Re: GA144 article

From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	comp.lang.forth
Subject	Re: GA144 article
References	(15 earlier) <c999b0ef-d293-4ebd-9a2d-e76eb0cb73cb@googlegroups.com> <7xy5lw985e.fsf@ruckus.brouhaha.com> <407431d3-e67e-4344-aae9-7098856d4ff3@googlegroups.com> <7x8vdw3q3m.fsf@ruckus.brouhaha.com> <bf496233-0aaf-4103-b9a8-0ed6ecc65d32@googlegroups.com>
Date	2012-08-05 15:50 -0700
Message-ID	<7xy5lt3qe6.fsf@ruckus.brouhaha.com> (permalink)
Organization	Nightsong/Fort GNOX

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rickman <gnuarm@gmail.com> writes:
> Your calculations make no sense to me.  Sorry, but unless you can
> explain them a bit more I have no idea why you are adding the numbers
> you are adding.  I'm not even sure what the resulting number is an
> estimate of.

Simply this.  Reading from a port adds an average amount of time T=X+Y
to the total runtime of the program.  X is the time for the port read
itself, typically 3.5ns according to the doc you quoted.  Y is the
instruction fetch time, that we don't know precisely (averaged across
the different programs that people would actually write) but about which
we have some information.  So I tried to estimate it imprecisely.  If it
makes you feel better, just set Y=0 which means T=3.5 ns.  Remember the
issue that led to this was comparing wire nodes in a GA144 to routing in
an FPGA.  I'd like to know how 3.5ns compares to FPGA routing.

Keep in mind also that the F18 node is a tiny microprocessor with a lot
of gates switching on each instruction (I believe there is an internal
microtick several times faster than the 700 mhz instruction cycle).
Every time a gate switches, power is dissipated.  Compare that to FPGA
routing, which I'd expect to be static (gates configured at
initialization time then left alone).  So those wire nodes are burning
more power than FPGA routing too.

On the other hand, the active nodes do a lot more than an FPGA CLB does,
so there is a trade-off.

> Read the timing section of the GA144 data book, DB002, sec 5.3 Typical
> Instruction Timings.

Thanks, that's useful info.

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Re: GA144 article Daniel Kalny <dkalny@seznam.cz> - 2012-07-24 02:37 -0700
  Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-24 03:12 -0700
    Re: GA144 article stephenXXX@mpeforth.com (Stephen Pelc) - 2012-07-24 10:36 +0000
      Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-24 10:28 -0700
        Re: GA144 article Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-07-24 22:12 +0000
    Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-24 14:49 -0700
      Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-26 13:25 -0700
        Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-27 13:17 -0700
          Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-27 14:31 -0700
            Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-27 22:02 -0700
              Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-28 23:03 -0700
                Re: GA144 article marko <marko@marko.marko> - 2012-07-30 09:12 +1000
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 01:09 -0700
                Re: GA144 article marko <marko@marko.marko> - 2012-08-01 00:19 +1000
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 09:59 -0700
                Re: GA144 article marko <marko@marko.marko> - 2012-08-01 10:13 +1000
                Re: GA144 article Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-01 00:59 +0200
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 16:54 -0700
                Re: GA144 article Luca Saiu <positron@gnu.org> - 2012-08-04 10:46 +0200
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-05 11:04 -0700
                Re: GA144 article Luca Saiu <positron@gnu.org> - 2012-08-06 02:02 +0200
                Re: GA144 article Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-06 02:16 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-30 08:23 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-30 21:33 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 01:51 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-31 11:48 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 14:54 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-31 16:09 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-01 12:57 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-01 14:16 -0700
                Re: GA144 article vandys@vsta.org - 2012-08-01 22:32 +0000
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-01 16:03 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-01 16:13 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-01 16:10 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-01 22:18 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-02 11:47 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-02 14:32 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-02 16:01 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-02 16:38 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-03 08:40 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-03 09:19 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-03 11:15 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-05 15:50 -0700
                Re: GA144 article Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-06 02:21 -0700

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