From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 108801 invoked by alias); 2 Apr 2018 15:19:54 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 108792 invoked by uid 89); 2 Apr 2018 15:19:53 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,KAM_SHORT,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=lock, Wang, speaker, squeeze X-HELO: mail-qk0-f195.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=s5tR2dzRaUtqBAnXhS7SFOJyHWXu05PL+WhG7R49TXI=; b=VQqZ1Fv2NTG49Nd8YFDOV6fIfZl8SLPCYzrnN5lIS6SEvSY6tLBq+cE75BEkQkmA42 Im5a9MarkrROFzrXs2HdV/PDc1Nqj8i4XNgAMPKf8D2U59jaqNF0iJhY0OTeBTQKpwuK noq46bGCxj4AukZb+4cNVRGYmIGsW/EEqxbJKYdHDVgJ2mrAIjRj1b6xTuTc19N3kvff GALyUG6pB7Be+YU1XvdlKjTPFgn8tfFp/jda/i+gCX2krI40IA7G3MCTeVFWmkhojnEc zouRJaT2B/rQpVTwpXy7qqvIKaxzLzqoswGx1blmvtza/CVmLswhihZYp2vHPHJ3TBXS vhUA== X-Gm-Message-State: ALQs6tA5irWgM0saDAwS4x/5alb8VZv5nE1GNrZVWyJztKwt2ApgnCPP b9wGHIu8bqBLlpDjKqYjozuZU5LnoyY= X-Google-Smtp-Source: AIpwx4+pbgsZhuy2UayZ4ygz5iY6ga3xDGnAIRku2WzNwysLRuuwG4V6tEb5a7CV0l5ryNq1JBq6lQ== X-Received: by 10.55.162.66 with SMTP id l63mr13973705qke.124.1522682389006; Mon, 02 Apr 2018 08:19:49 -0700 (PDT) Subject: Re: [PATCH 1/3] Tunables: Add tunables of spin count for adaptive spin mutex To: libc-alpha@sourceware.org References: <1522394093-9835-1-git-send-email-kemi.wang@intel.com> From: Adhemerval Zanella Openpgp: preference=signencrypt Autocrypt: addr=adhemerval.zanella@linaro.org; keydata= xsFNBFcVGkoBEADiQU2x/cBBmAVf5C2d1xgz6zCnlCefbqaflUBw4hB/bEME40QsrVzWZ5Nq 8kxkEczZzAOKkkvv4pRVLlLn/zDtFXhlcvQRJ3yFMGqzBjofucOrmdYkOGo0uCaoJKPT186L NWp53SACXguFJpnw4ODI64ziInzXQs/rUJqrFoVIlrPDmNv/LUv1OVPKz20ETjgfpg8MNwG6 iMizMefCl+RbtXbIEZ3TE/IaDT/jcOirjv96lBKrc/pAL0h/O71Kwbbp43fimW80GhjiaN2y WGByepnkAVP7FyNarhdDpJhoDmUk9yfwNuIuESaCQtfd3vgKKuo6grcKZ8bHy7IXX1XJj2X/ BgRVhVgMHAnDPFIkXtP+SiarkUaLjGzCz7XkUn4XAGDskBNfbizFqYUQCaL2FdbW3DeZqNIa nSzKAZK7Dm9+0VVSRZXP89w71Y7JUV56xL/PlOE+YKKFdEw+gQjQi0e+DZILAtFjJLoCrkEX w4LluMhYX/X8XP6/C3xW0yOZhvHYyn72sV4yJ1uyc/qz3OY32CRy+bwPzAMAkhdwcORA3JPb kPTlimhQqVgvca8m+MQ/JFZ6D+K7QPyvEv7bQ7M+IzFmTkOCwCJ3xqOD6GjX3aphk8Sr0dq3 4Awlf5xFDAG8dn8Uuutb7naGBd/fEv6t8dfkNyzj6yvc4jpVxwARAQABzUlBZGhlbWVydmFs IFphbmVsbGEgTmV0dG8gKExpbmFybyBWUE4gS2V5KSA8YWRoZW1lcnZhbC56YW5lbGxhQGxp bmFyby5vcmc+wsF3BBMBCAAhBQJXFRpKAhsDBQsJCAcDBRUKCQgLBRYCAwEAAh4BAheAAAoJ EKqx7BSnlIjv0e8P/1YOYoNkvJ+AJcNUaM5a2SA9oAKjSJ/M/EN4Id5Ow41ZJS4lUA0apSXW NjQg3VeVc2RiHab2LIB4MxdJhaWTuzfLkYnBeoy4u6njYcaoSwf3g9dSsvsl3mhtuzm6aXFH /Qsauav77enJh99tI4T+58rp0EuLhDsQbnBic/ukYNv7sQV8dy9KxA54yLnYUFqH6pfH8Lly sTVAMyi5Fg5O5/hVV+Z0Kpr+ZocC1YFJkTsNLAW5EIYSP9ftniqaVsim7MNmodv/zqK0IyDB GLLH1kjhvb5+6ySGlWbMTomt/or/uvMgulz0bRS+LUyOmlfXDdT+t38VPKBBVwFMarNuREU2 69M3a3jdTfScboDd2ck1u7l+QbaGoHZQ8ZNUrzgObltjohiIsazqkgYDQzXIMrD9H19E+8fw kCNUlXxjEgH/Kg8DlpoYJXSJCX0fjMWfXywL6ZXc2xyG/hbl5hvsLNmqDpLpc1CfKcA0BkK+ k8R57fr91mTCppSwwKJYO9T+8J+o4ho/CJnK/jBy1pWKMYJPvvrpdBCWq3MfzVpXYdahRKHI ypk8m4QlRlbOXWJ3TDd/SKNfSSrWgwRSg7XCjSlR7PNzNFXTULLB34sZhjrN6Q8NQZsZnMNs TX8nlGOVrKolnQPjKCLwCyu8PhllU8OwbSMKskcD1PSkG6h3r0AqzsFNBFcVGkoBEACgAdbR