On Thu, Dec 23, 2010 at 09:32:13AM +0000, Darren J Moffat wrote: > On 22/12/2010 20:27, Garrett D'Amore wrote: > >That said, some operations -- and cryptographic ones in particular -- > >may use floating point registers and operations because for some > >architectures (sun4u rings a bell) this can make certain expensive > > Well remembered! There are sun4u optimisations that use the > floating point unit but those only apply to the bignum code which in > kernel is only used by RSA. > > >operations go faster. I don't think this is the case for secure > >hash/message digest algorithms, but if you use ZFS encryption as found > >in Solaris 11 Express you might find that on certain systems these > >registers are used for performance reasons, either on the bulk crypto or > >on the keying operations. (More likely the latter, but my memory of > >these optimizations is still hazy.) > > RSA isn't used at all by ZFS encryption, everything is AES > (including key wrapping) and SHA256. > > So those optimistations for floating point don't come into play for > ZFS encryption.
Moreover, we have platform-specific crypto optimizations. If there were FPU operations that help speed up symmetric crypto on an M4000 but not on UltraSPARC T2s, then we'd use that on the one but not on the other. Nico -- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
