[v2,2/6] linux: Assume clock_getres CLOCK_{PROCESS,THREAD}_CPUTIME_ID
Commit Message
Changes from previous version:
- Remove ia64 itc drift check and assume kernel handles it correctly.
---
This patch assumes that clock_getres syscall always support
CLOCK_PROCESS_CPUTIME_ID and CLOCK_THREAD_CPUTIME_ID, so there is no need
to fallback to hp-timing support for _SC_MONOTONIC_CLOCK. This allows
simplify the sysconf support to always use the syscall.
The ia64 implementation is also simplified and consolidate in one file.
Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu.
* sysdeps/unix/sysv/linux/ia64/has_cpuclock.c: Remove file.
* sysdeps/unix/sysv/linux/ia64/sysconf.c: Likewise.
* sysdeps/unix/sysv/linux/sysconf.c (has_cpuclock): Remove function.
(check_clock_getres): New function.
(__sysconf): Use check_clock_getres instead of has_cpuclock.
---
sysdeps/unix/sysv/linux/ia64/has_cpuclock.c | 51 ---------------------
sysdeps/unix/sysv/linux/ia64/sysconf.c | 30 ------------
sysdeps/unix/sysv/linux/sysconf.c | 48 ++++++-------------
3 files changed, 13 insertions(+), 116 deletions(-)
delete mode 100644 sysdeps/unix/sysv/linux/ia64/has_cpuclock.c
delete mode 100644 sysdeps/unix/sysv/linux/ia64/sysconf.c
Comments
Ping.
On 18/02/2019 18:11, Adhemerval Zanella wrote:
> Changes from previous version:
>
> - Remove ia64 itc drift check and assume kernel handles it correctly.
>
> ---
>
> This patch assumes that clock_getres syscall always support
> CLOCK_PROCESS_CPUTIME_ID and CLOCK_THREAD_CPUTIME_ID, so there is no need
> to fallback to hp-timing support for _SC_MONOTONIC_CLOCK. This allows
> simplify the sysconf support to always use the syscall.
>
> The ia64 implementation is also simplified and consolidate in one file.
>
> Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu.
>
> * sysdeps/unix/sysv/linux/ia64/has_cpuclock.c: Remove file.
> * sysdeps/unix/sysv/linux/ia64/sysconf.c: Likewise.
> * sysdeps/unix/sysv/linux/sysconf.c (has_cpuclock): Remove function.
> (check_clock_getres): New function.
> (__sysconf): Use check_clock_getres instead of has_cpuclock.
> ---
> sysdeps/unix/sysv/linux/ia64/has_cpuclock.c | 51 ---------------------
> sysdeps/unix/sysv/linux/ia64/sysconf.c | 30 ------------
> sysdeps/unix/sysv/linux/sysconf.c | 48 ++++++-------------
> 3 files changed, 13 insertions(+), 116 deletions(-)
> delete mode 100644 sysdeps/unix/sysv/linux/ia64/has_cpuclock.c
> delete mode 100644 sysdeps/unix/sysv/linux/ia64/sysconf.c
>
> diff --git a/sysdeps/unix/sysv/linux/ia64/has_cpuclock.c b/sysdeps/unix/sysv/linux/ia64/has_cpuclock.c
> deleted file mode 100644
> index b3afb37f8b..0000000000
> --- a/sysdeps/unix/sysv/linux/ia64/has_cpuclock.c
> +++ /dev/null
> @@ -1,51 +0,0 @@
> -/* Copyright (C) 2000-2019 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 <errno.h>
> -#include <fcntl.h>
> -#include <unistd.h>
> -#include <sys/stat.h>
> -#include <sys/types.h>
> -#include <not-cancel.h>
> -
> -static int itc_usable;
> -
> -static int
> -has_cpuclock (void)
> -{
> - if (__builtin_expect (itc_usable == 0, 0))
> - {
> - int newval = 1;
> - int fd = __open_nocancel ("/proc/sal/itc_drift", O_RDONLY);
> - if (__builtin_expect (fd != -1, 1))
> - {
> - char buf[16];
> - /* We expect the file to contain a single digit followed by
> - a newline. If the format changes we better not rely on
> - the file content. */
> - if (__read_nocancel (fd, buf, sizeof buf) != 2
> - || buf[0] != '0' || buf[1] != '\n')
> - newval = -1;
> -
> - __close_nocancel_nostatus (fd);
> - }
> -
> - itc_usable = newval;
> - }
> -
> - return itc_usable;
> -}
> diff --git a/sysdeps/unix/sysv/linux/ia64/sysconf.c b/sysdeps/unix/sysv/linux/ia64/sysconf.c
> deleted file mode 100644
> index ef75322f1f..0000000000
> --- a/sysdeps/unix/sysv/linux/ia64/sysconf.c
> +++ /dev/null
> @@ -1,30 +0,0 @@
> -/* Get file-specific information about a file. Linux/ia64 version.