Ck+fsfOVwT8zowMiL3l9a2DP3Eeak23ifdZG+8Avb/SImpv0UMSbRfnw/N81IWwlbjkjbGTu oT37iZHLRwYUFmA8fZX0wNDNKQUUTjN6XalJmvhdz9l71H3WnE0wneEM5ahu5V1L1utUWTyh VUwzX1lwJeV3vyrNgI1kYOaeuNVvq7npNR6t6XxEpqPsNc6O77I12XELic2+36YibyqlTJIQ V1SZEbIy26AbC2zH9WqaKyGyQnr/IPbTJ2Lv0dM3RaXoVf+CeK7gB2B+w1hZummD21c1Laua +VIMPCUQ+EM8W9EtX+0iJXxI+wsztLT6vltQcm+5Q7tY+HFUucizJkAOAz98YFucwKefbkTp eKvCfCwiM1bGatZEFFKIlvJ2QNMQNiUrqJBlW9nZp/k7pbG3oStOjvawD9ZbP9e0fnlWJIsj 6c7pX354Yi7kxIk/6gREidHLLqEb/otuwt1aoMPg97iUgDV5mlNef77lWE8vxmlY0FBWIXuZ yv0XYxf1WF6dRizwFFbxvUZzIJp3spAao7jLsQj1DbD2s5+S1BW09A0mI/1DjB6EhNN+4bDB SJCOv/ReK3tFJXuj/HbyDrOdoMt8aIFbe7YFLEExHpSk+HgN05Lg5TyTro8oW7TSMTk+8a5M kzaH4UGXTTBDP/g5cfL3RFPl79ubXwARAQABwsFfBBgBCAAJBQJXFRpKAhsMAAoJEKqx7BSn lIjvI/8P/jg0jl4Tbvg3B5kT6PxJOXHYu9OoyaHLcay6Cd+ZrOd1VQQCbOcgLFbf4Yr+rE9l mYsY67AUgq2QKmVVbn9pjvGsEaz8UmfDnz5epUhDxC6yRRvY4hreMXZhPZ1pbMa6A0a/WOSt AgFj5V6Z4dXGTM/lNManr0HjXxbUYv2WfbNt3/07Db9T+GZkpUotC6iknsTA4rJi6u2ls0W9 1UIvW4o01vb4nZRCj4rni0g6eWoQCGoVDk/xFfy7ZliR5B+3Z3EWRJcQskip/QAHjbLa3pml xAZ484fVxgeESOoaeC9TiBIp0NfH8akWOI0HpBCiBD5xaCTvR7ujUWMvhsX2n881r/hNlR9g fcE6q00qHSPAEgGr1bnFv74/1vbKtjeXLCcRKk3Ulw0bY1OoDxWQr86T2fZGJ/HIZuVVBf3+ gaYJF92GXFynHnea14nFFuFgOni0Mi1zDxYH/8yGGBXvo14KWd8JOW0NJPaCDFJkdS5hu0VY 7vJwKcyHJGxsCLU+Et0mryX8qZwqibJIzu7kUJQdQDljbRPDFd/xmGUFCQiQAncSilYOcxNU EMVCXPAQTteqkvA+gNqSaK1NM9tY0eQ4iJpo+aoX8HAcn4sZzt2pfUB9vQMTBJ2d4+m/qO6+ cFTAceXmIoFsN8+gFN3i8Is3u12u8xGudcBPvpoy4OoG Message-ID: Date: Mon, 02 Apr 2018 15:19:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1522394093-9835-1-git-send-email-kemi.wang@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SW-Source: 2018-04/txt/msg00020.txt.bz2 On 30/03/2018 04:14, Kemi Wang wrote: > This patch does not have any functionality change, we only provide a spin > count tunes for pthread adaptive spin mutex. The tunable > glibc.mutex.spin_count tunes can be used by system adminstrator to squeeze > system performance according to different hardware capability and workload > model. > > This is the preparation work for the next patch, in which the way of > adaptive spin would be changed from an expensive cmpxchg to read while > spinning. > > * elf/dl-tunables.list: Add glibc.mutex.spin_count entry. > * manual/tunables.texi: Add glibc.mutex.spin_count description. > * nptl/Makefile: Add mutex-conf.c for compilation. > * nptl/mutex-conf.h: New file. > * nptl/mutex-conf.c: New file. > > Suggested-by: Andi Kleen > Signed-off-by: Kemi Wang > --- > ChangeLog | 10 ++++++- > elf/dl-tunables.list | 10 +++++++ > manual/tunables.texi | 17 ++++++++++++ > nptl/Makefile | 3 +- > nptl/mutex-conf.