From: Robert Lipe <robertlipe@usa.net>
To: Alfred Perlstein <bright@rush.net>
Cc: egcs@egcs.cygnus.com
Subject: Re: optimization hints?
Date: Fri, 11 Jun 1999 06:08:00 -0000 [thread overview]
Message-ID: <19990611080747.G926@rjlhome.sco.com> (raw)
In-Reply-To: <Pine.BSF.3.96.990611035502.14320R-100000@cygnus.rush.net>
> It has always seemed weird that C, the langue usually chosen because
> it's closeness to the machine level wouldn't have a hint like
> system for doing branches.
> [ munch ]
> I was hoping to be able to tell it that this code isn't likely to
> execute and perhaps even move it someplace else to maximize the
> instruction cache utilization of my code.
It sounds like you're asking about runtime directed feedback
optimizations.
They can make a huge win on code by reducing paging, reducing cache
footprint, improving burst read/pipelining, improving branch prediction,
and so on. It's really quite amazing to watch such an optimizer run
around your basic blocks, flipping the polarity of tests, gluing "hot
spots" together, and so on.
In SCO parlance, one such utility is 'fur', the FUnction Rearranger.
http://uw7doc.sco.com/SDK_cdebug/_Using_fur_to_Perform_Block_Prof.html
WARNING: multiple messages have this Message-ID
From: Robert Lipe <robertlipe@usa.net>
To: Alfred Perlstein <bright@rush.net>
Cc: egcs@egcs.cygnus.com
Subject: Re: optimization hints?
Date: Wed, 30 Jun 1999 15:43:00 -0000 [thread overview]
Message-ID: <19990611080747.G926@rjlhome.sco.com> (raw)
Message-ID: <19990630154300._ytoeLlRpGfJn_CyI5puRC_ye7iLBOfCLGoU-CHrvJE@z> (raw)
In-Reply-To: <Pine.BSF.3.96.990611035502.14320R-100000@cygnus.rush.net>
> It has always seemed weird that C, the langue usually chosen because
> it's closeness to the machine level wouldn't have a hint like
> system for doing branches.
> [ munch ]
> I was hoping to be able to tell it that this code isn't likely to
> execute and perhaps even move it someplace else to maximize the
> instruction cache utilization of my code.
It sounds like you're asking about runtime directed feedback
optimizations.
They can make a huge win on code by reducing paging, reducing cache
footprint, improving burst read/pipelining, improving branch prediction,
and so on. It's really quite amazing to watch such an optimizer run
around your basic blocks, flipping the polarity of tests, gluing "hot
spots" together, and so on.
In SCO parlance, one such utility is 'fur', the FUnction Rearranger.
http://uw7doc.sco.com/SDK_cdebug/_Using_fur_to_Perform_Block_Prof.html
next prev parent reply other threads:[~1999-06-11 6:08 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-06-11 1:47 Alfred Perlstein
1999-06-11 1:58 ` Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-11 6:08 ` Robert Lipe [this message]
1999-06-11 9:12 ` Joe Buck
1999-06-30 15:43 ` Joe Buck
1999-06-11 18:28 ` Benjamin Scherrey
1999-06-11 19:17 ` Robert Lipe
1999-06-30 15:43 ` Robert Lipe
1999-06-30 15:43 ` Benjamin Scherrey
1999-06-30 15:43 ` Robert Lipe
1999-06-30 15:43 ` Alfred Perlstein
1999-06-11 10:34 Mike Stump
1999-06-16 9:42 ` Alfred Perlstein
1999-06-30 15:43 ` Alfred Perlstein
1999-06-30 15:43 ` Mike Stump
1999-06-11 16:50 Alex Rosenberg
1999-06-30 15:43 ` Alex Rosenberg
1999-06-11 17:43 Mike Stump
1999-06-30 15:43 ` Mike Stump
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