John-Mark Gurney wrote this message on Tue, Feb 11, 2014 at 10:56 -0800: > I did some performance testing on sha256, and found that the libmd > version is significantly faster, ~20%, than the kernel version. Even > if you enable SHA2_UNROLL_TRANSFORM (which isn't the default), the > version in libmd is still faster. > > So, this patch moves libmd's sha256c.c and sha256.h into the kernel, > and adapts the userland to pull the version from the kernel. This > change removes sha256 from the existing sha2.c file, and does some > minor cleanup of types in sha2. > > I have tested this w/ ZFS using sha256 checksums, and a ZFS made > pre-patch is read fine by a kernel post patch. I have also run > the tests in lib/libmd and they all pass fine. Passes > buildworld/buildkernel/installkernel/reboot/installworld/reboot/test. > > Patch: > https://www.funkthat.com/~jmg/sha256.kern.patch > > Following stats are in seconds to digest 100000 10000-byte blocks, > calculated using sha256 -t: > $ ministat soft.times kernsoft.times > x soft.times > + kernsoft.times > +------------------------------------------------------------------------------+ > |x xx xx +++ + +| > | |___________AM_________| |_______M_____A______________| | > +------------------------------------------------------------------------------+ > N Min Max Median Avg Stddev > x 5 6.775387 8.279581 7.848128 7.792094 0.60912664 > + 5 8.997429 10.768921 9.090787 9.4359144 0.75040822 > Difference at 95.0% confidence > 1.64382 +/- 0.99674 > 21.096% +/- 12.7917% > (Student's t, pooled s = 0.683428) > > This is in preperation of bringing in an SSE4 accelerated version of > sha256 (for both userland and kernel) that sees a 2x performance > increase. Sorry, security@ != freebsd-security@... This is now going to the correct email.. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not." _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-security To unsubscribe, send any mail to "[email protected]"