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > nptl/mutex-conf.h | 31 +++++++++++++++++++++ > 6 files changed, 147 insertions(+), 2 deletions(-) > create mode 100644 nptl/mutex-conf.c > create mode 100644 nptl/mutex-conf.h > > diff --git a/ChangeLog b/ChangeLog > index 1f98425..472657c 100644 > --- a/ChangeLog > +++ b/ChangeLog > @@ -1,5 +1,13 @@ > -2018-03-29 Florian Weimer > +2018-03-30 Kemi Wang > + > + * elf/dl-tunables.list: Add glibc.mutex.spin_count entry. > + * manual/tunables.texi: Add glibc.mutex.spin_count description. > + * nptl/Makefile: Add mutex-conf.c for compilation. > + * nptl/mutex-conf.h: New file. > + * nptl/mutex-conf.c: New file. > + * nptl/Makefile: Add new file compilation. > > +2018-03-29 Florian Weimer > * sysdeps/unix/sysv/linux/i386/tst-bz21269.c (do_test): Also > capture SIGBUS. > > diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list > index 1f8ecb8..0c27c14 100644 > --- a/elf/dl-tunables.list > +++ b/elf/dl-tunables.list > @@ -121,4 +121,14 @@ glibc { > default: 3 > } > } > + > + mutex { > + spin_count { > + type: INT_32 > + minval: 0 > + maxval: 30000 > + env_alias: LD_SPIN_COUNT > + default: 1000 > + } > + } Indentation seems off here, rest the file uses double space while your patch uses tabs. Also I not sure if it worth to add environment variable for this tunable, I would rather avoid adding newer ones (and naming seems off, since afaik LD_* meaning some parameters that affects the loader). > } > diff --git a/manual/tunables.texi b/manual/tunables.texi > index be33c9f..9c6a9f1 100644 > --- a/manual/tunables.texi > +++ b/manual/tunables.texi > @@ -281,6 +281,23 @@ of try lock attempts. > The default value of this tunable is @samp{3}. > @end deftp > > +@node Pthread Mutex Tunables > +@section Pthread Mutex Tunables > +@cindex pthread mutex tunables > + > +@deftp {Tunable namespace} glibc.mutex > +Behavior of ptherad mutex can be tuned to acquire performance improvement > +according to specific hardware capablity and workload character by setting > +the following tunables in the @code{mutex} namespace. > +@end deftp There is a typo (s/ptherad/pthread) and I think 'acquire' is not the best word here, I would use 'increase' (I am not a native speaker, so someone might suggest a better wording here). > + > +@deftp Tunable glibc.mutex.spin_count > +The @code{glibc.mutex.spin_count} tunable set the maximum times the thread > +should spin on the lock before going to sleep. > + > +The default value of this tunable is @samp{1000}. > +@end deftp I think we need to expand it to specify: * spinning is only used for the mutex initialized with PTHREAD_MUTEX_ADAPTIVE_NP GNU extension(current wording is ambiguous). * It affects both pthread_mutex_lock and pthread_mutex_timedlock. * The spinning is done by first issuing an atomic operation similar to trylock followed by a arch-specific no operation (not sure if we need to expand how spinning is backoff value is incremented). * Not sure 'sleep' is right terminology here, since for Linux 'futex' can return right away when maximum spin_count it reached. > + > @node Hardware Capability Tunables > @section Hardware Capability Tunables > @cindex hardware capability tunables > diff --git a/nptl/Makefile b/nptl/Makefile > index 94be92c..5edacea 100644 > --- a/nptl/Makefile > +++ b/nptl/Makefile > @@ -139,7 +139,8 @@ libpthread-routines = nptl-init vars events