From: Paul Mackerras <paulus@samba.org>
To: Alexander Graf <agraf@suse.de>
Cc: linuxppc-dev@ozlabs.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH 13/17] KVM: PPC: Allow book3s_hv guests to use SMT processor modes
Date: Mon, 16 Apr 2012 22:13:15 +1000 [thread overview]
Message-ID: <20120416121315.GA26814@bloggs.ozlabs.ibm.com> (raw)
In-Reply-To: <056AF183-5218-457B-9501-B0FF5ED455E9@suse.de>
On Mon, Apr 16, 2012 at 11:45:44AM +0200, Alexander Graf wrote:
> While trying to trace down why some BookE systems were only able to
> do as many guest vcpus as there were host cpus available, we
> stumbled over this one. Is there any limitation on book3s_hv that
> would limit the available vcpus to configured host vcpus? Or could
> we just make this a static define like on x86?
There is no limitation. I did it like that so that we would be able
to have a large number of vcpus on kernels configured for large
systems, while not using up large amounts of memory if the kernel is
configured for a small system. The memory consumption is 8 bytes per
vcore in each struct kvm if book3s_hv is configured.
We can make it a fixed constant if you like, but then the question is
how do you choose that constant so as to allow us to have many vcpus
on large systems but still not waste too much memory on small systems.
Or it could be max(N, NR_CPUS) for a suitable N (e.g. 16 or 32).
Paul.
next prev parent reply other threads:[~2012-04-16 12:13 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-29 10:15 [PATCH 0/17] Hypervisor-mode KVM on POWER7 and PPC970 Paul Mackerras
2011-06-29 10:16 ` [PATCH 01/17] KVM: PPC: Fix machine checks on 32-bit Book3S Paul Mackerras
2011-07-01 10:08 ` Alexander Graf
2011-06-29 10:17 ` [PATCH 02/17] KVM: PPC: Move fields between struct kvm_vcpu_arch and kvmppc_vcpu_book3s Paul Mackerras
2011-06-29 10:17 ` [PATCH 03/17] KVM: PPC: Split out code from book3s.c into book3s_pr.c Paul Mackerras
2011-06-29 10:18 ` [PATCH 04/17] powerpc, KVM: Rework KVM checks in first-level interrupt handlers Paul Mackerras
2011-06-29 10:18 ` [PATCH 05/17] KVM: PPC: Deliver program interrupts right away instead of queueing them Paul Mackerras
2011-07-01 11:47 ` Alexander Graf
2011-06-29 10:19 ` [PATCH 06/17] KVM: PPC: Pass init/destroy vm and prepare/commit memory region ops down Paul Mackerras
2011-06-29 10:19 ` [PATCH 07/17] KVM: PPC: Move guest enter/exit down into subarch-specific code Paul Mackerras
2011-06-29 10:20 ` [PATCH 08/17] powerpc: Set up LPCR for running guest partitions Paul Mackerras
2011-06-29 10:20 ` [PATCH 09/17] KVM: PPC: Split host-state fields out of kvmppc_book3s_shadow_vcpu Paul Mackerras
2011-06-29 10:21 ` [PATCH 10/17] KVM: PPC: Add support for Book3S processors in hypervisor mode Paul Mackerras
2011-07-01 18:37 ` Dave Hansen
2011-07-01 19:12 ` Alexander Graf
2011-07-04 11:51 ` Paul Mackerras
2011-06-29 10:22 ` [PATCH 11/17] KVM: PPC: Handle some PAPR hcalls in the kernel Paul Mackerras
2011-06-29 10:22 ` [PATCH 12/17] KVM: PPC: Accelerate H_PUT_TCE by implementing it in real mode Paul Mackerras
2011-06-29 10:23 ` [PATCH 13/17] KVM: PPC: Allow book3s_hv guests to use SMT processor modes Paul Mackerras
2012-04-16 9:45 ` Alexander Graf
2012-04-16 12:13 ` Paul Mackerras [this message]
2012-04-16 13:01 ` Alexander Graf
2011-06-29 10:25 ` [PATCH 14/17] KVM: PPC: Allocate RMAs (Real Mode Areas) at boot for use by guests Paul Mackerras
2011-06-29 10:26 ` [PATCH 15/17] powerpc, KVM: Split HVMODE_206 cpu feature bit into separate HV and architecture bits Paul Mackerras
2011-06-29 10:40 ` [PATCH 16/17] KVM: PPC: book3s_hv: Add support for PPC970-family processors Paul Mackerras
2011-06-29 10:41 ` [RFC PATCH 17/17] KVM: PPC: Add an ioctl for userspace to select which platform to emulate Paul Mackerras
2011-06-29 11:53 ` Josh Boyer
2011-06-29 11:56 ` Alexander Graf
2011-06-29 11:58 ` Josh Boyer
2011-06-30 8:34 ` Avi Kivity
2011-06-30 15:04 ` Alexander Graf
2011-06-30 15:16 ` Avi Kivity
2011-06-30 15:22 ` Alexander Graf
2011-06-30 16:00 ` Avi Kivity
2011-06-30 16:33 ` Alexander Graf
2011-07-03 8:15 ` Avi Kivity
2011-07-03 8:34 ` Alexander Graf
2011-07-03 8:56 ` Avi Kivity
2011-07-03 9:00 ` Alexander Graf
2011-07-03 9:05 ` Avi Kivity
2011-07-03 9:09 ` Alexander Graf
2011-07-03 9:12 ` Avi Kivity
2011-07-04 10:59 ` Alexander Graf
2011-07-04 11:22 ` Avi Kivity
2011-07-04 11:36 ` Alexander Graf
2011-07-04 11:37 ` Avi Kivity
2011-07-04 11:41 ` Alexander Graf
2011-06-30 23:13 ` Benjamin Herrenschmidt
2011-07-01 10:09 ` Paul Mackerras
2011-07-01 10:23 ` Alexander Graf
2011-07-01 18:24 ` [PATCH 0/17] Hypervisor-mode KVM on POWER7 and PPC970 Alexander Graf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120416121315.GA26814@bloggs.ozlabs.ibm.com \
--to=paulus@samba.org \
--cc=agraf@suse.de \
--cc=kvm-ppc@vger.kernel.org \
--cc=kvm@vger.kernel.org \
--cc=linuxppc-dev@ozlabs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).