From: Hollis Blanchard <hollis_blanchard-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>
To: Liu Yu-B13201 <B13201-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
Cc: kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kvm-ppc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
agraf-l3A5Bk7waGM@public.gmane.org
Subject: Re: [PATCH 1/2] kvm/e500v2: Remove shadow tlb
Date: Thu, 09 Sep 2010 11:13:38 -0700 [thread overview]
Message-ID: <4C8923D2.5070308@mentor.com> (raw)
In-Reply-To: <A9833F0F7901024DA08417AA5A9887D91BF24A-bKEhWGtIRUJ4Lp7cDGe+DVjVikpgYyvb5NbjCUgZEJk@public.gmane.org>
On 09/09/2010 04:16 AM, Liu Yu-B13201 wrote:
> Yes, it's hard to resume TLB0. We only resume TLB1 in previous code.
> But TLB1 is even more smaller (13 free entries) than 440,
> So that it still has little possibility to get hit.
> thus the resumption is useless.
>
The only reason hits are unlikely in TLB1 is because you still don't
have large page support in the host. Once you have that, you can use
TLB1 for large guest mappings, and it will become extremely likely that
you get hits in TLB1. This is true even if the guest wants 256MB but the
host supports only e.g. 16MB large pages, and must split the guest
mapping into multiple large host pages.
When will you have hugetlbfs for e500? That's going to make such a
dramatic difference, I'm not sure it's worth investing time in
optimizing the MMU code until then.
Hollis Blanchard
Mentor Graphics, Embedded Systems Division
next prev parent reply other threads:[~2010-09-09 18:13 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-08 9:40 [PATCH 0/2] kvm/e500v2: MMU optimization Liu Yu
[not found] ` <1283938806-2981-1-git-send-email-yu.liu-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
2010-09-08 9:40 ` [PATCH 1/2] kvm/e500v2: Remove shadow tlb Liu Yu
2010-09-08 9:40 ` [PATCH 2/2] kvm/e500v2: mapping guest TLB1 to host TLB0 Liu Yu
[not found] ` <1283938806-2981-3-git-send-email-yu.liu-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
2010-09-09 23:24 ` Alexander Graf
[not found] ` <E759E1E3-7457-41B7-B36E-75FA42E107B1-l3A5Bk7waGM@public.gmane.org>
2010-09-15 9:29 ` Alexander Graf
2010-09-16 11:35 ` Liu Yu-B13201
[not found] ` <A9833F0F7901024DA08417AA5A9887D921DD39-bKEhWGtIRUJ4Lp7cDGe+DVjVikpgYyvb5NbjCUgZEJk@public.gmane.org>
2010-09-16 11:44 ` Alexander Graf
2010-09-17 8:47 ` Liu Yu-B13201
[not found] ` <A9833F0F7901024DA08417AA5A9887D921DE82-bKEhWGtIRUJ4Lp7cDGe+DVjVikpgYyvb5NbjCUgZEJk@public.gmane.org>
2010-09-17 10:19 ` Alexander Graf
2010-09-17 11:28 ` Liu Yu-B13201
[not found] ` <A9833F0F7901024DA08417AA5A9887D921DE99-bKEhWGtIRUJ4Lp7cDGe+DVjVikpgYyvb5NbjCUgZEJk@public.gmane.org>
2010-09-17 11:34 ` Alexander Graf
2010-09-17 12:33 ` Liu Yu-B13201
2010-09-17 12:34 ` Alexander Graf
[not found] ` <1283938806-2981-2-git-send-email-yu.liu-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
2010-09-08 16:06 ` [PATCH 1/2] kvm/e500v2: Remove shadow tlb Hollis Blanchard
2010-09-09 11:16 ` Liu Yu-B13201
[not found] ` <A9833F0F7901024DA08417AA5A9887D91BF24A-bKEhWGtIRUJ4Lp7cDGe+DVjVikpgYyvb5NbjCUgZEJk@public.gmane.org>
2010-09-09 18:13 ` Hollis Blanchard [this message]
[not found] ` <4C8923D2.5070308-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>
2010-09-09 23:26 ` Alexander Graf
[not found] ` <C1EBC75A-91B0-49D9-8AD5-571C6BAF22B7-l3A5Bk7waGM@public.gmane.org>
2010-09-09 23:39 ` Hollis Blanchard
2010-09-09 23:42 ` Alexander Graf
2010-09-08 16:07 ` [PATCH 0/2] kvm/e500v2: MMU optimization Hollis Blanchard
[not found] ` <4C87B4AB.7010009-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>
2010-09-09 11:03 ` Liu Yu-B13201
[not found] ` <A9833F0F7901024DA08417AA5A9887D91BF248-bKEhWGtIRUJ4Lp7cDGe+DVjVikpgYyvb5NbjCUgZEJk@public.gmane.org>
2010-09-09 16:23 ` Hollis Blanchard
2010-09-10 2:59 ` Liu Yu-B13201
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