From: Andrew Cooper <andrew.cooper3@citrix.com> To: Julien Grall <julien.grall@arm.com>, Dario Faggioli <dfaggioli@suse.com>, Andrii Anisov <andrii.anisov@gmail.com>, xen-devel@lists.xenproject.org Cc: "Juergen Gross" <jgross@suse.com>, "Stefano Stabellini" <sstabellini@kernel.org>, "Wei Liu" <wei.liu2@citrix.com>, "George Dunlap" <george.dunlap@citrix.com>, "Jan Beulich" <jbeulich@suse.com>, "Roger Pau Monné" <roger.pau@citrix.com> Subject: Re: [PATCH 2/2] xen: sched: we never get into context_switch() with prev==next Date: Fri, 26 Apr 2019 17:26:25 +0100 [thread overview] Message-ID: <04305f60-785d-cd21-1de4-9772f5bda198@citrix.com> (raw) In-Reply-To: <b0ab9ed7-135b-6240-a0e8-8200e478b6f8@arm.com> On 26/04/2019 17:22, Julien Grall wrote: > Hi Dario, > > On 26/04/2019 16:13, Dario Faggioli wrote: >> On Tue, 2019-04-23 at 12:13 +0300, Andrii Anisov wrote: >>> Hello Dario, >>> >>> On 20.04.19 18:24, Dario Faggioli wrote: >>>> In schedule(), if we pick, as the next vcpu to run (next) the same >>>> one >>>> that is running already (prev), we never get to call >>>> context_switch(). >>> >>> And what about `if ( prev != current )` in >>> arm/domain.c:schedule_tail() ? >>> >> You're suggesting that's redundant too, aren't you? >> >> From a quick look, it seems to me as well that it would be. I'm ok >> taking care of it, not sure if in this patch, or in another one. > > I thought Andrew already queued this patch? I did. > > Anyway, I think you are right. We can drop the check in > schedule_tail() as well. That should really be a separate patch, because it is ARM-specific scheduling behaviour. The same is not true on x86. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Cooper <andrew.cooper3@citrix.com> To: Julien Grall <julien.grall@arm.com>, Dario Faggioli <dfaggioli@suse.com>, Andrii Anisov <andrii.anisov@gmail.com>, <xen-devel@lists.xenproject.org> Cc: "Juergen Gross" <jgross@suse.com>, "Stefano Stabellini" <sstabellini@kernel.org>, "Wei Liu" <wei.liu2@citrix.com>, "George Dunlap" <george.dunlap@citrix.com>, "Jan Beulich" <jbeulich@suse.com>, "Roger Pau Monné" <roger.pau@citrix.com> Subject: Re: [Xen-devel] [PATCH 2/2] xen: sched: we never get into context_switch() with prev==next Date: Fri, 26 Apr 2019 17:26:25 +0100 [thread overview] Message-ID: <04305f60-785d-cd21-1de4-9772f5bda198@citrix.com> (raw) Message-ID: <20190426162625.OimJdzYENCHsWUHbJWjJIVbgJ7-vORhXRPbQFAxaoCA@z> (raw) In-Reply-To: <b0ab9ed7-135b-6240-a0e8-8200e478b6f8@arm.com> On 26/04/2019 17:22, Julien Grall wrote: > Hi Dario, > > On 26/04/2019 16:13, Dario Faggioli wrote: >> On Tue, 2019-04-23 at 12:13 +0300, Andrii Anisov wrote: >>> Hello Dario, >>> >>> On 20.04.19 18:24, Dario Faggioli wrote: >>>> In schedule(), if we pick, as the next vcpu to run (next) the same >>>> one >>>> that is running already (prev), we never get to call >>>> context_switch(). >>> >>> And what about `if ( prev != current )` in >>> arm/domain.c:schedule_tail() ? >>> >> You're suggesting that's redundant too, aren't you? >> >> From a quick look, it seems to me as well that it would be. I'm ok >> taking care of it, not sure if in this patch, or in another one. > > I thought Andrew already queued this patch? I did. > > Anyway, I think you are right. We can drop the check in > schedule_tail() as well. That should really be a separate patch, because it is ARM-specific scheduling behaviour. The same is not true on x86. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply other threads:[~2019-04-26 16:26 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-20 15:24 [PATCH 0/2] xen: sched/Credit2: small and trivial improvements Dario Faggioli 2019-04-20 15:24 ` [Xen-devel] " Dario Faggioli 2019-04-20 15:24 ` [PATCH 1/2] xen: credit2: avoid using cpumask_weight() in hot-paths Dario Faggioli 2019-04-20 15:24 ` [Xen-devel] " Dario Faggioli 2019-04-23 9:44 ` Andrew Cooper 2019-04-23 9:44 ` [Xen-devel] " Andrew Cooper 2019-04-26 13:01 ` Dario Faggioli 2019-04-26 13:01 ` [Xen-devel] " Dario Faggioli 2019-04-23 9:48 ` Andrii Anisov 2019-04-23 9:48 ` [Xen-devel] " Andrii Anisov 2019-04-20 15:24 ` [PATCH 2/2] xen: sched: we never get into context_switch() with prev==next Dario Faggioli 2019-04-20 15:24 ` [Xen-devel] " Dario Faggioli 2019-04-21 17:08 ` Julien Grall 2019-04-21 17:08 ` [Xen-devel] " Julien Grall 2019-04-23 9:13 ` Andrii Anisov 2019-04-23 9:13 ` [Xen-devel] " Andrii Anisov 2019-04-23 9:47 ` Andrew Cooper 2019-04-23 9:47 ` [Xen-devel] " Andrew Cooper 2019-04-23 10:33 ` Andrii Anisov 2019-04-23 10:33 ` [Xen-devel] " Andrii Anisov 2019-04-26 15:13 ` Dario Faggioli 2019-04-26 15:13 ` [Xen-devel] " Dario Faggioli 2019-04-26 16:22 ` Julien Grall 2019-04-26 16:22 ` [Xen-devel] " Julien Grall 2019-04-26 16:26 ` Andrew Cooper [this message] 2019-04-26 16:26 ` Andrew Cooper 2019-05-08 10:03 ` Andrii Anisov 2019-05-08 10:03 ` [Xen-devel] " Andrii Anisov 2019-04-23 9:50 ` George Dunlap 2019-04-23 9:50 ` [Xen-devel] " George Dunlap 2019-04-23 9:56 ` Juergen Gross 2019-04-23 9:56 ` [Xen-devel] " Juergen Gross 2019-04-26 12:58 ` Dario Faggioli 2019-04-26 12:58 ` [Xen-devel] " Dario Faggioli 2019-04-23 10:00 ` Andrew Cooper 2019-04-23 10:00 ` [Xen-devel] " Andrew Cooper
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