Re: [PATCH] Cache aligned locks for PPC64

[Steve Munroe <sjmunroe us ibm com>]

Daniel Jacobowitz writes:

> On Tue, May 13, 2003 at 01:28:58PM -0500, Steve Munroe wrote:
>> Daniel Jacobowitz writes:
>> 
>>>  Um... this represents an ABI change for PowerPC32.  I don't believe
> >> you can just do this.  Anything with a lock declared in a structure 
>>> will break.
>> 
>> This is for compatibility with exist linuxthread binaries?
>
> Right.

mmmmm tricky. 

It is simple to leave powerpc32 unchanged but powerpc64 requires more 
thought. We must assume exiting PPC64 application binaries for glibc-2.2.5 
and linuxthreads. These applications should run (as is) on a new system 
that defaults to glibc-2.3.x NPTL.

I was also assuming that only NPTL would change while linuxthreads used 
the original alignment (compatible with 2.2.5). But also can create 
problems ...

I assume this means either not changing the alignment (and leaving big 
performance on the table) or using symver and building 2 libraries?