Re: Intel microcode update and glibc HLE

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

On Fri, Sep 26, 2014 at 03:19:34PM -0300, Adhemerval Zanella wrote:
> I am about to ping about my patches to add support of TLE on POWER8, and
> with this recent issue with HLE on Intel lead to an idea of creating
> a patch to enabled TLE conditionally using an environment variable.  The
> idea is to build GLIBC with TLE enabled, add the environment variable
> and let architecture work based on its value.
> 
> I know this maybe not the best solution in long term if we aim to enable
> TLE as default (we will need to either deprecate the env. var or change its
> semantics), but my idea is to let developers a way to evaluate either if
> TLE is safe and if it indeed gives the workload a performance boost.

We've thrown around the idea of using tunables (yes, that abstract
vapourware that we've mentioned before and never written code for.
some day...) for things like elision, so your idea matches with that
in principle.

Siddhesh

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