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Re: Intel microcode update and glibc HLE
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: Siddhesh Poyarekar <siddhesh dot poyarekar at gmail dot com>
- Cc: Siddhesh Poyarekar <siddhesh at redhat dot com>, Josh Boyer <jwboyer at fedoraproject dot org>, Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>, libc-alpha <libc-alpha at sourceware dot org>, Kyle McMartin <kmcmarti at redhat dot com>
- Date: Sat, 27 Sep 2014 01:38:57 -0400
- Subject: Re: Intel microcode update and glibc HLE
- Authentication-results: sourceware.org; auth=none
- References: <20140926180900 dot GW1716 at spoyarek dot pnq dot redhat dot com> <CA+5PVA5MVA+ZoLBObWgkmsi1JTj6SkFL+q6OnTLALxm2PnJ6Qw at mail dot gmail dot com> <20140926185440 dot GX1716 at spoyarek dot pnq dot redhat dot com> <542646B5 dot 6050103 at redhat dot com> <CAAHN_R0efpN7Df43agsTemdd-Hktid6s_5opO2FUPz+Na7xvrA at mail dot gmail dot com>
On 09/27/2014 01:14 AM, Siddhesh Poyarekar wrote:
> On 27 September 2014 10:40, Carlos O'Donell <email@example.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.
>> 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