Date: Wed, 1 Mar 2017 21:54:32 -0800 From: Conrad Meyer <cem@freebsd.org> To: Bruce Evans <brde@optusnet.com.au> Cc: src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r313006 - in head: sys/conf sys/libkern sys/libkern/x86 sys/sys tests/sys/kern Message-ID: <CAG6CVpWG3xuNEF%2BRW4DG3HdLb=GgPKwapBLyq-kArRV%2B3fBcfQ@mail.gmail.com> In-Reply-To: <20170302162120.C8136@besplex.bde.org> References: <201701310326.v0V3QW30024375@repo.freebsd.org> <20170202184819.GP2092@kib.kiev.ua> <20170203062806.A2690@besplex.bde.org> <CAG6CVpV8fqMd82hjYoyDfO3f5P-x6%2B0OJDoQHtqXqY_tfWtZsA@mail.gmail.com> <20170228121335.Q2733@besplex.bde.org> <CAG6CVpWwZhMAsVB%2Bp-N0fMVOzzQSRaYonEfE-4Z6gv%2BLGuRn9w@mail.gmail.com> <20170302162120.C8136@besplex.bde.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Mar 1, 2017 at 9:27 PM, Bruce Evans <brde@optusnet.com.au> wrote: > On Wed, 1 Mar 2017, Conrad Meyer wrote: > >> On my laptop (Intel(R) Core(TM) i5-3320M CPU =E2=80=94 Ivy Bridge) I sti= ll 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 differen= ce > above size 3*LONG unless LONG is too small. Apparently it is too small f= or > 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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAG6CVpWG3xuNEF%2BRW4DG3HdLb=GgPKwapBLyq-kArRV%2B3fBcfQ>