On 03/01/2017 02:04 PM, Milan Broz wrote: > On 03/01/2017 01:42 PM, Gilad Ben-Yossef wrote: > ... > >> I can certainly understand if you don't wont to take the patch until >> we have results with >> dm-crypt itself but the difference between 8 separate invocation of >> the engine for 512 >> bytes of XTS and a single invocation for 4KB are pretty big. > > Yes, I know it. But the same can be achieved if we just implement > 4k sector encryption in dmcrypt. It is incompatible with LUKS1 > (but next LUKS version will support it) but I think this is not > a problem for now. > > If the underlying device supports atomic write of 4k sectors, then > there should not be a problem. > > This is one of the speed-up I would like to compare with the IV approach, > because everyone should benefit from 4k sectors in the end. > And no crypto API changes are needed here. > > (I have an old patch for this, so I will try to revive it.) If anyone interested, simple experimental patch for larger sector size (up to the page size) for dmcrypt is in this branch: http://git.kernel.org/cgit/linux/kernel/git/mbroz/linux.git/log/?h=dm-crypt-4k-sector It would be nice to check what performance gain could be provided by this simple approach. Milan
