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From: "Jan Beulich" <JBeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Tim Deegan <tim@xen.org>, Ian Jackson <Ian.Jackson@eu.citrix.com>,
	Julien Grall <julien.grall@arm.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: Ping: [PATCH 1/2] core-parking: interact with runtime SMT-disabling
Date: Mon, 27 May 2019 03:36:45 -0600	[thread overview]
Message-ID: <5CEBAFAD0200007800232B9A@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <5CB0796A0200007800226DDA@prv1-mh.provo.novell.com>

>>> On 12.04.19 at 13:41,  wrote:
>>>> On 11.04.19 at 21:06, <andrew.cooper3@citrix.com> wrote:
> > On 11/04/2019 13:45, Jan Beulich wrote:
> >> When disabling SMT at runtime, secondary threads should no longer be
> >> candidates for bringing back up in response to _PUD ACPI events. Purge
> >> them from the tracking array.
> >>
> >> Doing so involves adding locking to guard accounting data in the core
> >> parking code. While adding the declaration for the lock take the liberty
> >> to drop two unnecessary forward function declarations.
> >>
> >> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> > 
> > I can certainly appreciate these arguments, but surely the converse is
> > true.  When SMT-enable is used, the newly-onlined threads are now
> > eligible to be parked.
> 
> And nothing will keep them from getting parked.
> 
> > At the moment, this looks asymetric.
> 
> It does, but that's a result of core_parking.c only recording CPUs
> it has parked, not ones it could park.

Did my responses address your concerns?

Jan



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Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

WARNING: multiple messages have this Message-ID (diff)
From: "Jan Beulich" <JBeulich@suse.com>
To: "Andrew Cooper" <andrew.cooper3@citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Tim Deegan <tim@xen.org>, Ian Jackson <Ian.Jackson@eu.citrix.com>,
	Julien Grall <julien.grall@arm.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: [Xen-devel] Ping: [PATCH 1/2] core-parking: interact with runtime SMT-disabling
Date: Mon, 27 May 2019 03:36:45 -0600	[thread overview]
Message-ID: <5CEBAFAD0200007800232B9A@prv1-mh.provo.novell.com> (raw)
Message-ID: <20190527093645.Y-RXXMRpp2r98mf_c-K8NjiWvBzQds2FP6FuFHCGPB8@z> (raw)
In-Reply-To: <5CB0796A0200007800226DDA@prv1-mh.provo.novell.com>

>>> On 12.04.19 at 13:41,  wrote:
>>>> On 11.04.19 at 21:06, <andrew.cooper3@citrix.com> wrote:
> > On 11/04/2019 13:45, Jan Beulich wrote:
> >> When disabling SMT at runtime, secondary threads should no longer be
> >> candidates for bringing back up in response to _PUD ACPI events. Purge
> >> them from the tracking array.
> >>
> >> Doing so involves adding locking to guard accounting data in the core
> >> parking code. While adding the declaration for the lock take the liberty
> >> to drop two unnecessary forward function declarations.
> >>
> >> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> > 
> > I can certainly appreciate these arguments, but surely the converse is
> > true.  When SMT-enable is used, the newly-onlined threads are now
> > eligible to be parked.
> 
> And nothing will keep them from getting parked.
> 
> > At the moment, this looks asymetric.
> 
> It does, but that's a result of core_parking.c only recording CPUs
> it has parked, not ones it could park.

Did my responses address your concerns?

Jan



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

  reply	other threads:[~2019-05-27  9:36 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-11 12:04 [PATCH 0/2] core-parking: SMT-disable and section adjustments Jan Beulich
2019-04-11 12:04 ` [Xen-devel] " Jan Beulich
2019-04-11 12:45 ` [PATCH 1/2] core-parking: interact with runtime SMT-disabling Jan Beulich
2019-04-11 12:45   ` [Xen-devel] " Jan Beulich
2019-04-11 19:06   ` Andrew Cooper
2019-04-11 19:06     ` [Xen-devel] " Andrew Cooper
2019-04-12 11:41     ` Jan Beulich
2019-04-12 11:41       ` [Xen-devel] " Jan Beulich
2019-05-27  9:36       ` Jan Beulich [this message]
2019-05-27  9:36         ` [Xen-devel] Ping: " Jan Beulich
2019-04-24 11:51   ` Julien Grall
2019-04-24 11:51     ` [Xen-devel] " Julien Grall
2019-04-25 10:20     ` Jan Beulich
2019-04-25 10:20       ` [Xen-devel] " Jan Beulich
2019-04-11 12:45 ` [PATCH 2/2] core-parking: adjust data/code placement Jan Beulich
2019-04-11 12:45   ` [Xen-devel] " Jan Beulich
2019-04-11 19:01   ` Andrew Cooper
2019-04-11 19:01     ` [Xen-devel] " Andrew Cooper

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