diff options
-rw-r--r-- | ChangeLog | 18 | ||||
-rw-r--r-- | manual/tunables.texi | 27 | ||||
-rw-r--r-- | nptl/Makefile | 2 | ||||
-rw-r--r-- | nptl/nptl-init.c | 5 | ||||
-rw-r--r-- | nptl/pthreadP.h | 11 | ||||
-rw-r--r-- | nptl/pthread_mutex_conf.c | 46 | ||||
-rw-r--r-- | nptl/pthread_mutex_conf.h | 34 | ||||
-rw-r--r-- | nptl/pthread_mutex_lock.c | 2 | ||||
-rw-r--r-- | nptl/pthread_mutex_timedlock.c | 2 | ||||
-rw-r--r-- | sysdeps/generic/adaptive_spin_count.h | 22 | ||||
-rw-r--r-- | sysdeps/nptl/dl-tunables.list | 27 |
11 files changed, 190 insertions, 6 deletions
@@ -1,3 +1,21 @@ +2018-12-01 Kemi Wang <kemi.wang@intel.com> + + * manual/tunables.texi (POSIX Thread Tunables): New node. + * nptl/Makefile (libpthread-routines): Add pthread_mutex_conf. + * nptl/nptl-init.c: Include pthread_mutex_conf.h + (__pthread_initialize_minimal_internal) [HAVE_TUNABLES]: Call + __pthread_tunables_init. + * nptl/pthreadP.h (MAX_ADAPTIVE_COUNT): Remove. + (max_adaptive_count): Define. + * nptl/pthread_mutex_conf.c: New file. + * nptl/pthread_mutex_conf.h: New file. + * sysdeps/generic/adaptive_spin_count.h: New file. + * sysdeps/nptl/dl-tunables.list: New file. + * nptl/pthread_mutex_lock.c (__pthread_mutex_lock): Use + max_adaptive_count () not MAX_ADAPTIVE_COUNT. + * nptl/pthread_mutex_timedlock.c (__pthrad_mutex_timedlock): + Likewise. + 2018-12-01 Paul Pluzhnikov <ppluzhnikov@google.com> [BZ #20544] diff --git a/manual/tunables.texi b/manual/tunables.texi index 3345a23969..09a25655ae 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -32,6 +32,7 @@ their own namespace. * Tunable names:: The structure of a tunable name * Memory Allocation Tunables:: Tunables in the memory allocation subsystem * Elision Tunables:: Tunables in elision subsystem +* POSIX Thread Tunables:: Tunables in the POSIX thread subsystem * Hardware Capability Tunables:: Tunables that modify the hardware capabilities seen by @theglibc{} @end menu @@ -281,6 +282,32 @@ of try lock attempts. The default value of this tunable is @samp{3}. @end deftp +@node POSIX Thread Tunables +@section POSIX Thread Tunables +@cindex pthread mutex tunables +@cindex thread mutex tunables +@cindex mutex tunables +@cindex tunables thread mutex + +@deftp {Tunable namespace} glibc.pthread +The behavior of POSIX threads can be tuned to gain performance improvements +according to specific hardware capabilities and workload characteristics by +setting the following tunables in the @code{pthread} namespace: +@end deftp + +@deftp Tunable glibc.pthread.mutex_spin_count +The @code{glibc.pthread.mutex_spin_count} tunable sets the maximum number of times +a thread should spin on the lock before calling into the kernel to block. +Adaptive spin is used for mutexes initialized with the +@code{PTHREAD_MUTEX_ADAPTIVE_NP} GNU extension. It affects both +@code{pthread_mutex_lock} and @code{pthread_mutex_timedlock}. + +The thread spins until either the maximum spin count is reached or the lock +is acquired. + +The default value of this tunable is @samp{100}. +@end deftp + @node Hardware Capability Tunables @section Hardware Capability Tunables @cindex hardware capability tunables diff --git a/nptl/Makefile b/nptl/Makefile index 98b0aa01c7..34ae830276 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -145,7 +145,7 @@ libpthread-routines = nptl-init nptlfreeres vars events version pt-interp \ mtx_destroy mtx_init mtx_lock mtx_timedlock \ mtx_trylock mtx_unlock call_once cnd_broadcast \ cnd_destroy cnd_init cnd_signal cnd_timedwait cnd_wait \ - tss_create tss_delete tss_get tss_set + tss_create tss_delete tss_get tss_set pthread_mutex_conf # pthread_setuid pthread_seteuid pthread_setreuid \ # pthread_setresuid \ # pthread_setgid pthread_setegid pthread_setregid \ diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index 907411d5bc..20ff3fd559 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -38,6 +38,7 @@ #include <kernel-features.h> #include <libc-pointer-arith.h> #include <pthread-pids.h> +#include <pthread_mutex_conf.h> #ifndef TLS_MULTIPLE_THREADS_IN_TCB /* Pointer to the corresponding variable in libc. */ @@ -431,6 +432,10 @@ __pthread_initialize_minimal_internal (void) /* Determine whether the machine is SMP or not. */ __is_smp = is_smp_system (); + +#if HAVE_TUNABLES + __pthread_tunables_init (); +#endif } strong_alias (__pthread_initialize_minimal_internal, __pthread_initialize_minimal) diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index 19efe1e35f..7f16ba9800 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -33,6 +33,7 @@ #include <kernel-features.h> #include <errno.h> #include <internal-signals.h> +#include "pthread_mutex_conf.h" /* Atomic operations on TLS memory. */ @@ -47,10 +48,14 @@ #endif -/* Adaptive mutex definitions. */ -#ifndef MAX_ADAPTIVE_COUNT -# define MAX_ADAPTIVE_COUNT 100 +static inline short max_adaptive_count (void) +{ +#if HAVE_TUNABLES + return __mutex_aconf.spin_count; +#else + return DEFAULT_ADAPTIVE_COUNT; #endif +} /* Magic cookie representing robust mutex with dead owner. */ diff --git a/nptl/pthread_mutex_conf.c b/nptl/pthread_mutex_conf.c new file mode 100644 index 0000000000..545e05b360 --- /dev/null +++ b/nptl/pthread_mutex_conf.c @@ -0,0 +1,46 @@ +/* Pthread mutex tunable parameters. + Copyright (C) 2018 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 + <http://www.gnu.org/licenses/>. */ + +#if HAVE_TUNABLES +# define TUNABLE_NAMESPACE pthread +#include <pthread_mutex_conf.h> +#include <stdint.h> +#include <stdbool.h> +#include <unistd.h> /* Get STDOUT_FILENO for _dl_printf. */ +#include <elf/dl-tunables.h> + +struct mutex_config __mutex_aconf = +{ + /* The maximum number of times a thread should spin on the lock before + calling into kernel to block. */ + .spin_count = DEFAULT_ADAPTIVE_COUNT, +}; + +static void +TUNABLE_CALLBACK (set_mutex_spin_count) (tunable_val_t *valp) +{ + __mutex_aconf.spin_count = (int32_t) (valp)->numval; +} + +void +__pthread_tunables_init (void) +{ + TUNABLE_GET (mutex_spin_count, int32_t, + TUNABLE_CALLBACK (set_mutex_spin_count)); +} +#endif diff --git a/nptl/pthread_mutex_conf.h b/nptl/pthread_mutex_conf.h new file mode 100644 index 0000000000..514d1052c0 --- /dev/null +++ b/nptl/pthread_mutex_conf.h @@ -0,0 +1,34 @@ +/* Pthread mutex tunable parameters. + Copyright (C) 2018 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 + <http://www.gnu.org/licenses/>. */ +#ifndef _PTHREAD_MUTEX_CONF_H +#define _PTHREAD_MUTEX_CONF_H 1 + +#include <adaptive_spin_count.h> + +#if HAVE_TUNABLES +struct mutex_config +{ + int spin_count; +}; + +extern struct mutex_config __mutex_aconf attribute_hidden; + +extern void __pthread_tunables_init (void) attribute_hidden; +#endif + +#endif diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c index 29cc143e6c..474b4df765 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -126,7 +126,7 @@ __pthread_mutex_lock (pthread_mutex_t *mutex) if (LLL_MUTEX_TRYLOCK (mutex) != 0) { int cnt = 0; - int max_cnt = MIN (MAX_ADAPTIVE_COUNT, + int max_cnt = MIN (max_adaptive_count (), mutex->__data.__spins * 2 + 10); do { diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c index 888c12fe28..453b824030 100644 --- a/nptl/pthread_mutex_timedlock.c +++ b/nptl/pthread_mutex_timedlock.c @@ -118,7 +118,7 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex, if (lll_trylock (mutex->__data.__lock) != 0) { int cnt = 0; - int max_cnt = MIN (MAX_ADAPTIVE_COUNT, + int max_cnt = MIN (max_adaptive_count (), mutex->__data.__spins * 2 + 10); do { diff --git a/sysdeps/generic/adaptive_spin_count.h b/sysdeps/generic/adaptive_spin_count.h new file mode 100644 index 0000000000..6b30a2af81 --- /dev/null +++ b/sysdeps/generic/adaptive_spin_count.h @@ -0,0 +1,22 @@ +/* Maximum adaptive spin count by default + Copyright (C) 2018 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 + <http://www.gnu.org/licenses/>. */ + +/* The choice of 100 spins for the default spin count for an adaptive spin + is a completely arbitrary choice that has not been evaluated thoroughly + using modern hardware. */ +#define DEFAULT_ADAPTIVE_COUNT 100 diff --git a/sysdeps/nptl/dl-tunables.list b/sysdeps/nptl/dl-tunables.list new file mode 100644 index 0000000000..beebd5a9a4 --- /dev/null +++ b/sysdeps/nptl/dl-tunables.list @@ -0,0 +1,27 @@ +# Copyright (C) 2018 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 +# <http://www.gnu.org/licenses/>. + +glibc { + pthread { + mutex_spin_count { + type: INT_32 + minval: 0 + maxval: 32767 + default: 100 + } + } +} |