version pt-interp \ > pthread_mutex_getprioceiling \ > pthread_mutex_setprioceiling \ > pthread_setname pthread_getname \ > - pthread_setattr_default_np pthread_getattr_default_np > + pthread_setattr_default_np pthread_getattr_default_np \ > + mutex-conf > # pthread_setuid pthread_seteuid pthread_setreuid \ > # pthread_setresuid \ > # pthread_setgid pthread_setegid pthread_setregid \ I think a better name for the file would be pthread_mutex_conf.c. > diff --git a/nptl/mutex-conf.c b/nptl/mutex-conf.c > new file mode 100644 > index 0000000..f4ffd6d > --- /dev/null > +++ b/nptl/mutex-conf.c > @@ -0,0 +1,78 @@ > +/* mutex-conf.c: Pthread mutex tunable parameters. > + Copyright (C) 2013-2018 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + Copyright should start at 2018 for newer implementations. > + 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 > + . */ > + > +#include "config.h" > +#include > +#include > +#include > +#include > + > +#if HAVE_TUNABLES > +# define TUNABLE_NAMESPACE mutex > +#endif > +#include > + > + > +struct mutex_config __mutex_aconf = > + { > + /* The maximum times a thread spin on the lock before > + * going to sleep */ > + .spin_count = 1000, > + }; > + Indentation seems off here and in other places in this file. > +#if HAVE_TUNABLES > +#define TUNABLE_CALLBACK_FNDECL(__name, __type) \ Indentation for nested preprocessor is to just one space each level: #if HAVE_TUNABLES # define ... > +static inline void \ > +__always_inline \ > +do_set_mutex_ ## __name (__type value) \ > +{ \ > + __mutex_aconf.__name = value; \ > +} \ > +void \ > +TUNABLE_CALLBACK (set_mutex_ ## __name) (tunable_val_t *valp) \ > +{ \ > + __type value = (__type) (valp)->numval; \ > + do_set_mutex_ ## __name (value); \ > +} > + > +TUNABLE_CALLBACK_FNDECL (spin_count, int32_t); > +#endif > + > +static void > +mutex_tunables_init (int argc __attribute__ ((unused)), > + char **argv __attribute__ ((unused)), > + char **environ) > +{ > +#if HAVE_TUNABLES > + > + TUNABLE_GET (spin_count, int32_t, > + TUNABLE_CALLBACK (set_mutex_spin_count)); > +#endif > +} > + > +#ifdef SHARED > +# define INIT_SECTION ".init_array" > +#else > +# define INIT_SECTION ".preinit_array" > +#endif > + > +void (*const __pthread_mutex_tunables_init_array []) (int, char **, char **) > + __attribute__ ((section (INIT_SECTION), aligned (sizeof (void *)))) = > +{ > + &mutex_tunables_init > +};> diff --git a/nptl/mutex-conf.h b/nptl/mutex-conf.h > new file mode 100644 > index 0000000..babefe3 > --- /dev/null > +++ b/nptl/mutex-conf.h > @@ -0,0 +1,31 @@ > +/* mutex-conf.h: Pthread mutex tunable parameters. > + Copyright (C) 2013-2018 Free Software Foundation, Inc. Copyright should start at 2018 for newer implementations. > + 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 > + . */ > +#ifndef _MUTEX_CONF_H > +#define _MUTEX_CONF_H 1 > + > +#include > +#include > + > +struct mutex_config > +{ > + int spin_count; > +}; > + > +extern struct mutex_config __mutex_aconf attribute_hidden; > + > +#endif >