[v3,1/3] Tunables: Add tunables of spin count for pthread adaptive spin mutex
Commit Message
Hi, Maintainers
OK for master branch for this updated V3 patch series?
-----Original Message-----
From: libc-alpha-owner@sourceware.org [mailto:libc-alpha-owner@sourceware.org] On Behalf Of Kemi Wang
Sent: Wednesday, May 23, 2018 5:23 PM
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>; Florian Weimer <fweimer@redhat.com>; Rical Jason <rj@2c3t.io>; Carlos Donell <carlos@redhat.com>; Glibc alpha <libc-alpha@sourceware.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>; Chen, Tim C <tim.c.chen@intel.com>; Kleen, Andi <andi.kleen@intel.com>; Huang, Ying <ying.huang@intel.com>; Lu, Aaron <aaron.lu@intel.com>; Li, Aubrey <aubrey.li@intel.com>; Wang, Kemi <kemi.wang@intel.com>
Subject: [PATCH v3 1/3] Tunables: Add tunables of spin count for pthread adaptive spin mutex
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 administrator to squeeze system performance according to different hardware capabilities and workload characteristics.
The maximum value of spin count is limited to 30000 to avoid the overflow of mutex->__data.__spins variable with the possible type of short in pthread_mutex_lock ().
The default value of spin count is set to 100 with the reference to the previous number of times of spinning via trylock. This value would be architecture-specific and can be tuned with kinds of benchmarks to fit most cases in future.
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 pthread_mutex_conf.c for compilation.
* nptl/pthread_mutex_conf.h: New file.
* nptl/pthread_mutex_conf.c: New file.
ChangeLog:
V2->V3
a) Polish the description of glibc.mutex.spin_count tunable with the
help from Rical Jasan.
b) Get rid of the TUNABLE_CALLBACK_FNDECL macros in
pthread_mutex_conf.c, as suggested by Florian Weimer.
c) Adjust the default value of spin count to 100 with the reference of
the previous spinning way via trylock.
V1->V2
a) Renamed nptl/mutex-conf.h -> nptl/pthread_mutex_conf.h
b) Renamed nptl/mutex-conf.c -> nptl/pthread_mutex_conf.c
c) Change the Makefile to compile pthread_mutex_conf.c
d) Modify the copyright "2013-2018" -> "2018" for new added files
e) Fix the indentation issue (tab -> double space) in
elf/dl-tunables.list
f) Remove the env alias LD_SPIN_COUNT in elf/dl-tunables.list
g) Fix the typo errors and refresh glibc.mutex.spin_count tunable
description in manual/tunables.texi.
h) Fix the indentation issue in nptl/pthread_mutex_conf.c
i) Fix the indentation issue for nested preprocessor (add one space for
each level)
Suggested-by: Andi Kleen <andi.kleen@intel.com>
Signed-off-by: Kemi Wang <kemi.wang@intel.com>
---
ChangeLog | 8 +++++
elf/dl-tunables.list | 9 ++++++
manual/tunables.texi | 22 ++++++++++++++
nptl/Makefile | 3 +-
nptl/pthread_mutex_conf.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++
nptl/pthread_mutex_conf.h | 31 ++++++++++++++++++++
6 files changed, 146 insertions(+), 1 deletion(-) create mode 100644 nptl/pthread_mutex_conf.c create mode 100644 nptl/pthread_mutex_conf.h
--
2.7.4
Comments
Just soft PING. Anything required at my side(e.g. make this change opt-in for x86 architecture).
Thanks for comments.
https://sourceware.org/ml/libc-alpha/2018-05/msg00750.html
https://sourceware.org/ml/libc-alpha/2018-05/msg00752.html
https://sourceware.org/ml/libc-alpha/2018-05/msg00751.html
On 2018年05月25日 16:51, Wang, Kemi wrote:
> Hi, Maintainers
> OK for master branch for this updated V3 patch series?
>
> -----Original Message-----
> From: libc-alpha-owner@sourceware.org [mailto:libc-alpha-owner@sourceware.org] On Behalf Of Kemi Wang
> Sent: Wednesday, May 23, 2018 5:23 PM
> To: Adhemerval Zanella <adhemerval.zanella@linaro.org>; Florian Weimer <fweimer@redhat.com>; Rical Jason <rj@2c3t.io>; Carlos Donell <carlos@redhat.com>; Glibc alpha <libc-alpha@sourceware.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>; Chen, Tim C <tim.c.chen@intel.com>; Kleen, Andi <andi.kleen@intel.com>; Huang, Ying <ying.huang@intel.com>; Lu, Aaron <aaron.lu@intel.com>; Li, Aubrey <aubrey.li@intel.com>; Wang, Kemi <kemi.wang@intel.com>
> Subject: [PATCH v3 1/3] Tunables: Add tunables of spin count for pthread adaptive spin mutex
>
> 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 administrator to squeeze system performance according to different hardware capabilities and workload characteristics.
