Messages in this thread | | | Date | Wed, 26 Oct 2016 13:24:27 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v6 5/9] x86/sysctl: Add sysctl for ITMT scheduling feature |
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On Wed, 26 Oct 2016, Peter Zijlstra wrote: > On Wed, Oct 26, 2016 at 12:49:36PM +0200, Thomas Gleixner wrote: > > > > + /* > > > + * ITMT capability automatically enables ITMT > > > + * scheduling for small systems (single node). > > > + */ > > > + if (topology_num_packages() == 1) > > > + sysctl_sched_itmt_enabled = 1; > > > > I really hate this. This is policy and the kernel should not impose > > policy. Why would I like to have this enforced on my single socket XEON > > server? > > So this really wants to be enabled by default; otherwise nobody will use > this, and it really does help single threaded workloads.
Fair enough. Then this wants to be documented.
> There were reservations on the multi-socket case of ITMT, maybe it would > help to spell those out in great detail here. That is, have the comment > explain the policy instead of simply stating what the code does (which > is always bad comment policy, you can read the code just fine).
What is the objection for multi sockets? If it improves the behaviour then why would this be a bad thing for multi sockets?
Thanks,
tglx
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