Re: OO dispatch

From	Andrew Haley <andrew29@littlepinkcloud.invalid>
Subject	Re: OO dispatch
Newsgroups	comp.lang.forth
References	(11 earlier) <2013May16.160704@mips.complang.tuwien.ac.at> <ut-dnUpWOM9YygrMnZ2dnUVZ_t-dnZ2d@supernews.com> <2013May20.132840@mips.complang.tuwien.ac.at> <PeCdnUcty9HjsQfMnZ2dnUVZ_i2dnZ2d@supernews.com> <knec2u$nd9$1@online.de>
Message-ID	<FIKdnTQMndrwswbMnZ2dnUVZ_omdnZ2d@supernews.com> (permalink)
Date	2013-05-21 03:21 -0500

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Bernd Paysan <bernd.paysan@gmx.de> wrote:
> Andrew Haley wrote:
>> In the monomorphic case, an inline cache will predict perfectly unless
>> something changes.  An indirect branch predictor will predict
>> perfectly unless something changes or the entry has expired from its
>> cache, which is of limited size.
> 
> Actually, things are more complicated/sophisticated today.  The BTB
> is used to predict direct branches, too.  Why?  Because the decoder
> needs several pipeline stages to figure out where it actually goes
> to, but it wants to fetch the next instruction bundle as soon as
> possible, optimally back-to- back (so that you can do one branch per
> cycle).  So you now have the "code warming up"-effect on direct
> branches, too.  It's just that the hit for misprediction is probably
> lower, because the correct target is known a little bit earlier.

Right, but what has that to do with my point?

Andrew.

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Thread

Re: The current object Bernd Paysan <bernd.paysan@gmx.de> - 2013-05-15 16:46 +0200
  Re: The current object Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-15 13:11 -0500
    Re: The current object Bernd Paysan <bernd.paysan@gmx.de> - 2013-05-15 23:23 +0200
      Re: The current object Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-16 02:24 -0500
        Re: The current object anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-16 13:55 +0000
        Re: The current object Bernd Paysan <bernd.paysan@gmx.de> - 2013-05-16 17:45 +0200
          Re: The current object Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-18 05:13 -0500
            Re: The current object Doug Hoffman <glidedog@gmail.com> - 2013-05-18 06:43 -0400
            Re: The current object Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-18 10:03 -0500
              Re: The current object Doug Hoffman <glidedog@gmail.com> - 2013-05-18 11:30 -0400
              Re: The current object Bernd Paysan <bernd.paysan@gmx.de> - 2013-05-19 01:20 +0200
                Re: The current object Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-19 12:33 -0500
            Re: The current object Bernd Paysan <bernd.paysan@gmx.de> - 2013-05-19 01:07 +0200
              Re: The current object Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-19 03:58 -0500
    OO dispatch (was: The current object) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-16 14:07 +0000
      Re: OO dispatch Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-18 05:28 -0500
        Re: OO dispatch anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-20 11:28 +0000
          Re: OO dispatch Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-20 09:00 -0500
            Re: OO dispatch Bernd Paysan <bernd.paysan@gmx.de> - 2013-05-21 01:37 +0200
              Re: OO dispatch Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-21 03:21 -0500
            Re: OO dispatch anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-21 12:24 +0000
              Re: OO dispatch Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-21 10:18 -0500
                Re: OO dispatch anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-21 16:03 +0000
                Re: OO dispatch Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-05-21 12:55 -0500
                Re: OO dispatch Bernd Paysan <bernd.paysan@gmx.de> - 2013-05-29 00:00 +0200
                Re: OO dispatch Mark Wills <markrobertwills@yahoo.co.uk> - 2013-05-28 15:49 -0700

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