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Re: Intel microcode update and glibc HLE


On 09/27/2014 01:14 AM, Siddhesh Poyarekar wrote:
> On 27 September 2014 10:40, Carlos O'Donell <carlos@redhat.com> wrote:
>> It turns out to be more than just a configure flag.
>>
>> Andi's recent rwlock changes use TSX unconditionally.
> 
> I would reckon that it's wrong to do so. Not using
> --enable-lock-elision should disable all elision code.

I agree.

>> Similarly for ppc64 and s390 I think I'll make the flag do this:
>>
>> --enable-lock-elision=yes (enable for all machines)
>> --enable-lock-elisoin=x86_64,ppc64,s390x (enable for these machines)
> 
> Why do you need this?  Wouldn't it be sufficient to do this in
> distribution spec files?

We don't need it. We can indeed push it into the distribution
to handle there. However, the remaining problem is that upstream
will want a sensible default per-machine. I guess we can look at
refactoring this such that the machines can influence the default.

For example as the Intel elision code is tested more it might
default to being enabled by default sooner, while the ppc64 and s390x
would not.

Cheers,
Carlos.


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