From patchwork Fri Nov 13 09:45:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 41040 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 3FDCB3A1B825; Fri, 13 Nov 2020 09:45:23 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 3FDCB3A1B825 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1605260723; bh=Wdp0fMOO2eGQ2RLzDXf11GYbbpncR2t+rkMQ73KOaak=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=MWBr541VHcyDhdLGJTFde6OKEleRbBEqrIInMdkQIovCByhDG9MwQdccEFyqhLNLh hg5VMxV7+yPaGFytNQoN9FZovHq3bCfGBwxgXqee7+cgf2zeJmBebSF5za3EKatpkQ jVpoBG6rZC/JwaOs8n08fAiBhVr4GI0opFW8l4rA= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id D894C3854813 for ; Fri, 13 Nov 2020 09:45:20 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org D894C3854813 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-211-w7vZwio0NdSch_qL9dd5fg-1; Fri, 13 Nov 2020 04:45:16 -0500 X-MC-Unique: w7vZwio0NdSch_qL9dd5fg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 07E7A1018F78 for ; Fri, 13 Nov 2020 09:45:16 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-113-222.ams2.redhat.com [10.36.113.222]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4E9D57512B for ; Fri, 13 Nov 2020 09:45:15 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH] nptl: Eliminate and __is_smp Date: Fri, 13 Nov 2020 10:45:13 +0100 Message-ID: <874kltvbdi.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.2 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Most systems are SMP, so optimizing for the UP case is no longer approriate. A dynamic check based on the kernel identification has been only implemented for i386 anyway. To disable adaptive mutexes on sh, define DEFAULT_ADAPTIVE_COUNT as zero for this architecture. Reviewed-by: Adhemerval Zanella --- nptl/nptl-init.c | 4 -- nptl/pthreadP.h | 3 -- nptl/pthread_mutex_lock.c | 3 -- nptl/pthread_mutex_timedlock.c | 3 -- nptl/smp.h | 27 ------------ nptl/vars.c | 3 -- sysdeps/unix/sysv/linux/i386/smp.h | 55 ------------------------ sysdeps/unix/sysv/linux/sh/adaptive_spin_count.h | 20 +++++++++ sysdeps/unix/sysv/linux/sh/smp.h | 23 ---------- 9 files changed, 20 insertions(+), 121 deletions(-) diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index 95c60a524a..4aa1231bec 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -32,7 +32,6 @@ #include #include #include -#include #include #include #include @@ -346,9 +345,6 @@ __pthread_initialize_minimal_internal (void) __libc_pthread_init (&__fork_generation, __reclaim_stacks, ptr_pthread_functions); - /* Determine whether the machine is SMP or not. */ - __is_smp = is_smp_system (); - #if HAVE_TUNABLES __pthread_tunables_init (); #endif diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index 710b21e890..686f54aa93 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -208,9 +208,6 @@ extern void __default_pthread_attr_freeres (void) attribute_hidden; extern size_t __static_tls_size attribute_hidden; extern size_t __static_tls_align_m1 attribute_hidden; -/* Flag whether the machine is SMP or not. */ -extern int __is_smp attribute_hidden; - /* Thread descriptor handling. */ extern list_t __stack_user; hidden_proto (__stack_user) diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c index 7858abd528..fac774e608 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -120,9 +120,6 @@ __pthread_mutex_lock (pthread_mutex_t *mutex) else if (__builtin_expect (PTHREAD_MUTEX_TYPE (mutex) == PTHREAD_MUTEX_ADAPTIVE_NP, 1)) { - if (! __is_smp) - goto simple; - if (LLL_MUTEX_TRYLOCK (mutex) != 0) { int cnt = 0; diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c index fe9e651f6c..de88e9fc25 100644 --- a/nptl/pthread_mutex_timedlock.c +++ b/nptl/pthread_mutex_timedlock.c @@ -113,9 +113,6 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex, case PTHREAD_MUTEX_ADAPTIVE_NP: - if (! __is_smp) - goto simple; - if (lll_trylock (mutex->__data.