Messages in this thread | | | From | "Arnaldo Carvalho de Melo" <> | Date | Mon, 26 Nov 2007 22:40:16 -0200 | Subject | Re: [RFC] Documentation about unaligned memory access |
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Em Mon, Nov 26, 2007 at 03:47:06PM +0100, Johannes Berg escreveu: > > > Sidenote: in the above example, you may wish to reorder the fields in the > > above structure so that the overall structure uses less memory. For example, > > moving field3 to sit inbetween field1 and field2 (where the padding is > > inserted) would shrink the overall structure by 1 byte: > > > > struct foo { > > u16 field1; > > u8 field3; > > u32 field2; > > }; > > You can reorder to u32, u16, u8 order and save another byte :) > > A reference to pahole could be appropriate here, and probably a small > note that some large existing structures like netdev have deliberate > holes to achieve cache alignment.
shameless plug:
https://ols2006.108.redhat.com/2007/Reprints/melo-Reprint.pdf
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