Subj : Re: Performance impact of disaligned structures
To   : comp.programming
From : Scott Moore
Date : Tue Oct 04 2005 12:37 pm

Gioele Barabucci wrote On 10/04/05 06:48,:
> How much "worse" is this structure
> 
> struct {
>   uint64 length;
>   uint32 id;
>   uint64 *next;     /* this is 32 bits aligned */
>   uint64 data[256]; /* this starts on the 32 bits boundary */
> }
> 
> compared to this other
> 
> struct {
>   uint64 length;
>   uint32 id;
>   uint32 padding;
>   uint64 *next;     /* now this is 64 bits aligned */
>   uint64 data[256]; /* and this starts on the 64 bits boundary */
> }
> 
> on 32 bits and 64 bits architectures?
> 

Probally no different, since the compiler likely padded the structure
for proper alignment for you, unless you used flags to disable that.

.