"use register arguments" option enabled.

Brian Gerst bgerst at didntduck.org
Tue May 17 12:19:07 UTC 2005


Mike Honeyfield wrote:
> On 5/17/05, Arjan van de Ven <arjanv at redhat.com> wrote:
> 
>>On Tue, 2005-05-17 at 10:45 +1200, Mike Honeyfield wrote:
>>
>>>On 5/17/05, Ignacio Vazquez-Abrams <ivazquez at ivazquez.net> wrote:
>>>
>>>>On Tue, 2005-05-17 at 10:29 +1200, Mike Honeyfield wrote:
>>>>
>>>>>I am just wondering the reasoning behind having the experimental
>>>>>option "Use register arguments" on in the kernel config.
>>>>>
>>>>>It has caused some issues for me, have since fixed it, but was
>>>>>wondering why an experimental feature that could/can break the ABI for
>>>>>3rd party binary only modules would be enabled?
>>>>
>>>>Speed. Pushing data onto the stack takes longer than just shoving it
>>>>into a register.
>>>>
>>>
>>>So the speed improvement is enough to justify this?
>>>
>>>I could understand Fedora Core's kernels have this feature, but was a
>>>bit suprised to see the same issue in RHEL.
>>
>>why?
>>
>>This only impacts binary modules, and in the process of porting those to
>>2.6 the vendor needs to "fix" this up just as well. That is the same for
>>FC and RHEL.
>>
> 
> 
> So you disagree that this is actually "experimental" as per the kernel config? 
> 
> Doesn't the term experimental indirectly imply possible stability
> issues? Not reasuring IMHO.

It is no longer experimental, even though the tag wasn't removed.  It 
was only marked experimental because old versions of GCC had bugs with 
respect to -mregparm.

--
				Brian Gerst




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