linux/arch/powerpc/kernel/vdso32
Adhemerval Zanella fcb41a2030 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>
2013-04-23 16:05:05 +10:00
..
.gitignore
cacheflush.S
datapage.S
getcpu.S
gettimeofday.S powerpc: Add VDSO version of time 2013-04-23 16:05:05 +10:00
Makefile
note.S
sigtramp.S
vdso32_wrapper.S
vdso32.lds.S powerpc: Add VDSO version of time 2013-04-23 16:05:05 +10:00