lib/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2025-07-30 22:43:12 +03:00
Code Activity

nptl: Eliminate <smp.h> and __is_smp

Browse Source 
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  <adhemerval.zanella@linaro.org>
This commit is contained in:
Florian Weimer
2020-11-13 15:19:41 +01:00
parent d5c4cce9c3
commit 26f7c72a99
9 changed files with 20 additions and 121 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
sysdeps/unix/sysv/linux/i386/smp.h
View File

@ -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 <https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/utsname.h>
#include <not-cancel.h>
/* 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;
}

20
sysdeps/unix/sysv/linux/sh/adaptive_spin_count.h Normal file
View File

@ -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
<https://www.gnu.org/licenses/>. */
/* Disable spinning because sh is always uniprocessor. */
#define DEFAULT_ADAPTIVE_COUNT 0

23
sysdeps/unix/sysv/linux/sh/smp.h
View File

@ -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 <https://www.gnu.org/licenses/>. */
static inline int
is_smp_system (void)
{
return 0;
}