On Fri, Jan 25, 2013 at 3:41 PM, Julian Brooks <
jbeezez@gmail.com> wrote:
> Excuse my ignorance:
> not sure how to start the below version of pd on the rpi?
>
> I have the full path but then what?
>
> if I do (in command line)
> pd /place/where/new/pd/is/bin/pd
> It signals watchdog.
>
> I also still have regular pd 0.44.0 installed btw.
>
> Sorry if this is dumb dumb dumb dumb Duuummmbbb.
>
> Jb
>
> On 24 January 2013 09:14, katja <
katjavetter@gmail.com> wrote:
>>
>> 'Undenormalized' Pd build for Raspberry Pi is temporarily parked here
>> for testing purposes (will be removed when Miller's release is fixed
>> in this sense):
>>
>>
www.katjaas.nl/temp/pd-0.44-0-normalized.tar.gz
>>
>> This is a locally installed Pd, like Miller's distribution. You can
>> start it from command line with the full path to
>> pd-0.44-0-normalized/bin/pd. It's not a .deb, so it can't be installed
>> under supervision of package manager.
>>
>> Katja
>>
>>
>> On Wed, Jan 23, 2013 at 9:15 PM, Julian Brooks <
jbeezez@gmail.com> wrote:
>> > Hey Katja,
>> >
>> > Would you mind sharing the 'normalised' Pd-0.44.0 for RPi please.
>> >
>> > Cheers,
>> >
>> > Julian
>> >
>> >
>> >
>> > On 23 January 2013 18:23, katja <
katjavetter@gmail.com> wrote:
>> >>
>> >> Now I recompiled the Pd-0.44.0 release on Raspberry Pi (took me a few
>> >> hours, not only because Pi is so slow) with PD_BIGORSMALL enabled for
>> >> arm in m_pd.h. Using bigorsmalltest.pd from my previous mail I
>> >> verified that the macro is implemented indeed.
>> >>
>> >> Martin Brinkmann's patch chaosmonster1
>> >> (
http://www.martin-brinkmann.de) gives a beautiful illustration of the
>> >> improvement. This patch is full of filters and delay lines. At it's
>> >> initial settings, there is no subnormals problem. But if you set the
>> >> bottom slider to the right, it gets silent. With Pd-0.44-0 release,
>> >> CPU load explodes. With the 'normalized' Pd, nothing special happens.
>> >>
>> >> And indeed, the PD_BIGORSMALL conditional checks come for free: with
>> >> initial settings of the chaosmonster1, performance is equivalent in
>> >> both Pd's. Cool! Hopefully this is similar on armv7.
>> >>
>> >> Katja
>> >>
>> >>
>> >>
>> >> On Wed, Jan 23, 2013 at 5:01 PM, Hans-Christoph Steiner <
hans@at.or.at>
>> >> wrote:
>> >> >
>> >> > hey Katya,
>> >> >
>> >> > This also sounds like good evidence for your idea of writing C code
>> >> > that
>> >> > modern compilers optimize well. Using unions for aliasing allows the
>> >> > compiler
>> >> > to do all the new tricks, then writing loops that auto-vectorize
>> >> > gives
>> >> > us the
>> >> > real benefits. Also, I think we can see some gains by using memcpy()
>> >> > since on
>> >> > modern libc version, those are highly optimized for the given CPU,
>> >> > dynamically
>> >> > choosing the routines based on what instructions are available.
>> >> > memcpy
>> >> > will
>> >> > use things like SSSE2 if its available.
>> >> >
>> >> > .hc
>> >> >
>> >> > On 01/23/2013 07:47 AM, katja wrote:
>> >> >> Finally some good news on this topic. Earlier I stated that 'big or
>> >> >> small tests' are expensive for the Pi, but that is not by definition
>> >> >> the case. There must have been other conditions blurring my
>> >> >> impression. I've now done a systematic test where other influences
>> >> >> are
>> >> >> ruled out. A test class [lopass~] with exactly the same routine as
>> >> >> [lop~] was made, but compiled with PD_BIGORSMALL() macro enabled. It
>> >> >> was verified that [lopass~] is not affected by denormals.
