On Sat, Aug 6, 2011 at 23:59, subin gangadharan
[off-list ref] wrote:

Hi All,
I have some doubts on the alignment requirement.It would be really
helpful,if someone can shed some light on this.
Why there are so many different types of alignment like 4 byte, 8 byte,16
byte ?.My exact question is, in a 32 bit machine(I assume processor reads
data in 4 bytes),how 16 byte alignment makes different from 4 byte alignment
?.How this will influence the processor performance ?.

personal guess: cache line alignment?

... so the data all can be read in one read swipe.....

or in other hand, if several data has different access type (some are
read only, the rest are read/write), then by aligning them to
different cache line, they won't interfere to each other...since AFAIK
a write to  even one bit in a cache line will update the whole cache
line. Other data in the same cache line will stay, they will be just
rewritten AFAIK.

I hope my guess is right :)

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com