Re: [PATCH v1 2/2] perf auxtrace: Optimize barriers with load-acquire and store-release

[Peter Zijlstra]

On Tue, Jun 01, 2021 at 12:45:16PM +0300, Adrian Hunter wrote:
> On 1/06/21 12:17 pm, Peter Zijlstra wrote:
> > On Tue, Jun 01, 2021 at 12:07:31PM +0300, Adrian Hunter wrote:
> >> __sync_xxx_compare_and_swap is out-of-date now. This page:
> >>
> >> https://gcc.gnu.org/onlinedocs/gcc/_005f_005fsync-Builtins.html#g_t_005f_005fsync-Builtins
> >>
> >> recommends '__atomic' builtins instead.
> > 
> > perf doesn't seem to use that.
> 
> I guess we could drop support for the compat case; add validation:
> 
> "Error, 32-bit perf cannot record AUX area traces from a 64-bit kernel.
> Please use a 64-bit version of perf instead."

For AUX, possibly, sadly the exact same problem exists for the normal
buffer IIRC.