On Sat, Aug 6, 2011 at 10:56 AM, Mulyadi Santosa <[email protected]>wrote:
> On Sat, Aug 6, 2011 at 23:59, subin gangadharan > <[email protected]> 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 :) > Thanks for your quick reply.I have one more question. So in case of processor with read/write granularity of 4 byte access,just for understanding purpose imagine it's with out cache.So in that case any difference is there between 4byte and other 8byte,16 byte alignment. > > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer and consultant > > blog: the-hydra.blogspot.com > training: mulyaditraining.blogspot.com > -- With Regards Subin Gangadharan Everything should be made as simple as possible,but not simpler.
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