>
> The maximum value of spin count is limited to 30000 to avoid the overflow of mutex->__data.__spins variable with the possible type of short in pthread_mutex_lock ().
>
> The default value of spin count is set to 100 with the reference to the previous number of times of spinning via trylock. This value would be architecture-specific and can be tuned with kinds of benchmarks to fit most cases in future.
>
> 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 pthread_mutex_conf.c for compilation.
> * nptl/pthread_mutex_conf.h: New file.
> * nptl/pthread_mutex_conf.c: New file.
>
> ChangeLog:
> V2->V3
> a) Polish the description of glibc.mutex.spin_count tunable with the
> help from Rical Jasan.
> b) Get rid of the TUNABLE_CALLBACK_FNDECL macros in
> pthread_mutex_conf.c, as suggested by Florian Weimer.
> c) Adjust the default value of spin count to 100 with the reference of
> the previous spinning way via trylock.
>
> V1->V2
> a) Renamed nptl/mutex-conf.h -> nptl/pthread_mutex_conf.h
> b) Renamed nptl/mutex-conf.c -> nptl/pthread_mutex_conf.c
> c) Change the Makefile to compile pthread_mutex_conf.c
> d) Modify the copyright "2013-2018" -> "2018" for new added files
> e) Fix the indentation issue (tab -> double space) in
> elf/dl-tunables.list
> f) Remove the env alias LD_SPIN_COUNT in elf/dl-tunables.list
> g) Fix the typo errors and refresh glibc.mutex.spin_count tunable
> description in manual/tunables.texi.
> h) Fix the indentation issue in nptl/pthread_mutex_conf.c
> i) Fix the indentation issue for nested preprocessor (add one space for
> each level)
>
> Suggested-by: Andi Kleen <andi.kleen@intel.com>
> Signed-off-by: Kemi Wang <kemi.wang@intel.com>
> ---
> ChangeLog | 8 +++++
> elf/dl-tunables.list | 9 ++++++
> manual/tunables.texi | 22 ++++++++++++++
> nptl/Makefile | 3 +-
> nptl/pthread_mutex_conf.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++
> nptl/pthread_mutex_conf.h | 31 ++++++++++++++++++++
> 6 files changed, 146 insertions(+), 1 deletion(-) create mode 100644 nptl/pthread_mutex_conf.c create mode 100644 nptl/pthread_mutex_conf.h
>
> diff --git a/ChangeLog b/ChangeLog
> index 8032adf..c1e2a44 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,11 @@
> +2018-05-23 Kemi Wang <kemi.wang@intel.com>
> +
> + * elf/dl-tunables.list: Add glibc.mutex.spin_count entry.
> + * manual/tunables.texi: Add glibc.mutex.spin_count description.
> + * nptl/Makefile: Add pthread_mutex_conf.c for compilation.
> + * nptl/pthread_mutex_conf.h: New file.
> + * nptl/pthread_mutex_conf.c: New file.
> +
> 2018-05-23 Andreas Schwab <schwab@suse.de>
>
> [BZ #23196]
> diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list index 1f8ecb8..f1f3546 100644
> --- a/elf/dl-tunables.list
> +++ b/elf/dl-tunables.list
> @@ -121,4 +121,13 @@ glibc {
> default: 3
> }
> }
> +
> + mutex {
> + spin_count {
> + type: INT_32
> + minval: 0
> + maxval: 30000
> + default: 100
> + }
> + }
> }
> diff --git a/manual/tunables.texi b/manual/tunables.texi index be33c9f..05c5e4a 100644
> --- a/manual/tunables.texi
> +++ b/manual/tunables.texi
> @@ -281,6 +281,28 @@ 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
> +The behavior of pthread mutexes can be tuned to gain performance
> +improvements according to specific hardware capabilities and workload
> +characteristics by setting the following tunables in the @code{mutex} namespace:
> +@end deftp
> +
> +@deftp Tunable glibc.mutex.spin_count
> +The @code{glibc.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
> +PTHREAD_MUTEX_ADAPTIVE_NP GNU extension. It affects both pthread_mutex_lock and pthread_mutex_timedlock.
