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Re: [Qemu-ppc] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flu
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-ppc] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts |
Date: |
Sun, 19 Jul 2015 19:42:46 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 |
On 19/07/2015 14:11, Benjamin Herrenschmidt wrote:
> Ok, I assumed incorrectly that 8 was too much based on your changeset
> comment:
>
> <<
> At 8k per TLB (for 64-bit host or target), 8 or more modes
> make the TLBs bigger than 64k, and some RISC TCG backends do
> not like that. On the affected hosts, cut the TLB size in
> half---there is still a measurable speedup on PPC with the
> next patch.
> >>
>
> IE, you wrote "8 or more".
Indeed... at 8 the TLBs are exactly 64k.
Paolo
> I can easily fold back guest vs. HV into BookE, though we don't
> generally support BookE HV mode anyway in TCG so there's no big hurry in
> doing so (we need to add support for the shadow SPRs and a bunch of
> other things for that to work).
- [Qemu-ppc] [RFC PATCH 1/4] ppc: Remove MMU_MODEn_SUFFIX definitions, Benjamin Herrenschmidt, 2015/07/18
- [Qemu-ppc] [RFC PATCH 4/4] ppc: Do some batching of TCG tlb flushes, Benjamin Herrenschmidt, 2015/07/18
- [Qemu-ppc] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Benjamin Herrenschmidt, 2015/07/18
- Re: [Qemu-ppc] [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Aurelien Jarno, 2015/07/19
- Re: [Qemu-ppc] [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Benjamin Herrenschmidt, 2015/07/19
- Re: [Qemu-ppc] [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Aurelien Jarno, 2015/07/20
- Re: [Qemu-ppc] [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Benjamin Herrenschmidt, 2015/07/20
[Qemu-ppc] [RFC PATCH 2/4] tlb: Add "ifetch" argument to cpu_mmu_index(), Benjamin Herrenschmidt, 2015/07/18