GCC PARALLEL_MAKE changed

GCC PARALLEL_MAKE changed

[Vali Cobelea]

Hi,

We noticed that the GCC parallel make flag (PARALLEL_MAKE, located in 
"meta/recipes-devtools/gcc/gcc-cross-canadian_4.?.bb") got changed from 
"-j 32" to simply nothing.
We are wondering what was the reason for this change, which seems to 
have been made somewhere before the fall of 2012, while the GCC was 
around version 4.6 or earlier (for each we dont have the repository to 
track down the change).

After several builds where the compile time for GCC got measured, I can 
say that this flag indeed reduces the build time, when it is put at "-j 
32" (using a proper build machine).
In average the build time frame was reduced by 18%.

Much appreciated any thoughts on this, I know that it has been a while 
since this change happen.

Thank you very much,
Vali

Re: GCC PARALLEL_MAKE changed

[Khem Raj]

Vali

On Aug 8, 2013, at 12:55 AM, Vali Cobelea <valentin.cobelea@enea.com> wrote:

> Hi,
> 
> We noticed that the GCC parallel make flag (PARALLEL_MAKE, located in "meta/recipes-devtools/gcc/gcc-cross-canadian_4.?.bb") got changed from "-j 32" to simply nothing.
> We are wondering what was the reason for this change, which seems to have been made somewhere before the fall of 2012, while the GCC was around version 4.6 or earlier (for each we dont have the repository to track down the change).
> 
> After several builds where the compile time for GCC got measured, I can say that this flag indeed reduces the build time, when it is put at "-j 32" (using a proper build machine).
> In average the build time frame was reduced by 18%.
> 
> Much appreciated any thoughts on this, I know that it has been a while since this change happen.
> 


There were race conditions happening with the build. I have not verified if they have been fixed. However you could try
remove 

PARALLEL_MAKE = ""

from recipe and then it should respect the global -j value and see if this builds consistently. If it does
propose a patch to remove it

> Thank you very much,
> Vali
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