> +
> +The spinning is done until either the maximum spin times 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 94be92c..bd1096f 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 \
> + pthread_mutex_conf
> # pthread_setuid pthread_seteuid pthread_setreuid \
> # pthread_setresuid \
> # pthread_setgid pthread_setegid pthread_setregid \
> diff --git a/nptl/pthread_mutex_conf.c b/nptl/pthread_mutex_conf.c new file mode 100644 index 0000000..7f9eb23
> --- /dev/null
> +++ b/nptl/pthread_mutex_conf.c
> @@ -0,0 +1,74 @@
> +/* pthread_mutex_conf.c: 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/>. */
> +
> +#include "config.h"
> +#include <pthreadP.h>
> +#include <init-arch.h>
> +#include <pthread_mutex_conf.h>
> +#include <unistd.h>
> +
> +#if HAVE_TUNABLES
> +# define TUNABLE_NAMESPACE mutex
> +#endif
> +#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 = 100,
> +};
> +
> +#if HAVE_TUNABLES
> +static inline void __always_inline
> +do_set_mutex_spin_count (int32_t value) {
> + __mutex_aconf.spin_count = value;
> +}
> +
> +void
> +TUNABLE_CALLBACK (set_mutex_spin_count) (tunable_val_t *valp) {
> + int32_t value = (int32_t) (valp)->numval;
> + do_set_mutex_spin_count (value);
> +}
> +#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/pthread_mutex_conf.h b/nptl/pthread_mutex_conf.h new file mode 100644 index 0000000..e5b027c
> --- /dev/null
> +++ b/nptl/pthread_mutex_conf.h
> @@ -0,0 +1,31 @@
> +/* pthread_mutex_conf.h: 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 <pthread.h>
> +#include <time.h>
> +
> +struct mutex_config
> +{
> + int spin_count;
> +};
> +
> +extern struct mutex_config __mutex_aconf attribute_hidden;
> +
> +#endif
> --
> 2.7.4
>
3^PING
On 2018年05月30日 11:01, kemi wrote:
> Just soft PING. Anything required at my side(e.g. make this change opt-in for x86 architecture).
> Thanks for comments.
>
> https://sourceware.org/ml/libc-alpha/2018-05/msg00750.html
> https://sourceware.org/ml/libc-alpha/2018-05/msg00752.html
> https://sourceware.org/ml/libc-alpha/2018-05/msg00751.html
>
>
> On 2018年05月25日 16:51, Wang, Kemi wrote:
>> Hi, Maintainers
>> OK for master branch for this updated V3 patch series?
>> --
>> 2.7.4
>>
@@ -1,3 +1,11 @@
+2018-05-23 Kemi Wang <kemi.wang@intel.com>
+
+ * elf/dl-tunables.list: Add glibc.mutex.spin_count entry.
+ * manual/tunables.texi: Add glibc.mutex.spin_count description.
+ * nptl/Makefile: Add pthread_mutex_conf.c for compilation.
+ * nptl/pthread_mutex_conf.h: New file.
+ * nptl/pthread_mutex_conf.c: New file.
+
2018-05-23 Andreas Schwab <schwab@suse.de>
[BZ #23196]
@@ -121,4 +121,13 @@ glibc {
default: 3
}
}
+
+ mutex {
+ spin_count {
+ type: INT_32
+ minval: 0
+ maxval: 30000
+ default: 100
+ }
+ }
}
@@ -281,6 +281,28 @@ 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
+The behavior of pthread mutexes can be tuned to gain performance
+improvements according to specific hardware capabilities and workload
+characteristics by setting the following tunables in the @code{mutex} namespace:
+@end deftp
+
+@deftp Tunable glibc.mutex.spin_count
+The @code{glibc.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
+PTHREAD_MUTEX_ADAPTIVE_NP GNU extension. It affects both pthread_mutex_lock and pthread_mutex_timedlock.
+
+The spinning is done until either the maximum spin times 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
@@ -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 \
+ pthread_mutex_conf
# pthread_setuid pthread_seteuid pthread_setreuid \
# pthread_setresuid \
# pthread_setgid pthread_setegid pthread_setregid \
@@ -0,0 +1,74 @@
+/* pthread_mutex_conf.c: 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/>. */
+
+#include "config.h"
+#include <pthreadP.h>
+#include <init-arch.h>
+#include <pthread_mutex_conf.h>
+#include <unistd.h>
+
+#if HAVE_TUNABLES
+# define TUNABLE_NAMESPACE mutex
+#endif
+#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 = 100,
+};
+
+#if HAVE_TUNABLES
+static inline void __always_inline
+do_set_mutex_spin_count (int32_t value) {
+ __mutex_aconf.spin_count = value;
+}
+
+void
+TUNABLE_CALLBACK (set_mutex_spin_count) (tunable_val_t *valp) {
+ int32_t value = (int32_t) (valp)->numval;
+ do_set_mutex_spin_count (value);
+}
+#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
+};
@@ -0,0 +1,31 @@
+/* pthread_mutex_conf.h: 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 <pthread.h>
+#include <time.h>
+
+struct mutex_config
+{
+ int spin_count;
+};
+
+extern struct mutex_config __mutex_aconf attribute_hidden;
+
+#endif