>> >> >> Performance
>> >> >> comparison of [lop~] and [lopass~] shows that both objects cause
>> >> >> equivalent CPU load. Meaning, Raspberry Pi gives the 'big or small
>> >> >> checks' for free! At least in the case of this simple filter. Please
>> >> >> try attached bigorsmalltest.zip on the Pi to see if I'm not
>> >> >> dreaming.
>> >> >>
>> >> >> While I was at the topic anyway, I also tried a big or small test
>> >> >> with
>> >> >> union instead of direct type aliasing. It has the advantage that the
>> >> >> compiler can apply strict aliasing rules. This test with unions did
>> >> >> not cause extra CPU load either on the Pi. If you want to verify
>> >> >> this
>> >> >> result, enable the call to bigorsmall() instead of PD_BIGORSMALL in
>> >> >> lopass~.c and recompile.
>> >> >>
>> >> >> The fact that these tests do not cause extra CPU load, indicate that
>> >> >> they are done in parallel with other instructions. Float and int
>> >> >> registers are apparently strictly separated on armv6, there's no
>> >> >> such
>> >> >> thing like Intel's xmm registers or armv7's NEON. As it happens, the
>> >> >> big or small tests are done on ints, aliases of the floats that must
>> >> >> be tested. Initially I assumed that the transport of floats from vfp
>> >> >> to the arm integer processor would be expensive, but if the
>> >> >> instructions are done simultaneously it may be an advantage instead.
>> >> >> Another thing is that ARM implements branch predication instead of
>> >> >> branch prediction. Those terms look almost the same but the routines
>> >> >> are very different. Predication is when instructions for both
>> >> >> branches
>> >> >> are executed, and the wrong result is simply discarded later.
>> >> >>
>> >> >> Conclusions from the limited test with [lop~] and [lopass~] do not
>> >> >> mean that all sorts of conditional checks are cheap on the Pi, or on
>> >> >> ARM in general. If PD_BIGORSMALL is enabled for RPi using
>> >> >> compile-time
>> >> >> definition __arm__, it will also hold for armv7, but it may have
>> >> >> very
>> >> >> different result there. At the moment I have no access yet to an
>> >> >> armv7
>> >> >> device. Maybe someone can recompile test class [lopass~] and do the
>> >> >> tests on Beagleboard or Cubieboard? Otherwise I may be able to do it
>> >> >> on my friend's PengPod when that has arrived.
>> >> >>
>> >> >> Katja
>> >> >>
>> >> >>
>> >> >> On Tue, Jan 22, 2013 at 8:54 PM, Miller Puckette <
msp@ucsd.edu>
>> >> >> wrote:
>> >> >>> thanks - I'd better try this and find out what's going on :)
>> >> >>>
>> >> >>> M
>> >> >>>
>> >> >>> On Mon, Jan 21, 2013 at 11:54:29AM +0100, katja wrote:
>> >> >>>> Tried the 0.44.0 build from your website. It has the same issue
>> >> >>>> with
>> >> >>>> subnormal values. My test patch is with [lop~]. If inf or nan is
>> >> >>>> fed
>> >> >>>> into [lop~], these 'values' keep circulating in the object, it can
>> >> >>>> no
>> >> >>>> longer process normal signal values.
>> >> >>>>
>> >> >>>> I also tried my reverb stuff with specific compiler options for
>> >> >>>> Pi's
>> >> >>>> processor:
>> >> >>>>
>> >> >>>> -march=armv6zk
>> >> >>>> -mcpu=arm1176jzf-s
>> >> >>>> -mtune=arm1176jzf-s
>> >> >>>>
>> >> >>>> With these options, gcc should be able to decide that RunFast mode
>> >> >>>> is
>> >> >>>> permitted. But even in combination with -ffast-math (which in turn
>> >> >>>> sets -funsafe-math-optimizations and -fno-trapping-math amongst
>> >> >>>> others), denormals are still there. I'm literally out of options
>> >> >>>> for
>> >> >>>> the moment. Sorry for not having better news.
>> >> >>>>
>> >> >>>> Katja
>> >> >>>>
>> >> >>>>
>> >>
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>
>