Messages in this thread | | | Date | Tue, 27 Mar 2012 17:56:16 +0100 | From | Stefano Stabellini <> | Subject | Re: [PATCH 1/2] xen: enter/exit lazy_mmu_mode around m2p_override calls |
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On Tue, 27 Mar 2012, Konrad Rzeszutek Wilk wrote: > On Tue, Mar 27, 2012 at 02:52:43PM +0100, Stefano Stabellini wrote: > > This patch is a significant performance improvement for the > > How much? 10%? 90%?
I think you are overestimating the meaning of "significant" :)
It is about 6% using grant_table and 2% using blkback.
> > m2p_override. > > Can you explain what those calls do in the git commit description please?
Right, I have been way too concise.
Each m2p_add/remove_override call issues a MULTI_grant_table_op and a __flush_tlb_single if kmap_op != NULL. Batching all the calls together is a great performance benefit because it means issuing one hypercall total rather than two hypercall per page.
I'll resend with a proper commit message.
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