From: "Steve" <star@gmx.li>
To: poky@lists.yoctoproject.org
Subject: Re: [poky] gcc11.3 (?) optimization performance problems
Date: Fri, 25 Nov 2022 07:30:54 +0100 [thread overview]
Message-ID: <29907449-6772-0b9a-7fe7-9dec1a02decb@gmx.li> (raw)
In-Reply-To: <172A77114EC2E04B.11309@lists.yoctoproject.org>
Am 24.11.22 um 09:12 schrieb Steve:
> Am 23.11.22 um 20:52 schrieb Khem Raj:
>> On Wed, Nov 23, 2022 at 9:28 AM Steve <star@gmx.li> wrote:
>>>
>>> Hello, I switched my poky distro (and SDK to compile) to 4.0.5 - running
>>> an CortexA53 with 4 cores (before it was 4.0.0 I think).
>>> My test application simple average over an array of 5 million bytes
>>> takes now around 8 times as long as before.
>>>
>>> What is changed is gcc from 11.2 to 11.3. Can this be the reason?
>>
>> It can be. However we need to narrow it down. So perhaps just revert
>> the 11.3 upgrade
>> and leave everything else at yocto 4.0.5 and see if the behavior is
>> regressed.
>
> Building a SDK takes some time... seems I am wasting time building 4.0.1
> (gcc 11.2) and 4.0.5 (gcc11.3) clean again.
>
> I am not good in analyzing files, but compare the strings in my test
> binary tell me two differences: GNU AS 3.7 vs 3.8 and glibc 2.34-r0 vs
> 2.35-r0 (one is done with my "fast" SDK the other with 4.0.1)
>
> Digging into details, my "fast" SDK was created in yocto 3.4 (not as
> assumed in 4.0)
>
> How can I test that, simply exchange the binutils-recipe? Will that
> work? Can I really mix that version?
> How to do that 'revert'? Just copy a gcc recipe from an older or newer
> version? Finally it is not the compiler, but the cross compiler, right?
>
>
>>> Compiler options, eg -O3 keeps same. Is there indeed a regression?
>>>
>>> The speed neither depends on rootfs nor kernel. Just the compiler/SDK
>>> decides wether the compiled app is fast or slow.
>>
>> Right, there could be other factors as well. We do change other
>> packages too in
>> minor releases and it could be one of these which might have caused
>> the issue
>> as well but its better to go one by one.
Based on 4.0.5 I reverted first gcc recipe to what was in 3.4 and in a
second step binutuil.
The result keeps same. I am clueless and need your help please what to
check next. Any optimization that works only on a certain kernel that I
don't use maybe?
prev parent reply other threads:[~2022-11-25 6:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-23 17:28 [poky] gcc11.3 (?) optimization performance problems Steve
2022-11-23 19:52 ` Khem Raj
2022-11-24 8:12 ` Steve
[not found] ` <172A77114EC2E04B.11309@lists.yoctoproject.org>
2022-11-25 6:30 ` Steve [this message]
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