Re: [RFC] kbuild: bpf: Do not run pahole with -j on 32bit userspace

[Jiri Slaby <jirislaby@kernel.org>]

On 26. 08. 24, 19:03, Arnaldo Carvalho de Melo wrote:
> On Mon, Aug 26, 2024 at 10:57:22AM +0200, Jiri Slaby wrote:
>> On 22. 08. 24, 17:24, Arnaldo Carvalho de Melo wrote:
>>> On Thu, Aug 22, 2024 at 11:55:05AM +0800, Shung-Hsi Yu wrote:
>>> I stumbled on this limitation as well when trying to build the kernel on
>>> a Libre Computer rk3399-pc board with only 4GiB of RAM, there I just
>>> created a swapfile and it managed to proceed, a bit slowly, but worked
>>> as well.
>>
>> Here, it hits the VM space limit (3 G).
> 
> right, in my case it was on a 64-bit system, so just not enough memory,
> not address space.
>   
>>> Please let me know if what is in the 'next' branch of:
> 
>>> https://git.kernel.org/pub/scm/devel/pahole/pahole.git
> 
>>> Works for you, that will be extra motivation to move it to the master
>>> branch and cut 1.28.
> 
>> on 64bit (-j1):
>> * master: 3.706 GB
>> (* master + my changes: 3.559 GB)
>> * next: 3.157 GB
>   
>> on 32bit:
>>   * master-j1: 2.445 GB
>>   * master-j16: 2.608 GB
>>   * master-j32: 2.811 GB
>>   * next-j1: 2.256 GB
>>   * next-j16: 2.401 GB
>>   * next-j32: 2.613 GB
>>
>> It's definitely better. So I think it could work now, if the thread count
>> was limited to 1 on 32bit. As building with -j10, -j20 randomly fails on
>> random machines (32bit processes only of course). Unlike -j1.
> 
> Cool, I just merged a patch from Alan Maguire that should help with the
> parallel case, would be able to test it? It is in the 'next' branch:

Not much helping.

On my box (as all previous runs):
next-j1 2.242
next-j16 2.808
next-j32 2.646

On a build host:
next-j1: 2.242
next-j16: 2.824
next-j20: 2.902 (crash)
next-j32: 2.902 (crash)

-- 
js
suse labs