[Boost-users] [Boost.Array] surprising performance issue

From: Bryan Green (bgreen_at_[hidden])
Date: 2007-11-26 18:44:54

Hello,
I've discovered a situation where using boost::array results in a
2-fold performance degradation over other array types, including C arrays,
tr1::array, and a simple handwritten array class.
While the tr1::array performs well, I was suprised to find that it pads the
array, so sizeof(tr1::array<3,float>) == sizeof(tr1::array<4,float>).  Is
that a requirement of tr1::array?

Anyway, the performance problem can be seen using Intel C++ (v9.1) on the
Itanium platform, using '-O3' optimization.

I'm forced to take boost::array out of my computation's inner loop.
Is this a previously known issue?  Any ideas why this performance
discrepancy might exist?

Thanks,
Bryan Green