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digitalmars.D - Slashdot article about multicore

reply Brian <digitalmars brianguertin.com> writes:
"Windows and Linux Not Well Prepared For Multicore Chips"
http://developers.slashdot.org/article.pl?sid=09/03/22/193205&from=rss

I wouldn't completely agree that operating systems aren't ready for such 
things.

One of the comments reads: "This is the kind of the the compiler could do 
just fine ... by isolating parts of the code in which there are no 
dependencies in the data-flow, and which could therefore run in 
parallel..."

This sounds like what "pure" functions are going to be for, right?
Mar 22 2009
next sibling parent reply Jarrett Billingsley <jarrett.billingsley gmail.com> writes:
On Sun, Mar 22, 2009 at 9:55 PM, Brian <digitalmars brianguertin.com> wrote:

 "Windows and Linux Not Well Prepared For Multicore Chips"
 http://developers.slashdot.org/article.pl?sid=09/03/22/193205&from=rss

 I wouldn't completely agree that operating systems aren't ready for such
 things.

 One of the comments reads: "This is the kind of the the compiler could do
 just fine ... by isolating parts of the code in which there are no
 dependencies in the data-flow, and which could therefore run in
 parallel..."

 This sounds like what "pure" functions are going to be for, right?


That's more or less exactly what they're for.
Mar 22 2009
parent Walter Bright <newshound1 digitalmars.com> writes:
Jarrett Billingsley wrote:

 On Sun, Mar 22, 2009 at 9:55 PM, Brian <digitalmars brianguertin.com> wrote:

 This sounds like what "pure" functions are going to be for, right?


 That's more or less exactly what they're for.


Only partially. Pure functions are also a valuable tool to aid in 
modularizing code and self-documenting that it is modularized. Pure 
functions have some minor optimization benefits.
Mar 22 2009
prev sibling parent reply "Robert Jacques" <sandford jhu.edu> writes:
On Sun, 22 Mar 2009 21:55:04 -0400, Brian <digitalmars brianguertin.com>  
wrote:


 "Windows and Linux Not Well Prepared For Multicore Chips"
 http://developers.slashdot.org/article.pl?sid=09/03/22/193205&from=rss

 I wouldn't completely agree that operating systems aren't ready for such
 things.

 One of the comments reads: "This is the kind of the the compiler could do
 just fine ... by isolating parts of the code in which there are no
 dependencies in the data-flow, and which could therefore run in
 parallel..."

 This sounds like what "pure" functions are going to be for, right?


Yes and No. No, what they are talking about is a parallelizing compiler.  
i.e. one that performs automatic parallelization / code analysis, which  
for the most part doesn't work because it has no grantees. And yes, pure  
is all about giving the complier the grantees it needs to actually  
automatically parallelize the code.
Mar 22 2009
parent "Robert Jacques" <sandford jhu.edu> writes:
On Sun, 22 Mar 2009 22:09:53 -0400, Robert Jacques <sandford jhu.edu>  
wrote:


 On Sun, 22 Mar 2009 21:55:04 -0400, Brian <digitalmars brianguertin.com>  
 wrote:


 "Windows and Linux Not Well Prepared For Multicore Chips"
 http://developers.slashdot.org/article.pl?sid=09/03/22/193205&from=rss

 I wouldn't completely agree that operating systems aren't ready for such
 things.

 One of the comments reads: "This is the kind of the the compiler could  
 do
 just fine ... by isolating parts of the code in which there are no
 dependencies in the data-flow, and which could therefore run in
 parallel..."

 This sounds like what "pure" functions are going to be for, right?


 Yes and No. No, what they are talking about is a parallelizing compiler.  
 i.e. one that performs automatic parallelization / code analysis, which  
 for the most part doesn't work because it has no grantees. And yes, pure  
 is all about giving the complier the grantees it needs to actually  
 automatically parallelize the code.


Okay, next time I should read TFA before posting. What the author is  
talking about isn't pure or parallelizing compilers. What he's actually  
talking about is adding parallel instructions to the CPU. (The focus was  
on Itanium (which exchanged out-of-order execution for compiler controlled  
parallel instructions), though it could easily apply to the next SSE  
instruction set (specifically the one coming with larrabee) which  
primarily adds conditional tests and an execution mask. These allow for  
SIMD flow control (and have been in GPUs for a while) )
Mar 22 2009