+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
/* 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.
#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
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;
}
}
+ cached_result = result;
+ atomic_write_barrier ();
+ timestamp = ts.tv_sec;
+
return result;
}
weak_alias (__get_nprocs, get_nprocs)