From: Paolo Bonzini <pbonzini@redhat.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [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 [thread overview]
Message-ID: <55ABE196.6000201@redhat.com> (raw)
In-Reply-To: <1437307890.28088.108.camel@kernel.crashing.org>
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).
next prev parent reply other threads:[~2015-07-19 17:42 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-18 22:20 [Qemu-devel] [RFC PATCH 1/4] ppc: Remove MMU_MODEn_SUFFIX definitions Benjamin Herrenschmidt
2015-07-18 22:20 ` [Qemu-devel] [RFC PATCH 2/4] tlb: Add "ifetch" argument to cpu_mmu_index() Benjamin Herrenschmidt
2015-07-18 22:20 ` [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts Benjamin Herrenschmidt
2015-07-19 11:56 ` Paolo Bonzini
2015-07-19 12:11 ` Benjamin Herrenschmidt
2015-07-19 17:42 ` Paolo Bonzini [this message]
2015-07-19 21:51 ` Benjamin Herrenschmidt
2015-07-19 23:01 ` Aurelien Jarno
2015-07-19 23:33 ` Benjamin Herrenschmidt
2015-07-20 7:11 ` Aurelien Jarno
2015-07-20 8:12 ` Benjamin Herrenschmidt
2015-07-18 22:20 ` [Qemu-devel] [RFC PATCH 4/4] ppc: Do some batching of TCG tlb flushes Benjamin Herrenschmidt
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