Re: [Boost-users] Does shared_array's get() methodintroduceruntimeoverhead?

From: Peng Yu (pengyu.ut_at_[hidden])
Date: 2006-10-24 21:31:05

On 10/24/06, Sohail Somani <s.somani_at_[hidden]> wrote:
> > -----Original Message-----
> > From: boost-users-bounces_at_[hidden]
> > [mailto:boost-users-bounces_at_[hidden]] On Behalf Of Peng Yu
> > Sent: Tuesday, October 24, 2006 5:33 PM
> > Does it mean that code segment 1 is as fast as segment 2, but code
> > segment 3 is the slowest?
> >
> > ///////1
> > boost::shared_array a(new int[100]);
> > for(int i = 0; i < 100; ++ i)
> >  a.get()[i] = i;
> >
> > ////////2
> > boost::shared_array a(new int[100]);
> > int a_ptr = a.get();
> > for(int i = 0; i < 100; ++ i)
> >  a_ptr[i] = i;
> >
> > ////////3
> > boost::shared_array a(new int[100]);
> > for(int i = 0; i < 100; ++ i)
> >  a[i] = i;
>
> All I can say is profile, profile, profile!
>
> PS: Profile.
> PPS: I'd guesstimate with a proper C++ compiler + optimizer, you
> wouldn't notice much of a difference between 1 and 3.

Could you recommend a profiler on linux x86?

Thanks,
Peng