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Groups > comp.lang.forth > #17646

Re: DTC

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Re: DTC
Date 2012-11-28 18:12 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2012Nov28.191254@mips.complang.tuwien.ac.at> (permalink)
References (5 earlier) <EPedneRds5eqtivNnZ2dnUVZ8rGdnZ2d@supernews.com> <2012Nov28.173609@mips.complang.tuwien.ac.at> <3_idnYfdWuwR3ivNnZ2dnUVZ8tadnZ2d@supernews.com> <2012Nov28.181355@mips.complang.tuwien.ac.at> <25KdnaK6jvpvzCvNnZ2dnUVZ8radnZ2d@supernews.com>

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Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>>>Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>> 
>>>Besides, last time I looked the only penalty was for a write
>>>to the same cache line as the code; that's irrelevant here.
>> 
>> I guess that myopic view is what causes the persistence of this
>> problem. 
>
>In what way is this view "myopic"?  It is true.
>
>> Now consider:
>> 
>> variable foo
>> 1 constant bar
>> variable boing
>> : flip bar foo ! bar boing ! ;
>> flip
>
>BOING is a variable.  The problem is that BOING's data shares a cache
>line with some code.  That's irrelevant here: we're talking about
>constants.  Their data, which does not change, may be freely mixed
>with code.

It's myopic, because it looks only at the constant, as if it existed
in isolation.  So I show an example with some surroundings, and you
insist that the surroundings are irrelevant.  They are not.  They are
the reason why bigForth is 5 times slower then Gforth on cd16sim and
about 3 times for brew.

>If a processor prefetches you have to consider its accesses beyond
>those explicitly written, but the issue is still that of code and
>writable data in the same cache line.

No, the code and the data can be in different cache lines, and you can
still have cache consistency overhead.  Also, on older processors (P5,
K6) even read-only data caused this problem.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2012: http://www.euroforth.org/ef12/

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Thread

DTC Mark Wills <forthfreak@gmail.com> - 2012-11-27 08:01 -0800
  Re: DTC Paul Rubin <no.email@nospam.invalid> - 2012-11-27 08:55 -0800
    Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-27 09:01 -0800
  Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-11-27 17:42 -0800
    Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-27 23:50 -0800
      Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 04:41 -0600
        Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-28 02:48 -0800
          Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 05:27 -0600
            Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-28 03:51 -0800
              Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-11-28 21:56 -0800
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-29 01:26 -0800
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-11-29 22:34 -0800
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-30 01:42 -0800
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-11-30 13:18 -0800
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-01 01:42 -0800
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-12-03 15:25 -0800
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-12-03 16:18 -0800
                Re: DTC "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-12-03 21:20 -0500
                Re: DTC "Elizabeth D. Rather" <erather@forth.com> - 2012-12-03 17:29 -1000
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-04 00:12 -0800
                Re: DTC Paul Rubin <no.email@nospam.invalid> - 2012-12-05 11:35 -0800
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-12-04 20:17 -0800
                Re: DTC Ron Aaron <rambamist@gmail.com> - 2012-12-05 08:31 +0200
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-04 23:48 -0800
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-04 23:53 -0800
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-12-05 12:13 -0800
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-12-05 15:26 -0800
                Re: DTC Ron Aaron <rambamist@gmail.com> - 2012-12-06 06:32 +0200
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-06 01:07 -0800
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-12-06 04:23 -0800
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-06 15:49 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-06 07:42 -0800
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-12-06 08:30 -0800
                Re: DTC Paul Rubin <no.email@nospam.invalid> - 2012-12-06 09:45 -0800
                Re: DTC albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-12-06 21:41 +0000
                Re: DTC "A. K." <akk@nospam.org> - 2012-12-06 23:15 +0100
                Re: DTC albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-12-08 01:27 +0000
                Re: DTC "A. K." <akk@nospam.org> - 2012-12-08 11:19 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-08 03:55 -0800
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-08 13:44 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-08 06:05 -0800
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-08 18:35 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-08 11:20 -0800
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-09 01:01 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-08 06:10 -0800
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-08 18:57 +0100
                Re: DTC "A. K." <akk@nospam.org> - 2012-12-08 19:46 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-08 11:23 -0800
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-08 13:37 +0100
                Re: DTC "A. K." <akk@nospam.org> - 2012-12-08 14:41 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-08 06:15 -0800
                Re: DTC "A. K." <akk@nospam.org> - 2012-12-08 17:07 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-06 14:16 -0800
                Re: DTC Brad Eckert <hwfwguy@gmail.com> - 2012-12-07 09:00 -0800
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-06 14:21 -0800
                Re: DTC "Elizabeth D. Rather" <erather@forth.com> - 2012-12-06 08:01 -1000
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-06 14:18 -0800
                Re: DTC "Elizabeth D. Rather" <erather@forth.com> - 2012-12-06 13:48 -1000
                Re: DTC "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-12-06 19:03 -0500
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-12-07 02:59 -0800
                Re: DTC albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-12-06 13:13 +0000
                Re: DTC "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-12-05 20:39 -0500
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-06 15:46 +0100
                Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-12-06 07:47 -0800
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-12-06 08:36 -0800
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-12-05 04:03 -0800
                Re: DTC "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2012-12-06 20:30 -0800
                Re: DTC David Thompson <dave.thompson2@verizon.net> - 2012-12-11 23:52 -0500
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-12-12 10:59 -0800
                Re: DTC David Thompson <dave.thompson2@verizon.net> - 2012-12-31 02:43 -0500
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2013-01-02 00:44 -0800
            Re: DTC albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-11-28 13:54 +0000
              Re: DTC "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2012-12-06 20:16 -0800
    Re: DTC "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-11-28 06:58 -0500
      Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-28 04:50 -0800
        Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 07:08 -0600
          Re: DTC Mark Wills <forthfreak@gmail.com> - 2012-11-28 06:02 -0800
            Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 08:23 -0600
          Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-28 14:18 +0000
            Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 08:32 -0600
              Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-28 15:00 +0000
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 09:18 -0600
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-28 16:36 +0000
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 11:02 -0600
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-28 17:13 +0000
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 12:03 -0600
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-28 18:12 +0000
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-28 12:32 -0600
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-29 14:30 +0000
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-11-29 18:05 +0100
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-11-29 11:19 -0800
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-30 03:14 -0600
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-30 14:12 +0000
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-30 10:32 -0600
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-30 16:40 +0000
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-12-01 15:34 +0000
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-01 21:23 +0100
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-12-03 16:28 +0000
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-03 18:44 +0100
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-12-03 04:50 -0600
                Re: DTC Bernd Paysan <bernd.paysan@gmx.de> - 2012-12-03 16:48 +0100
                Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-12-03 15:59 +0000
                Re: DTC albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-11-30 15:34 +0000
                Re: DTC Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-11-30 10:36 -0600
                Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-11-30 12:47 -0800
                Re: DTC Alex McDonald <blog@rivadpm.com> - 2012-11-28 11:29 -0800
        Re: DTC "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-11-29 04:15 -0500
          Re: DTC "Elizabeth D. Rather" <erather@forth.com> - 2012-11-29 08:52 -1000
      Re: DTC Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-11-28 22:25 -0800
        Re: DTC "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-11-29 04:12 -0500
  Re: DTC humptydumpty <ouatubi@gmail.com> - 2012-11-28 02:04 -0800
  Re: DTC anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-28 14:21 +0000

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