> - Copyright (C) 2003-2019 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 <assert.h>
> -#include <stdbool.h>
> -#include <stdlib.h>
> -#include <unistd.h>
> -
> -
> -#include "has_cpuclock.c"
> -#define HAS_CPUCLOCK(name) (has_cpuclock () ? _POSIX_VERSION : -1)
> -
> -
> -/* Now the generic Linux version. */
> -#include <sysdeps/unix/sysv/linux/sysconf.c>
> diff --git a/sysdeps/unix/sysv/linux/sysconf.c b/sysdeps/unix/sysv/linux/sysconf.c
> index 4b297ba35f..2027444488 100644
> --- a/sysdeps/unix/sysv/linux/sysconf.c
> +++ b/sysdeps/unix/sysv/linux/sysconf.c
> @@ -35,33 +35,18 @@
> static long int posix_sysconf (int name);
>
>
> -#ifndef HAS_CPUCLOCK
> static long int
> -has_cpuclock (int name)
> +check_clock_getres (clockid_t clk_id)
> {
> -# if defined __NR_clock_getres || HP_TIMING_AVAIL
> - /* If we have HP_TIMING, we will fall back on that if the system
> - call does not work, so we support it either way. */
> -# if !HP_TIMING_AVAIL
> - /* Check using the clock_getres system call. */
> struct timespec ts;
> INTERNAL_SYSCALL_DECL (err);
> - int r = INTERNAL_SYSCALL (clock_getres, err, 2,
> - (name == _SC_CPUTIME
> - ? CLOCK_PROCESS_CPUTIME_ID
> - : CLOCK_THREAD_CPUTIME_ID),
> - &ts);
> + /* Avoid setting errno to we can check whether the kernel supports
> + the CLK_ID. */
> + int r = INTERNAL_SYSCALL_CALL (clock_getres, err, clk_id, &ts);
> if (INTERNAL_SYSCALL_ERROR_P (r, err))
> return -1;
> -# endif
> return _POSIX_VERSION;
> -# else
> - return -1;
> -# endif
> }
> -# define HAS_CPUCLOCK(name) has_cpuclock (name)
> -#endif
> -
>
> /* Get the value of the system variable NAME. */
> long int
> @@ -71,29 +56,21 @@ __sysconf (int name)
>
> switch (name)
> {
> - struct rlimit rlimit;
> -#ifdef __NR_clock_getres
> case _SC_MONOTONIC_CLOCK:
> - /* Check using the clock_getres system call. */
> - {
> - struct timespec ts;
> - INTERNAL_SYSCALL_DECL (err);
> - int r;
> - r = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
> - return INTERNAL_SYSCALL_ERROR_P (r, err) ? -1 : _POSIX_VERSION;
> - }
> -#endif
> -
> + return check_clock_getres (CLOCK_MONOTONIC);
> case _SC_CPUTIME:
> + return check_clock_getres (CLOCK_PROCESS_CPUTIME_ID);
> case _SC_THREAD_CPUTIME:
> - return HAS_CPUCLOCK (name);
> + return check_clock_getres (CLOCK_THREAD_CPUTIME_ID);
>
> - case _SC_ARG_MAX:
> + case _SC_ARG_MAX: {
> + struct rlimit rlimit;
> /* Use getrlimit to get the stack limit. */
> if (__getrlimit (RLIMIT_STACK, &rlimit) == 0)
> return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4);
>
> return legacy_ARG_MAX;
> + } break;
>
> case _SC_NGROUPS_MAX:
> /* Try to read the information from the /proc/sys/kernel/ngroups_max
> @@ -101,13 +78,14 @@ __sysconf (int name)
> procfname = "/proc/sys/kernel/ngroups_max";
> break;
>
> - case _SC_SIGQUEUE_MAX:
> + case _SC_SIGQUEUE_MAX: {
> + struct rlimit rlimit;
> if (__getrlimit (RLIMIT_SIGPENDING, &rlimit) == 0)
> return rlimit.rlim_cur;
>
> /* The /proc/sys/kernel/rtsig-max file contains the answer. */
> procfname = "/proc/sys/kernel/rtsig-max";
> - break;
> + } break;
>
> default:
> break;
>
On Feb 18 2019, Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
> This patch assumes that clock_getres syscall always support
> CLOCK_PROCESS_CPUTIME_ID and CLOCK_THREAD_CPUTIME_ID, so there is no need
> to fallback to hp-timing support for _SC_MONOTONIC_CLOCK. This allows
> simplify the sysconf support to always use the syscall.
