[LLVMdev] [Proposal] Parallelize post-IPO stage.

[Shuxin Yang]

On 7/16/13 2:04 PM, Xinliang David Li wrote:
> On Tue, Jul 16, 2013 at 1:49 PM, Shuxin Yang <shuxin.llvm at gmail.com> wrote:
>> I have actually came up the 3 approaches to build the post-ipo object
>> independently.
>>
>> The "3rd approach" here is the 1st solution in my original proposal. Almost
>> all coworkers call it sucks:-)
>> Now I accept it because the it has no way to be adaptive.
>>
>> Consider the scenario we compile the llvm compiler. We use "make -j16" for
>> computer with 8 processor, each make-thread invoke a compiler which may
>> blindly invoke 16 threads!
>> So, we end up to have 16*16 threads.
>>
> Determining the right parallelism is not the job of the compiler
> (builtin) nor that of a developer -- the underlying build system
> should take care of the scheduling :)
>
> David
>
>
>
People told me we have some magic lib which is able to figure out how 
heavy the
system is.  Compiler just need to link against them.  I have not yet got 
chance
to try these libs, neither do I know their names at this moment.

Since how to compiler post-LTO is small part of this project,  I'd like 
to pick up
whichever easier first. We may (very likely) end up all these possible 
three approaches.