Messages in this thread | | | Date | Tue, 28 Jan 2014 07:42:02 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v3 0/4] Intel MPX support |
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* Ren Qiaowei <qiaowei.ren@intel.com> wrote:
> >> MPX kernel code, namely this patchset, has mainly the 2 > >> responsibilities: provide handlers for bounds faults (#BR), and > >> manage bounds memory. > > > > AFAICS the kernel side implementation causes no runtime overhead > > for non-MPX workloads, and also causes no runtime overhead for > > non-MPX hardware, right? > > Yes.
Actually, I think that's not entirely true.
For example if within the same mm there's a lot of non-MPX threads and an MPX thread, then the MMU notifier will be called for MMU operations of every non-MPX thread as well!
So MPX state of a thread will slow down all the other non-MPX threads as well.
The statement is only true for non-MPX tasks that have their separate mm's that does not have a single MPX thread.
Thanks,
Ingo
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