Under which condition can clock_getres return an error for these clocks?
> diff --git a/sysdeps/unix/sysv/linux/sysconf.c b/sysdeps/unix/sysv/linux/sysconf.c
> index 4b297ba35f..2027444488 100644
> --- a/sysdeps/unix/sysv/linux/sysconf.c
> +++ b/sysdeps/unix/sysv/linux/sysconf.c
> @@ -35,33 +35,18 @@
> static long int posix_sysconf (int name);
>
>
> -#ifndef HAS_CPUCLOCK
> static long int
> -has_cpuclock (int name)
> +check_clock_getres (clockid_t clk_id)
> {
> -# if defined __NR_clock_getres || HP_TIMING_AVAIL
> - /* If we have HP_TIMING, we will fall back on that if the system
> - call does not work, so we support it either way. */
> -# if !HP_TIMING_AVAIL
> - /* Check using the clock_getres system call. */
> struct timespec ts;
> INTERNAL_SYSCALL_DECL (err);
> - int r = INTERNAL_SYSCALL (clock_getres, err, 2,
> - (name == _SC_CPUTIME
> - ? CLOCK_PROCESS_CPUTIME_ID
> - : CLOCK_THREAD_CPUTIME_ID),
> - &ts);
> + /* Avoid setting errno to we can check whether the kernel supports
s/to/so/
> + the CLK_ID. */
> + int r = INTERNAL_SYSCALL_CALL (clock_getres, err, clk_id, &ts);
> if (INTERNAL_SYSCALL_ERROR_P (r, err))
> return -1;
> -# endif
> return _POSIX_VERSION;
> -# else
> - return -1;
> -# endif
> }
> -# define HAS_CPUCLOCK(name) has_cpuclock (name)
> -#endif
> -
>
> /* Get the value of the system variable NAME. */
> long int
> @@ -71,29 +56,21 @@ __sysconf (int name)
>
> switch (name)
> {
> - struct rlimit rlimit;
> -#ifdef __NR_clock_getres
> case _SC_MONOTONIC_CLOCK:
> - /* Check using the clock_getres system call. */
> - {
> - struct timespec ts;
> - INTERNAL_SYSCALL_DECL (err);
> - int r;
> - r = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
> - return INTERNAL_SYSCALL_ERROR_P (r, err) ? -1 : _POSIX_VERSION;
> - }
> -#endif
> -
> + return check_clock_getres (CLOCK_MONOTONIC);
> case _SC_CPUTIME:
> + return check_clock_getres (CLOCK_PROCESS_CPUTIME_ID);
> case _SC_THREAD_CPUTIME:
> - return HAS_CPUCLOCK (name);
> + return check_clock_getres (CLOCK_THREAD_CPUTIME_ID);
>
> - case _SC_ARG_MAX:
> + case _SC_ARG_MAX: {
Brace on next line.
> + struct rlimit rlimit;
> /* Use getrlimit to get the stack limit. */
> if (__getrlimit (RLIMIT_STACK, &rlimit) == 0)
> return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4);
>
> return legacy_ARG_MAX;
> + } break;
No break needed.
>
> case _SC_NGROUPS_MAX:
> /* Try to read the information from the /proc/sys/kernel/ngroups_max
> @@ -101,13 +78,14 @@ __sysconf (int name)
> procfname = "/proc/sys/kernel/ngroups_max";
> break;
>
> - case _SC_SIGQUEUE_MAX:
> + case _SC_SIGQUEUE_MAX: {
Brace on next line.
> + struct rlimit rlimit;
> if (__getrlimit (RLIMIT_SIGPENDING, &rlimit) == 0)
> return rlimit.rlim_cur;
>
> /* The /proc/sys/kernel/rtsig-max file contains the answer. */
> procfname = "/proc/sys/kernel/rtsig-max";
> - break;
> + } break;
Line break after brace.
