Messages in this thread | | | Subject | Re: [PATCH v2 4/8] powerpc/vdso32: inline __get_datapage() | From | Christophe Leroy <> | Date | Fri, 13 Sep 2019 12:59:31 +0200 |
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Hi Santosh,
Le 26/08/2019 à 07:44, Santosh Sivaraj a écrit : > Hi Christophe, > > Christophe Leroy <christophe.leroy@c-s.fr> writes: > >> __get_datapage() is only a few instructions to retrieve the >> address of the page where the kernel stores data to the VDSO. >> >> By inlining this function into its users, a bl/blr pair and >> a mflr/mtlr pair is avoided, plus a few reg moves. >> >> The improvement is noticeable (about 55 nsec/call on an 8xx) >> >> vdsotest before the patch: >> gettimeofday: vdso: 731 nsec/call >> clock-gettime-realtime-coarse: vdso: 668 nsec/call >> clock-gettime-monotonic-coarse: vdso: 745 nsec/call >> >> vdsotest after the patch: >> gettimeofday: vdso: 677 nsec/call >> clock-gettime-realtime-coarse: vdso: 613 nsec/call >> clock-gettime-monotonic-coarse: vdso: 690 nsec/call >> >> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> >> --- >> arch/powerpc/kernel/vdso32/cacheflush.S | 10 +++++----- >> arch/powerpc/kernel/vdso32/datapage.S | 29 ++++------------------------- >> arch/powerpc/kernel/vdso32/datapage.h | 11 +++++++++++ >> arch/powerpc/kernel/vdso32/gettimeofday.S | 13 ++++++------- >> 4 files changed, 26 insertions(+), 37 deletions(-) >> create mode 100644 arch/powerpc/kernel/vdso32/datapage.h > > The datapage.h file should ideally be moved under include/asm, then we can use > the same for powerpc64 too.
I have a more ambitious project indeed.
Most of the VDSO code is duplicated between vdso32 and vdso64. I'm aiming at merging everything into a single source code.
This means we would have to generate vdso32.so and vdso64.so out of the same source files. Any idea on how to do that ? I'm not too good at creating Makefiles. I guess we would have everything in arch/powerpc/kernel/vdso/ and would have to build the objects twice, once in arch/powerpc/kernel/vdso32/ and once in arch/powerpc/kernel/vdso64/
Christophe
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