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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 48790C43331 for ; Thu, 26 Mar 2020 10:09:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2350C2070A for ; Thu, 26 Mar 2020 10:09:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726270AbgCZKJ0 (ORCPT ); Thu, 26 Mar 2020 06:09:26 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:50196 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727773AbgCZKIm (ORCPT ); Thu, 26 Mar 2020 06:08:42 -0400 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jHPRE-00047J-AV; Thu, 26 Mar 2020 11:08:36 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id DEBB51C0478; Thu, 26 Mar 2020 11:08:35 +0100 (CET) Date: Thu, 26 Mar 2020 10:08:35 -0000 From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: core/objtool] objtool: Optimize find_section_by_name() Cc: "Peter Zijlstra (Intel)" , Miroslav Benes , Josh Poimboeuf , x86 , LKML In-Reply-To: <20200324160924.440174280@infradead.org> References: <20200324160924.440174280@infradead.org> MIME-Version: 1.0 Message-ID: <158521731555.28353.11326523921308261337.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the core/objtool branch of tip: Commit-ID: ae358196fac3a0b4d2a7d47a4f401e3421027b03 Gitweb: https://git.kernel.org/tip/ae358196fac3a0b4d2a7d47a4f401e3421027b03 Author: Peter Zijlstra AuthorDate: Thu, 12 Mar 2020 09:32:10 +01:00 Committer: Peter Zijlstra CommitterDate: Wed, 25 Mar 2020 18:28:29 +01:00 objtool: Optimize find_section_by_name() In order to avoid yet another linear search of (20k) sections, add a name based hash. This reduces objtool runtime on vmlinux.o by some 10s to around 35s. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200324160924.440174280@infradead.org --- tools/objtool/elf.c | 10 +++++++++- tools/objtool/elf.h | 3 +++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index 9007713..20fe40d 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -22,11 +22,16 @@ #define MAX_NAME_LEN 128 +static inline u32 str_hash(const char *str) +{ + return jhash(str, strlen(str), 0); +} + struct section *find_section_by_name(struct elf *elf, const char *name) { struct section *sec; - list_for_each_entry(sec, &elf->sections, list) + hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name)) if (!strcmp(sec->name, name)) return sec; @@ -202,6 +207,7 @@ static int read_sections(struct elf *elf) list_add_tail(&sec->list, &elf->sections); hash_add(elf->section_hash, &sec->hash, sec->idx); + hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); } if (stats) @@ -441,6 +447,7 @@ struct elf *elf_read(const char *name, int flags) hash_init(elf->symbol_hash); hash_init(elf->section_hash); + hash_init(elf->section_name_hash); INIT_LIST_HEAD(&elf->sections); elf->fd = open(name, flags); @@ -581,6 +588,7 @@ struct section *elf_create_section(struct elf *elf, const char *name, list_add_tail(&sec->list, &elf->sections); hash_add(elf->section_hash, &sec->hash, sec->idx); + hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); return sec; } diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h index 8c272eb..ac7c46f 100644 --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -10,6 +10,7 @@ #include #include #include +#include #ifdef LIBELF_USE_DEPRECATED # define elf_getshdrnum elf_getshnum @@ -26,6 +27,7 @@ struct section { struct list_head list; struct hlist_node hash; + struct hlist_node name_hash; GElf_Shdr sh; struct list_head symbol_list; struct list_head rela_list; @@ -73,6 +75,7 @@ struct elf { struct list_head sections; DECLARE_HASHTABLE(symbol_hash, 20); DECLARE_HASHTABLE(section_hash, 16); + DECLARE_HASHTABLE(section_name_hash, 16); };