From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46519) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZGsc4-0007es-Iv for qemu-devel@nongnu.org; Sun, 19 Jul 2015 13:42:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZGsc1-0005GT-7H for qemu-devel@nongnu.org; Sun, 19 Jul 2015 13:42:56 -0400 Sender: Paolo Bonzini References: <1437258018-13982-1-git-send-email-benh@kernel.crashing.org> <1437258018-13982-3-git-send-email-benh@kernel.crashing.org> <55AB9068.8050202@redhat.com> <1437307890.28088.108.camel@kernel.crashing.org> From: Paolo Bonzini Message-ID: <55ABE196.6000201@redhat.com> Date: Sun, 19 Jul 2015 19:42:46 +0200 MIME-Version: 1.0 In-Reply-To: <1437307890.28088.108.camel@kernel.crashing.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Benjamin Herrenschmidt Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.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).