diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/getsysstats.c | 32 |
2 files changed, 36 insertions, 1 deletions
@@ -1,3 +1,8 @@ +2011-06-22 Ulrich Drepper <drepper@gmail.com> + + * sysdeps/unix/sysv/linux/getsysstats.c (__get_nprocs): Rate limit + reading the information from the /proc filesystem to once a second. + 2011-06-21 Andreas Jaeger <aj@suse.de> * sysdeps/unix/sysv/linux/bits/sigcontext.h: Fix definition of diff --git a/sysdeps/unix/sysv/linux/getsysstats.c b/sysdeps/unix/sysv/linux/getsysstats.c index af454b650d..a13b6e3e37 100644 --- a/sysdeps/unix/sysv/linux/getsysstats.c +++ b/sysdeps/unix/sysv/linux/getsysstats.c @@ -1,5 +1,5 @@ /* Determine various system internal values, Linux version. - Copyright (C) 1996-2003,2006,2007,2009,2010 Free Software Foundation, Inc. + Copyright (C) 1996-2003,2006,2007,2009,2010,2011 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. @@ -35,6 +35,16 @@ #include <atomic.h> #include <not-cancel.h> +#include <kernel-features.h> + +#ifndef HAVE_CLOCK_GETTIME_VSYSCALL +# undef INTERNAL_VSYSCALL +# define INTERNAL_VSYSCALL INTERNAL_SYSCALL +# undef INLINE_VSYSCALL +# define INLINE_VSYSCALL INLINE_SYSCALL +#else +# include <bits/libc-vdso.h> +#endif /* How we can determine the number of available processors depends on @@ -128,6 +138,22 @@ next_line (int fd, char *const buffer, char **cp, char **re, int __get_nprocs () { + static int cached_result; + static time_t timestamp; + +#ifdef __ASSUME_POSIX_TIMERS + struct timespec ts; + INTERNAL_SYSCALL_DECL (err); + INTERNAL_VSYSCALL (clock_gettime, err, 2, CLOCK_REALTIME, &ts); +#else + struct timeval ts; + gettimeofday (&ts, NULL); +#endif + time_t prev = timestamp; + atomic_read_barrier (); + if (ts.tv_sec == prev) + return cached_result; + /* XXX Here will come a test for the new system call. */ const size_t buffer_size = __libc_use_alloca (8192) ? 8192 : 512; @@ -169,6 +195,10 @@ __get_nprocs () } } + cached_result = result; + atomic_write_barrier (); + timestamp = ts.tv_sec; + return result; } weak_alias (__get_nprocs, get_nprocs) |