On Wed, Mar 1, 2017 at 9:27 PM, Bruce Evans <b...@optusnet.com.au> wrote: > On Wed, 1 Mar 2017, Conrad Meyer wrote: > >> On my laptop (Intel(R) Core(TM) i5-3320M CPU — Ivy Bridge) I still see >> a little worse performance with this patch. Please excuse the ugly >> graphs, I don't have a better graphing tool set up at this time: >> >> https://people.freebsd.org/~cem/crc32/sse42_bde.png >> https://people.freebsd.org/~cem/crc32/sse42_bde_log.png > > > Try doubling the loop sizes. There shouldn't be any significant difference > above size 3*LONG unless LONG is too small. Apparently it is too small for > older CPUs. > > I now have a Sandybridge i5-2xxx laptop to test on, but don't have it set > up for much yet. > > Bruce
Hi Bruce, Doubling the loop sizes seems to make it slightly worse, actually: https://people.freebsd.org/~cem/crc32/sse42_bde2.png https://people.freebsd.org/~cem/crc32/sse42_bde_log2.png I haven't made any attempt to inspect the generated assembly. This is Clang 3.9.1 with -O2. Best, Conrad _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
