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PowerPC: gettimeofday optimization by using IFUNC
- From: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- To: "GNU C. Library" <libc-alpha at sourceware dot org>
- Date: Fri, 22 Feb 2013 16:31:01 -0300
- Subject: PowerPC: gettimeofday optimization by using IFUNC
Hi,
This patch make gettimeofday uses IFUNC and optimizing its call by avoid
the unnecessary way through glibc's internal __gettimeofday. Any tips,
advices, comments?
2013-02-22 Adhemerval Zanella <azanella@linux.vnet.ibm.com>
* sysdeps/unix/sysv/linux/powerpc/gettimeofday.c: Optimizing gettimeofday
by using IFUNC.
(gettimeofday_ifunc): Add IFUNC.
(__gettimeofday_syscall): Sycall fallback when vDSO is not present.
(__gettimeofday): Using SYSCALL directly in static mode.
--
diff --git a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
index f607485..ee760b7 100644
--- a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
@@ -15,25 +15,49 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-#include <sysdep.h>
-#include <stddef.h>
+
#include <sys/time.h>
-#include <time.h>
-#include <hp-timing.h>
-#include <bits/libc-vdso.h>
+#ifdef SHARED
+
+# include <dl-vdso.h>
+# include <bits/libc-vdso.h>
+
+void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
+
+static int
+__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
+{
+ return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+}
+
+void *
+gettimeofday_ifunc (void)
+{
+ /* If the vDSO is not available we fall back syscall. */
+ return (__vdso_gettimeofday ? &__vdso_gettimeofday
+ : __gettimeofday_syscall);
+}
+asm (".type __gettimeofday, %gnu_indirect_function");
+
+/* This is doing "libc_hidden_def (__gettimeofday)" but the compiler won't
+ let us do it in C because it doesn't know we're defining __gettimeofday
+ here in this file. */
+asm (".globl __GI___gettimeofday\n"
+ "__GI___gettimeofday = __gettimeofday");
+
+#else
-/* Get the current time of day and timezone information,
- putting it into *TV and *TZ. If TZ is NULL, *TZ is not filled.
- Returns 0 on success, -1 on errors. */
+# include <sysdep.h>
+# include <errno.h>
int
-__gettimeofday (tv, tz)
- struct timeval *tv;
- struct timezone *tz;
+__gettimeofday (struct timeval *tv, struct timezone *tz)
{
- return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
+ return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
}
libc_hidden_def (__gettimeofday)
+
+#endif
weak_alias (__gettimeofday, gettimeofday)
libc_hidden_weak (gettimeofday)
--
1.7.1