Date: Sun, 18 Dec 2011 20:58:39 -0800 From: Adrian Chadd <adrian@freebsd.org> To: Stefan Bethke <stb@lassitu.de> Cc: Oleksandr Tymoshenko <gonzo@freebsd.org>, "freebsd-embedded@freebsd.org" <freebsd-embedded@freebsd.org> Subject: Re: Updated switch/glue patch? Message-ID: <CAJ-Vmok3MQmwBd8x4s8aeVQLavNNGY0v2eT_-pLj1eRpvQi1dw@mail.gmail.com> In-Reply-To: <18CABB46-9B9A-41CB-8742-6723C5FF4D67@lassitu.de> References: <CAJ-Vmon8%2BOXQ4g752zZEB-O0BR0sFWO0QUvw--xp2jsBDkx6tQ@mail.gmail.com> <0F6CC18F-6973-42A2-AC03-F01BF59458AE@lassitu.de> <CAJ-Vmo=Y8pp4iFnw%2B1hcPae6QXFboz=a7puwgC1kVSZ3JwMgPQ@mail.gmail.com> <1100F70E-9DA9-4163-AC9A-423ECE5AA9A3@lassitu.de> <CAJ-VmonrnJ7cC6u2LsL9AGusz_%2BkSwY62Rr1__sg5U_NynJ1SQ@mail.gmail.com> <CAJ-Vmo=WSN1oLM=B2HqSHrWyOaOD9BSwwu8=1Wys0CLRJ_N-TA@mail.gmail.com> <C637C171-A1A2-4296-84FA-6DE97137DC42@lassitu.de> <CAJ-Vmon2boy7OCh_4O0MeCi0yCdZu0OYb5dxHCEK=-%2B46zBGtg@mail.gmail.com> <CAJ-Vmoku5eLEYi5_DXVxK=0=4Ewn2aGepv3YUw4ApuVh_7y2%2Bw@mail.gmail.com> <CAJ-VmonvpnaS1rAO%2BsDRh1E5WfsrZTYE297Kc96prhfKjrM89Q@mail.gmail.com> <CAJ-VmokQxQs2DUKL=ONyxnnS7Q28ytmwZJ_thqvc4SvMkmS=cQ@mail.gmail.com> <18CABB46-9B9A-41CB-8742-6723C5FF4D67@lassitu.de>
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On 18 December 2011 02:17, Stefan Bethke <stb@lassitu.de> wrote: >> Erm, surely that's a bit ridiculous.. surely the locking doesn't need >> to be that fine grained _and_ multi-levelled. There has to be a better >> way to do this. :) > > Exactly. > > I've reimplemented iicbb.c to be slightly more protocol compliant, and to= be able to tune transfer speeds to the actual hardware capabilities. =A0I'= ve timed a single GETSCL (with WITNESS) to 8.7 microseconds, clearly that w= on't do. Ok. I'll check it out soon. > I think I'll look at gpio next, as you have, and see if the overhead can = be reduced. In the meantime, would you mind grabbing the latest code from my git tree (in the work/ath branch) and basing your work off of that? Even with delay=3D10 (the current hardcoded default), it takes up significantly less CPU than before. If we can debug and test this locking hacking and my iicbb changes (which are less intrusive than yours, which I'll review soon and we can merge in later), I'll push this into -HEAD so we can continue shaving off cycles and fixing things up. Thanks again Stefan! Adrian
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