From: Wei Liu <wei.liu2@citrix.com>
To: Joao Martins <joao.m.martins@oracle.com>
Cc: Wei Liu <wei.liu2@citrix.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
Ian Campbell <ian.campbell@citrix.com>,
xen-devel@lists.xen.org
Subject: Re: [PATCH RFC 5/8] libxl: introduce smt field
Date: Thu, 25 Feb 2016 16:29:06 +0000 [thread overview]
Message-ID: <20160225162906.GI5694@citrix.com> (raw)
In-Reply-To: <1456174934-22973-6-git-send-email-joao.m.martins@oracle.com>
On Mon, Feb 22, 2016 at 09:02:11PM +0000, Joao Martins wrote:
> By setting it to true, it enables the vcpus set by the guest
> to be seen as a SMT-enabled topology. It uses then
> libxl__cpuid_set_topology() to change the cpuid accordingly.
> This setting is made *before* the cpuid is set so that
> any changes could be overwritten. The number of SMT threads
> are the ones supported by the host. And for that it adds
> another helper routine libxl__count_threads_per_core to fetch
> it.
>
> This feature is useful in HT-enabled hosts so that hard
> pinned domains can see the right topology (i.e. SMT cores exposed
> as SMT cores) which in return would lead guest scheduler making
> better decisions.
>
I think we need more sophisticated configuration options then just a
bool. If we're doing this, there is no reason why we shouldn't allow
administrator to set arbitrary topology for the guest.
Wei.
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next prev parent reply other threads:[~2016-02-25 16:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-22 21:02 [PATCH RFC 0/8] x86/hvm, libxl: HVM SMT topology support Joao Martins
2016-02-22 21:02 ` [PATCH RFC 1/8] x86/hvm: set initial apicid to vcpu_id Joao Martins
2016-02-25 17:03 ` Jan Beulich
2016-03-02 18:49 ` Joao Martins
2016-02-22 21:02 ` [PATCH RFC 2/8] libxl: remove whitespace on libxl_types.idl Joao Martins
2016-02-25 16:28 ` Wei Liu
2016-03-02 19:14 ` Joao Martins
2016-02-22 21:02 ` [PATCH RFC 3/8] libxl: cpuid: add cache core count support Joao Martins
2016-02-22 21:02 ` [PATCH RFC 4/8] libxl: cpuid: add guest topology support Joao Martins
2016-02-25 16:29 ` Wei Liu
2016-03-02 19:14 ` Joao Martins
2016-02-22 21:02 ` [PATCH RFC 5/8] libxl: introduce smt field Joao Martins
2016-02-25 16:29 ` Wei Liu [this message]
2016-02-22 21:02 ` [PATCH RFC 6/8] xl: introduce smt option Joao Martins
2016-02-22 21:02 ` [PATCH RFC 7/8] libxl: introduce topology fields Joao Martins
2016-02-25 16:29 ` Wei Liu
2016-03-02 19:16 ` Joao Martins
2016-02-22 21:02 ` [PATCH RFC 8/8] xl: introduce topology options Joao Martins
2016-02-25 17:21 ` [PATCH RFC 0/8] x86/hvm, libxl: HVM SMT topology support Andrew Cooper
2016-02-26 15:03 ` Dario Faggioli
2016-02-26 15:27 ` Konrad Rzeszutek Wilk
2016-02-26 15:42 ` Dario Faggioli
2016-02-26 15:48 ` Andrew Cooper
2016-03-02 19:18 ` Joao Martins
2016-03-02 20:03 ` Andrew Cooper
2016-03-03 9:52 ` Joao Martins
2016-03-03 10:24 ` Andrew Cooper
2016-03-03 12:23 ` Joao Martins
2016-03-03 12:48 ` Andrew Cooper
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