* Re: [ppc] Disparity between sys_clock_getres and vdso implementation
2008-01-27 14:02 [ppc] Disparity between sys_clock_getres and vdso implementation Sripathi Kodi
@ 2008-02-04 6:08 ` Tony Breeds
2008-02-05 5:16 ` [PATCH] [POWERPC] Use a sensible default for clock_getres() in the vdso Tony Breeds
1 sibling, 0 replies; 4+ messages in thread
From: Tony Breeds @ 2008-02-04 6:08 UTC (permalink / raw)
To: Sripathi Kodi; +Cc: linuxppc-dev, paulus, linux-kernel, john stultz
On Sun, Jan 27, 2008 at 07:32:59PM +0530, Sripathi Kodi wrote:
> Hi Paul,
>
> On PPC, I see a disparity between clock_getres implementations in the
> vdso and syscall. I am using a IBM Openpower hardware and 2.6.24 kernel
> with CONFIG_HIGH_RES_TIMERS=y.
>
> clock_getres call for CLOCK_REALTIME returns 1 millisecond. However,
> when I edit arch/powerpc/kernel/vdso*/gettimeofday.S to force it to use
> sys_clock_getres, I get 1 nanosecond resolution. The code in vdso seems
> to be returning some pre-defined (incorrect) variables.
>
> Could you please let me know the reason for this? Is it something that
> should be fixed in vdso?
Almost certainly It's something I missed when I enabled highres timers
on powerpc.
I'll fix this tomorrow.
Yours Tony
linux.conf.au http://linux.conf.au/ || http://lca2008.linux.org.au/
Jan 28 - Feb 02 2008 The Australian Linux Technical Conference!
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] [POWERPC] Use a sensible default for clock_getres() in the vdso.
2008-01-27 14:02 [ppc] Disparity between sys_clock_getres and vdso implementation Sripathi Kodi
2008-02-04 6:08 ` Tony Breeds
@ 2008-02-05 5:16 ` Tony Breeds
2008-02-05 9:07 ` Chirag Jog
1 sibling, 1 reply; 4+ messages in thread
From: Tony Breeds @ 2008-02-05 5:16 UTC (permalink / raw)
To: Sripathi Kodi; +Cc: linuxppc-dev, paulus, linux-kernel, john stultz
On Sun, Jan 27, 2008 at 07:32:59PM +0530, Sripathi Kodi wrote:
> Hi Paul,
>
> On PPC, I see a disparity between clock_getres implementations in the
> vdso and syscall. I am using a IBM Openpower hardware and 2.6.24 kernel
> with CONFIG_HIGH_RES_TIMERS=y.
>
> clock_getres call for CLOCK_REALTIME returns 1 millisecond. However,
> when I edit arch/powerpc/kernel/vdso*/gettimeofday.S to force it to use
> sys_clock_getres, I get 1 nanosecond resolution. The code in vdso seems
> to be returning some pre-defined (incorrect) variables.
>
> Could you please let me know the reason for this? Is it something that
> should be fixed in vdso?
Can you try the attached patch and see it if works for you?
From: Tony Breeds <tony@bakeyournoodle.com>
Subject: [PATCH] [POWERPC] Use a sensible default for clock_getres() in the vdso.
This ensures that the syscall and the (fast) vdso versions of clock_getres()
will return the same resolution.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
---
arch/powerpc/kernel/asm-offsets.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index ed083fe..e6e4928 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -22,6 +22,7 @@
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/suspend.h>
+#include <linux/hrtimer.h>
#ifdef CONFIG_PPC64
#include <linux/time.h>
#include <linux/hardirq.h>
@@ -312,7 +313,7 @@ int main(void)
DEFINE(CLOCK_REALTIME, CLOCK_REALTIME);
DEFINE(CLOCK_MONOTONIC, CLOCK_MONOTONIC);
DEFINE(NSEC_PER_SEC, NSEC_PER_SEC);
- DEFINE(CLOCK_REALTIME_RES, TICK_NSEC);
+ DEFINE(CLOCK_REALTIME_RES, (KTIME_MONOTONIC_RES).tv64);
#ifdef CONFIG_BUG
DEFINE(BUG_ENTRY_SIZE, sizeof(struct bug_entry));
--
1.5.4
Yours Tony
linux.conf.au http://linux.conf.au/ || http://lca2008.linux.org.au/
Jan 28 - Feb 02 2008 The Australian Linux Technical Conference!
^ permalink raw reply related [flat|nested] 4+ messages in thread