__lock) != 0) { int cnt = 0; diff --git a/nptl/smp.h b/nptl/smp.h deleted file mode 100644 index 537e5e945c..0000000000 --- a/nptl/smp.h +++ /dev/null @@ -1,27 +0,0 @@ -/* Determine whether the host has multiple processors. Stub version. - Copyright (C) 1996-2020 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Library General Public License as - published by the Free Software Foundation; either version 2 of the - License, or (at your option) any later version. - - The GNU C Library 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 - Library General Public License for more details. - - You should have received a copy of the GNU Library General Public - License along with the GNU C Library; see the file COPYING.LIB. If - not, see . */ - -/* Test whether the machine has more than one processor. This is not the - best test but good enough. More complicated tests would require `malloc' - which is not available at that time. */ -static inline int -is_smp_system (void) -{ - /* Assume all machines are SMP and/or CMT and/or SMT. */ - return 1; -} diff --git a/nptl/vars.c b/nptl/vars.c index 3696020145..2f52391dc2 100644 --- a/nptl/vars.c +++ b/nptl/vars.c @@ -27,9 +27,6 @@ union pthread_attr_transparent __default_pthread_attr attribute_hidden; /* Mutex protecting __default_pthread_attr. */ int __default_pthread_attr_lock = LLL_LOCK_INITIALIZER; -/* Flag whether the machine is SMP or not. */ -int __is_smp attribute_hidden; - #ifndef TLS_MULTIPLE_THREADS_IN_TCB /* Variable set to a nonzero value either if more than one thread runs or ran, or if a single-threaded process is trying to cancel itself. See diff --git a/sysdeps/unix/sysv/linux/i386/smp.h b/sysdeps/unix/sysv/linux/i386/smp.h deleted file mode 100644 index 85a630d048..0000000000 --- a/sysdeps/unix/sysv/linux/i386/smp.h +++ /dev/null @@ -1,55 +0,0 @@ -/* Determine whether the host has multiple processors. Linux version. - Copyright (C) 1996-2020 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Library General Public License as - published by the Free Software Foundation; either version 2 of the - License, or (at your option) any later version. - - The GNU C Library 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 - Library General Public License for more details. - - You should have received a copy of the GNU Library General Public - License along with the GNU C Library; see the file COPYING.LIB. If - not, see . */ - -#include -#include -#include -#include -#include - -/* Test whether the machine has more than one processor. This is not the - best test but good enough. More complicated tests would require `malloc' - which is not available at that time. */ -static inline int -is_smp_system (void) -{ - union - { - struct utsname uts; - char buf[512]; - } u; - char *cp; - - /* Try reading the number using `sysctl' first. */ - if (__uname (&u.uts) == 0) - cp = u.uts.version; - else - { - /* This was not successful. Now try reading the /proc filesystem. */ - int fd = __open64_nocancel ("/proc/sys/kernel/version", O_RDONLY); - if (__builtin_expect (fd, 0) == -1 - || __read_nocancel (fd, u.buf, sizeof (u.buf)) <= 0) - /* This also didn't work. We give up and say it's a UP machine. */ - u.buf[0] = '\0'; - - __close_nocancel_nostatus (fd); - cp = u.buf; - } - - return strstr (cp, "SMP") != NULL; -} diff --git a/sysdeps/unix/sysv/linux/sh/adaptive_spin_count.h b/sysdeps/unix/sysv/linux/sh/adaptive_spin_count.h new file mode 100644 index 0000000000..3431cd3d8c --- /dev/null +++ b/sysdeps/unix/sysv/linux/sh/adaptive_spin_count.h @@ -0,0 +1,20 @@ +/* Maximum adaptive spin count default for sh. + Copyright (C) 2020 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +/* Disable spinning because sh is always uniprocessor. */ +#define DEFAULT_ADAPTIVE_COUNT 0 diff --git a/sysdeps/unix/sysv/linux/sh/smp.h b/sysdeps/unix/sysv/linux/sh/smp.h deleted file mode 100644 index 55efedc0ba..0000000000 --- a/sysdeps/unix/sysv/linux/sh/smp.h +++ /dev/null @@ -1,23 +0,0 @@ -/* Determine whether the host has multiple processors. SH version. - Copyright (C) 2002-2020 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Library General Public License as - published by the Free Software Foundation; either version 2 of the - License, or (at your option) any later version. - - The GNU C Library 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 - Library General Public License for more details. - - You should have received a copy of the GNU Library General Public - License along with the GNU C Library; see the file COPYING.LIB. If - not, see . */ - -static inline int -is_smp_system (void) -{ - return 0; -}