From patchwork Tue Oct 1 20:12:25 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Tromey X-Patchwork-Id: 34775 Received: (qmail 42053 invoked by alias); 1 Oct 2019 20:12:43 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 41908 invoked by uid 89); 1 Oct 2019 20:12:42 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-21.3 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_PASS autolearn=ham version=3.3.1 spammy= X-HELO: gateway22.websitewelcome.com Received: from gateway22.websitewelcome.com (HELO gateway22.websitewelcome.com) (192.185.47.168) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 01 Oct 2019 20:12:38 +0000 Received: from cm12.websitewelcome.com (cm12.websitewelcome.com [100.42.49.8]) by gateway22.websitewelcome.com (Postfix) with ESMTP id DBD9E6AE78 for ; Tue, 1 Oct 2019 15:12:36 -0500 (CDT) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with SMTP id FOVgi8V4gW4frFOVgip3Eg; Tue, 01 Oct 2019 15:12:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tromey.com; s=default; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Sender:Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=CeqN/OP5zMehmIUqZkF1rp6tl0ZYhYhjI5d63tuiQ6M=; b=X4rxNl2Ms3FYXpik5tZPHvBd+N 9I9o9S/94ahODPvWg4/FLS0eRkejUWX6iWajbsB/u84RIFZgBMhkuigzph3+ci4KBAIfUNTIivcVL 63N1F3C5kVPBxJr6LsbCBf/kZ; Received: from 75-166-72-156.hlrn.qwest.net ([75.166.72.156]:47310 helo=bapiya.Home) by box5379.bluehost.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92) (envelope-from ) id 1iFOVg-0023p5-Gm; Tue, 01 Oct 2019 14:12:36 -0600 From: Tom Tromey To: gdb-patches@sourceware.org Cc: Tom Tromey Subject: [PATCH v4 09/11] Demangle minsyms in parallel Date: Tue, 1 Oct 2019 14:12:25 -0600 Message-Id: <20191001201227.8519-10-tom@tromey.com> In-Reply-To: <20191001201227.8519-1-tom@tromey.com> References: <20191001201227.8519-1-tom@tromey.com> This patch introduces a simple parallel for_each and changes the minimal symbol reader to use it when computing the demangled name for a minimal symbol. This yields a speedup when reading minimal symbols. gdb/ChangeLog 2019-10-01 Tom Tromey * minsyms.c (minimal_symbol_reader::install): Use parallel_for_each. * gdbsupport/parallel-for.h: New file. * gdbsupport/parallel-for.c: New file. * Makefile.in (HFILES_NO_SRCDIR): Add gdbsupport/parallel-for.h. (COMMON_SFILES): Add gdbsupport/parallel-for.c. --- gdb/ChangeLog | 9 +++ gdb/Makefile.in | 2 + gdb/gdbsupport/parallel-for.c | 27 +++++++++ gdb/gdbsupport/parallel-for.h | 101 ++++++++++++++++++++++++++++++++++ gdb/minsyms.c | 31 +++++++---- 5 files changed, 160 insertions(+), 10 deletions(-) create mode 100644 gdb/gdbsupport/parallel-for.c create mode 100644 gdb/gdbsupport/parallel-for.h diff --git a/gdb/Makefile.in b/gdb/Makefile.in index d4eca61d06e..c7b9efdbbc6 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -970,6 +970,7 @@ COMMON_SFILES = \ gdbsupport/gdb_vecs.c \ gdbsupport/netstuff.c \ gdbsupport/new-op.c \ + gdbsupport/parallel-for.c \ gdbsupport/pathstuff.c \ gdbsupport/print-utils.c \ gdbsupport/ptid.c \ @@ -1469,6 +1470,7 @@ HFILES_NO_SRCDIR = \ gdbsupport/common-inferior.h \ gdbsupport/netstuff.h \ gdbsupport/host-defs.h \ + gdbsupport/parallel-for.h \ gdbsupport/pathstuff.h \ gdbsupport/print-utils.h \ gdbsupport/ptid.h \ diff --git a/gdb/gdbsupport/parallel-for.c b/gdb/gdbsupport/parallel-for.c new file mode 100644 index 00000000000..0024278bd7f --- /dev/null +++ b/gdb/gdbsupport/parallel-for.c @@ -0,0 +1,27 @@ +/* Parallel for loops + + Copyright (C) 2019 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#include "gdbsupport/common-defs.h" +#include "gdbsupport/parallel-for.h" + +namespace gdb +{ +/* See parallel-for.h. */ +int max_threads = -1; +} diff --git a/gdb/gdbsupport/parallel-for.h b/gdb/gdbsupport/parallel-for.h new file mode 100644 index 00000000000..60b9472e1fe --- /dev/null +++ b/gdb/gdbsupport/parallel-for.h @@ -0,0 +1,101 @@ +/* Parallel for loops + + Copyright (C) 2019 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#ifndef GDBSUPPORT_PARALLEL_FOR_H +#define GDBSUPPORT_PARALLEL_FOR_H + +#include +#if CXX_STD_THREAD +#include +#include +#endif + +#include "gdbsupport/block-signals.h" + +namespace gdb +{ + +/* True if threading should be enabled. */ + +extern int max_threads; + +/* A very simple "parallel for". This splits the range of iterators + into subranges, and then passes each subrange to the callback. The + work may or may not be done in separate threads. + + This approach was chosen over having the callback work on single + items because it makes it simple for the caller to do + once-per-subrange initialization and destruction. */ + +template +void +parallel_for_each (RandomIt first, RandomIt last, RangeFunction callback) +{ +#if CXX_STD_THREAD + int n_threads = std::thread::hardware_concurrency (); + /* So we can use a local array below. */ + const int local_max = 16; + /* Be sure to handle the "unlimited" case. */ + if (max_threads >= 0 && n_threads > max_threads) + n_threads = max_threads; + if (n_threads > local_max) + n_threads = local_max; + int n_actual_threads = 0; + + std::thread threads[local_max]; + size_t n_elements = last - first; + if (n_threads > 1 && 2 * n_threads <= n_elements) + { + /* Ensure that signals used by gdb are blocked in the new + threads. */ + block_signals blocker; + + size_t elts_per_thread = n_elements / n_threads; + n_actual_threads = n_threads - 1; + for (int i = 0; i < n_actual_threads; ++i) + { + RandomIt end = first + elts_per_thread; + try + { + threads[i] = std::thread (callback, first, end); + } + catch (const std::system_error &failure) + { + /* If a thread failed to start, ignore it and fall back + to processing in the main thread. */ + n_actual_threads = i; + break; + } + first = end; + } + } +#endif /* CXX_STD_THREAD */ + + /* Process all the remaining elements in the main thread. */ + callback (first, last); + +#if CXX_STD_THREAD + for (int i = 0; i < n_actual_threads; ++i) + threads[i].join (); +#endif /* CXX_STD_THREAD */ +} + +} + +#endif /* GDBSUPPORT_PARALLEL_FOR_H */ diff --git a/gdb/minsyms.c b/gdb/minsyms.c index 2b259d39c11..84bf2bb61e2 100644 --- a/gdb/minsyms.c +++ b/gdb/minsyms.c @@ -53,6 +53,8 @@ #include "gdbsupport/symbol.h" #include #include "safe-ctype.h" +#include "gdbsupport/alt-stack.h" +#include "gdbsupport/parallel-for.h" /* See minsyms.h. */ @@ -1332,16 +1334,25 @@ minimal_symbol_reader::install () m_objfile->per_bfd->msymbols = std::move (msym_holder); msymbols = m_objfile->per_bfd->msymbols.get (); - for (int i = 0; i < mcount; ++i) - { - if (!msymbols[i].name_set) - { - symbol_set_names (&msymbols[i], msymbols[i].name, - strlen (msymbols[i].name), 0, - m_objfile->per_bfd); - msymbols[i].name_set = 1; - } - } + gdb::parallel_for_each + (&msymbols[0], &msymbols[mcount], + [&] (minimal_symbol *start, minimal_symbol *end) + { + /* Ensure that SIGSEGV is delivered to an alternate signal + stack. */ + gdb::alternate_signal_stack signal_stack; + + for (minimal_symbol *msym = start; msym < end; ++msym) + { + if (!msym->name_set) + { + symbol_set_names (msym, msym->name, + strlen (msym->name), 0, + m_objfile->per_bfd); + msym->name_set = 1; + } + } + }); build_minimal_symbol_hash_tables (m_objfile); }