Andreas.
deleted file mode 100644
@@ -1,51 +0,0 @@
-/* Copyright (C) 2000-2019 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 <errno.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <not-cancel.h>
-
-static int itc_usable;
-
-static int
-has_cpuclock (void)
-{
- if (__builtin_expect (itc_usable == 0, 0))
- {
- int newval = 1;
- int fd = __open_nocancel ("/proc/sal/itc_drift", O_RDONLY);
- if (__builtin_expect (fd != -1, 1))
- {
- char buf[16];
- /* We expect the file to contain a single digit followed by
- a newline. If the format changes we better not rely on
- the file content. */
- if (__read_nocancel (fd, buf, sizeof buf) != 2
- || buf[0] != '0' || buf[1] != '\n')
- newval = -1;
-
- __close_nocancel_nostatus (fd);
- }
-
- itc_usable = newval;
- }
-
- return itc_usable;
-}
deleted file mode 100644
@@ -1,30 +0,0 @@
-/* Get file-specific information about a file. Linux/ia64 version.
- Copyright (C) 2003-2019 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 <assert.h>
-#include <stdbool.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-
-#include "has_cpuclock.c"
-#define HAS_CPUCLOCK(name) (has_cpuclock () ? _POSIX_VERSION : -1)
-
-
-/* Now the generic Linux version. */
-#include <sysdeps/unix/sysv/linux/sysconf.c>
@@ -35,33 +35,18 @@
static long int posix_sysconf (int name);
-#ifndef HAS_CPUCLOCK
static long int
-has_cpuclock (int name)
+check_clock_getres (clockid_t clk_id)
{
-# if defined __NR_clock_getres || HP_TIMING_AVAIL
- /* If we have HP_TIMING, we will fall back on that if the system
- call does not work, so we support it either way. */
-# if !HP_TIMING_AVAIL
- /* Check using the clock_getres system call. */
struct timespec ts;
INTERNAL_SYSCALL_DECL (err);
- int r = INTERNAL_SYSCALL (clock_getres, err, 2,
- (name == _SC_CPUTIME
- ? CLOCK_PROCESS_CPUTIME_ID
- : CLOCK_THREAD_CPUTIME_ID),
- &ts);
+ /* Avoid setting errno to we can check whether the kernel supports
+ the CLK_ID. */
+ int r = INTERNAL_SYSCALL_CALL (clock_getres, err, clk_id, &ts);
if (INTERNAL_SYSCALL_ERROR_P (r, err))
return -1;
-# endif
return _POSIX_VERSION;
-# else
- return -1;
-# endif
}
-# define HAS_CPUCLOCK(name) has_cpuclock (name)
-#endif
-
/* Get the value of the system variable NAME. */
long int
@@ -71,29 +56,21 @@ __sysconf (int name)
switch (name)
{
- struct rlimit rlimit;
-#ifdef __NR_clock_getres
case _SC_MONOTONIC_CLOCK:
- /* Check using the clock_getres system call. */
- {
- struct timespec ts;
- INTERNAL_SYSCALL_DECL (err);
- int r;
- r = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
- return INTERNAL_SYSCALL_ERROR_P (r, err) ? -1 : _POSIX_VERSION;
- }
-#endif
-
+ return check_clock_getres (CLOCK_MONOTONIC);
case _SC_CPUTIME:
+ return check_clock_getres (CLOCK_PROCESS_CPUTIME_ID);
case _SC_THREAD_CPUTIME:
- return HAS_CPUCLOCK (name);
+ return check_clock_getres (CLOCK_THREAD_CPUTIME_ID);
- case _SC_ARG_MAX:
+ case _SC_ARG_MAX: {
+ struct rlimit rlimit;
/* Use getrlimit to get the stack limit. */
if (__getrlimit (RLIMIT_STACK, &rlimit) == 0)
return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4);
return legacy_ARG_MAX;
+ } break;
case _SC_NGROUPS_MAX:
/* Try to read the information from the /proc/sys/kernel/ngroups_max
@@ -101,13 +78,14 @@ __sysconf (int name)
procfname = "/proc/sys/kernel/ngroups_max";
break;
- case _SC_SIGQUEUE_MAX:
+ case _SC_SIGQUEUE_MAX: {
+ struct rlimit rlimit;
if (__getrlimit (RLIMIT_SIGPENDING, &rlimit) == 0)
return rlimit.rlim_cur;
/* The /proc/sys/kernel/rtsig-max file contains the answer. */
procfname = "/proc/sys/kernel/rtsig-max";
- break;
+ } break;
default:
break;