Re: Re: RISC-V Bootstrap problems

["juzhe.zhong@rivai.ai" <juzhe.zhong@rivai.ai>]

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Besides, we don't have compilation issues in crossing-compiling (with segment intrinsics).
But I do agree we need to address such issue.

As far as I known, GCC compile insn-emit in single thread single core.
Can we multi-thread && multi-core to compile it to speed up the compilation?

Thanks.


juzhe.zhong@rivai.ai
 
From: Jeff Law
Date: 2023-05-25 11:43
To: Palmer Dabbelt; Vineet Gupta
CC: kito.cheng; gcc-patches; Kito Cheng; Patrick O'Neill; Jeff Law; macro; juzhe.zhong@rivai.ai
Subject: Re: RISC-V Bootstrap problems
 
 
On 5/24/23 17:13, Palmer Dabbelt wrote:
> On Wed, 24 May 2023 16:12:20 PDT (-0700), Vineet Gupta wrote:
 
[ ... big snip ... ]
 
>>
>> Never mind. Looks like I found the issue - with just trial and error and
>> no idea of how this stuff works.
>> The torture-{init,finish} needs to be in riscv.exp not rvv.exp
>> Running full tests now.
> 
> Thanks!
Marginally related.  I was able to bisect the "hang" when 3-staging the 
trunk on RISC-V with qemu user mode emulation.
 
So it wasn't actually hanging, but after the introduction of segment 
intrinsics the compilation time for insn-emit explodes -- previously I 
could do a full 3-stage bootstrap, build the glibc & the kernel, then 
test c/c++/fortran in ~10 hours.
 
Now just building insn-emit.o alone takes ~10 hours in that environment. 
  I suspect (but have not yet confirmed) that we should see a huge 
compile-time spike in cross builds as well, though obviously it won't be 
as bad since we're not using qemu emulation.
 
Clearly something isn't scaling well.  I don't know if we've got a crazy 
large function in there, a crazy number of functions or something that's 
just triggering a compile-time scaling problem.  Whatever it is, we 
probably need to address it.
 
jeff