Re: [PATCH V2] tipc: Use bsearch library function

[Joe Perches]

On Sat, 2017-09-16 at 17:36 +0800, Ying Xue wrote:
> On 09/16/2017 05:26 PM, Joe Perches wrote:
> > On Sat, 2017-09-16 at 17:02 +0800, Ying Xue wrote:
> > > On 09/16/2017 03:50 PM, Thomas Meyer wrote:
> > > > Use common library function rather than explicitly coding
> > > > some variant of it yourself.
> > > > 
> > > > Signed-off-by: Thomas Meyer <thomas@xxxxxxxx>
> > > 
> > > Acked-by: Ying Xue <ying.xue@xxxxxxxxxxxxx>
> > 
> > Are you sure you want to do this?
> > 
> > Note the comment above nameseq_find_subseq
> > 
> >  * Very time-critical, so binary searches through sub-sequence array.
> > 
> > What impact does this change have on performance?
> 
> Sorry, I couldn't see any essential difference between this new
> implementation and the original one except that the former tries to use
> the library function - bsearch() to replace the original binary search
> algorithm implemented in TIPC itself. Therefore, I don't think the
> change will have a big impact on performance.
> 
> If I miss something, please let me know.

Comparison via a function pointer in bsearch is slower
than direct code without the function call overhead.