diff options
| author | Adhemerval Zanella <azanella@linux.vnet.ibm.com> | 2013-04-22 09:29:33 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2013-04-23 16:05:05 +1000 |
| commit | fcb41a2030abe0eb716ef0798035ef9562097f42 (patch) | |
| tree | 4b063cc1cb872fb9609fd90485c7b602b9fdc57f /arch/powerpc/kernel/vdso.c | |
| parent | af81d7878c641629f2693ae3fdaf74b4af14dfca (diff) | |
powerpc: Add VDSO version of time
On 04/18/2013 07:38 PM, Anton Blanchard wrote:
> Since you are only reading one long you shouldn't need to check the
> update count and loop, you will always see a consistent value. The
> system call version of time() just does an unprotected load for example.
Fixed.
> With the above change and with Michael's comments covered (decent
> changelog entry and Signed-off-by):
>
> Acked-by: Anton Blanchard <anton@samba.org>
Thanks for the review, below the updated patch:
From: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
This patch implement the time syscall as vDSO. The performance speedups
are:
Baseline PPC32: 380 nsec
Baseline PPC64: 350 nsec
vdso PPC32: 20 nsec
vsdo PPC64: 20 nsec
Tested on 64 bit build with both 32 bit and 64 bit userland.
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/vdso.c')
| -rw-r--r-- | arch/powerpc/kernel/vdso.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index 1b2076f049c..d4f463ac65b 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -113,6 +113,10 @@ static struct vdso_patch_def vdso_patches[] = { CPU_FTR_USE_TB, 0, "__kernel_get_tbfreq", NULL }, + { + CPU_FTR_USE_TB, 0, + "__kernel_time", NULL + }, }; /* |