_DEDUP_TABLE_MOD]; - d->dedup_table[hash & BTF_DEDUP_TABLE_MOD] = node; + node->next = d->dedup_table[bucket]; + d->dedup_table[bucket] = node; return 0; } @@ -1177,7 +1180,7 @@ static void btf_dedup_table_free(struct btf_dedup *d) if (!d->dedup_table) return; - for (i = 0; i < (1 << BTF_DEDUP_TABLE_SIZE_LOG); i++) { + for (i = 0; i < d->opts.dedup_table_size; i++) { while (d->dedup_table[i]) { tmp = d->dedup_table[i]; d->dedup_table[i] = tmp->next; @@ -1212,19 +1215,37 @@ static void btf_dedup_free(struct btf_dedup *d) free(d); } +/* Find closest power of two >= to size, capped at 2^max_size_log */ +static __u32 roundup_pow2_max(__u32 size, int max_size_log) +{ + int i; + + for (i = 0; i < max_size_log && (1U << i) < size; i++) + ; + return 1U << i; +} + + static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, const struct btf_dedup_opts *opts) { struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup)); int i, err = 0; + __u32 sz; if (!d) return ERR_PTR(-ENOMEM); + d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds; + sz = opts && opts->dedup_table_size ? opts->dedup_table_size + : BTF_DEDUP_TABLE_DEFAULT_SIZE; + sz = roundup_pow2_max(sz, BTF_DEDUP_TABLE_MAX_SIZE_LOG); + d->opts.dedup_table_size = sz; + d->btf = btf; d->btf_ext = btf_ext; - d->dedup_table = calloc(1 << BTF_DEDUP_TABLE_SIZE_LOG, + d->dedup_table = calloc(d->opts.dedup_table_size, sizeof(struct btf_dedup_node *)); if (!d->dedup_table) { err = -ENOMEM; @@ -1249,8 +1270,6 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, for (i = 0; i <= btf->nr_types; i++) d->hypot_map[i] = BTF_UNPROCESSED_ID; - d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds; - done: if (err) { btf_dedup_free(d); @@ -1824,7 +1843,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_INT: h = btf_hash_int(t); - for_each_hash_node(d->dedup_table, h, cand_node) { + for_each_dedup_cand(d, h, cand_node) { cand = d->btf->types[cand_node->type_id]; if (btf_equal_int(t, cand)) { new_id = cand_node->type_id; @@ -1835,7 +1854,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_ENUM: h = btf_hash_enum(t); - for_each_hash_node(d->dedup_table, h, cand_node) { + for_each_dedup_cand(d, h, cand_node) { cand = d->btf->types[cand_node->type_id]; if (btf_equal_enum(t, cand)) { new_id = cand_node->type_id; @@ -1846,7 +1865,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_FWD: h = btf_hash_common(t); - for_each_hash_node(d->dedup_table, h, cand_node) { + for_each_dedup_cand(d, h, cand_node) { cand = d->btf->types[cand_node->type_id]; if (btf_equal_common(t, cand)) { new_id = cand_node->type_id; @@ -2263,7 +2282,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) return 0; h = btf_hash_struct(t); - for_each_hash_node(d->dedup_table, h, cand_node) { + for_each_dedup_cand(d, h, cand_node) { int eq; btf_dedup_clear_hypot_map(d); @@ -2349,7 +2368,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) t->type = ref_type_id; h = btf_hash_common(t); - for_each_hash_node(d->dedup_table, h, cand_node) { + for_each_dedup_cand(d, h, cand_node) { cand = d->btf->types[cand_node->type_id]; if (btf_equal_common(t, cand)) { new_id = cand_node->type_id; @@ -2372,7 +2391,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) info->index_type = ref_type_id; h = btf_hash_array(t); - for_each_hash_node(d->dedup_table, h, cand_node) { + for_each_dedup_cand(d, h, cand_node) { cand = d->btf->types[cand_node->type_id]; if (btf_equal_array(t, cand)) { new_id = cand_node->type_id; @@ -2403,7 +2422,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) } h = btf_hash_fnproto(t); - for_each_hash_node(d->dedup_table, h, cand_node) { + for_each_dedup_cand(d, h, cand_node) { cand = d->btf->types[cand_node->type_id]; if (btf_equal_fnproto(t, cand)) { new_id = cand_node->type_id; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index b60bb7cf5fff..28a1e1e59861 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -90,6 +90,7 @@ LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); struct btf_dedup_opts { + unsigned int dedup_table_size; bool dont_resolve_fwds; };