Messages in this thread Patch in this message | | | Subject | Re: [PATCH] ktime: Simplify ktime_* comparison functions | From | Joe Perches <> | Date | Fri, 26 May 2017 03:20:20 -0700 |
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On Fri, 2017-05-26 at 12:09 +0200, Mariusz Skamra wrote: > This simplifies ktime_compare, ktime_after and ktime_before to be defines. > ktime_compare verified on x86_64 machine, gives a code 4 asm instruction > less compared to the previous solution. Time measured is up to 2 times less. > Signed-off-by: Mariusz Skamra <mariuszx.skamra@intel.com> > Acked-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@intel.com> > --- > include/linux/ktime.h | 19 +++---------------- > 1 file changed, 3 insertions(+), 16 deletions(-) > > diff --git a/include/linux/ktime.h b/include/linux/ktime.h > index 0c8bd45..3f3dfcd 100644 > --- a/include/linux/ktime.h > +++ b/include/linux/ktime.h > @@ -106,14 +106,7 @@ static inline ktime_t timeval_to_ktime(struct timeval tv) > * cmp1 == cmp2: return 0 > * cmp1 > cmp2: return >0 > */ > -static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2) > -{ > - if (cmp1 < cmp2) > - return -1; > - if (cmp1 > cmp2) > - return 1; > - return 0; > -} > +#define ktime_compare(cmp1, cmp2) ktime_sub(cmp1, cmp2)
Why not just change ktime_compare to
static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2) { return ktime_sub(cmp1, cmp2); }
> > /** > * ktime_after - Compare if a ktime_t value is bigger than another one. > @@ -122,10 +115,7 @@ static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2) > * > * Return: true if cmp1 happened after cmp2. > */ > -static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2) > -{ > - return ktime_compare(cmp1, cmp2) > 0; > -} > +#define ktime_after(cmp1, cmp2) (ktime_compare(cmp1, cmp2) > 0)
The ktime_after and ktime_before changes shouldn't matter in generated objects.
I suggest these conversions from static inline to #define are not changes for the better. > /** > * ktime_before - Compare if a ktime_t value is smaller than another one. > @@ -134,10 +124,7 @@ static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2) > * > * Return: true if cmp1 happened before cmp2. > */ > -static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2) > -{ > - return ktime_compare(cmp1, cmp2) < 0; > -} > +#define ktime_before(cmp1, cmp2) (ktime_compare(cmp1, cmp2) < 0) > > #if BITS_PER_LONG < 64 > extern s64 __ktime_divns(const ktime_t kt, s64 div);
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