From: Cornelia Huck <cohuck@redhat.com>
To: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: qemu-ppc@nongnu.org, qemu-arm@nongnu.org, qemu-s390x@nongnu.org,
qemu-devel@nongnu.org,
"David Gibson" <david@gibson.dropbear.id.au>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Richard Henderson" <rth@twiddle.net>,
"Peter Maydell" <peter.maydell@linaro.org>,
"Aleksandar Markovic" <aleksandar.qemu.devel@gmail.com>,
"Aurelien Jarno" <aurelien@aurel32.net>,
"Jiaxun Yang" <jiaxun.yang@flygoat.com>,
"Aleksandar Rikalo" <aleksandar.rikalo@syrmia.com>,
"Mark Cave-Ayland" <mark.cave-ayland@ilande.co.uk>,
"Artyom Tarasenko" <atar4qemu@gmail.com>,
"Thomas Huth" <thuth@redhat.com>,
"David Hildenbrand" <david@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Greg Kurz" <groug@kaod.org>
Subject: Re: [RFC PATCH v3 8/8] target/s390x: Use start-powered-off CPUState property
Date: Thu, 30 Jul 2020 11:45:41 +0200 [thread overview]
Message-ID: <20200730114541.4dbdd15e.cohuck@redhat.com> (raw)
In-Reply-To: <87a6zjuoru.fsf@morokweng.localdomain>
On Tue, 28 Jul 2020 21:51:33 -0300
Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
> Hi,
>
> Cornelia Huck <cohuck@redhat.com> writes:
>
> > On Wed, 22 Jul 2020 23:56:57 -0300
> > Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
> >
> >> Instead of setting CPUState::halted to 1 in s390_cpu_initfn(), use the
> >> start-powered-off property which makes cpu_common_reset() initialize it
> >> to 1 in common code.
> >>
> >> Note that this changes behavior by setting cs->halted to 1 on reset, which
> >> didn't happen before.
> >
> > I think that should be fine, as we change the cpu state to STOPPED in
> > the reset function, which sets halted to 1.
>
> Nice, thanks for checking.
>
> >>
> >> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> >> ---
> >> target/s390x/cpu.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> NB: I was only able to test that this patch builds. I wasn't able to
> >> run it.
> >
> > No noticeable difference under kvm, but running under tcg seems a bit
> > more sluggish than usual, and I saw some pausing on reboot (after the
> > bios handover to the kernel). Not sure if it were just flukes on my
> > laptop, would appreciate if someone else could give it a go.
Experimented a bit with it again. There's a pause when switching from
the bios to the kernel (after the load reset normal has been done, I
guess), which is always there, but seems to get more noticeable with
this patch (varying wildly, but seems longer on average.) Hard to pin
down, and I don't really see a reason why that should happen, as we
should end up with halted == 1 in any case. Might still be a fluke,
even though I see it both on my laptop and on an LPAR (when running
under tcg; not seen under kvm, which is much faster anyway.)
>
> I tried today setting up a TCG guest, but didn't have success yet.
> Will try some more tomorrow.
>
I'm also looking a bit at the other s390 folks :)
WARNING: multiple messages have this Message-ID (diff)
From: Cornelia Huck <cohuck@redhat.com>
To: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Aleksandar Rikalo" <aleksandar.rikalo@syrmia.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Aleksandar Markovic" <aleksandar.qemu.devel@gmail.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"David Hildenbrand" <david@redhat.com>,
"Mark Cave-Ayland" <mark.cave-ayland@ilande.co.uk>,
qemu-devel@nongnu.org, "Greg Kurz" <groug@kaod.org>,
qemu-s390x@nongnu.org, qemu-arm@nongnu.org, qemu-ppc@nongnu.org,
"Artyom Tarasenko" <atar4qemu@gmail.com>,
"Thomas Huth" <thuth@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Richard Henderson" <rth@twiddle.net>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Aurelien Jarno" <aurelien@aurel32.net>,
"David Gibson" <david@gibson.dropbear.id.au>
Subject: Re: [RFC PATCH v3 8/8] target/s390x: Use start-powered-off CPUState property
Date: Thu, 30 Jul 2020 11:45:41 +0200 [thread overview]
Message-ID: <20200730114541.4dbdd15e.cohuck@redhat.com> (raw)
In-Reply-To: <87a6zjuoru.fsf@morokweng.localdomain>
On Tue, 28 Jul 2020 21:51:33 -0300
Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
> Hi,
>
> Cornelia Huck <cohuck@redhat.com> writes:
>
> > On Wed, 22 Jul 2020 23:56:57 -0300
> > Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
> >
> >> Instead of setting CPUState::halted to 1 in s390_cpu_initfn(), use the
> >> start-powered-off property which makes cpu_common_reset() initialize it
> >> to 1 in common code.
> >>
> >> Note that this changes behavior by setting cs->halted to 1 on reset, which
> >> didn't happen before.
> >
> > I think that should be fine, as we change the cpu state to STOPPED in
> > the reset function, which sets halted to 1.
>
> Nice, thanks for checking.
>
> >>
> >> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> >> ---
> >> target/s390x/cpu.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> NB: I was only able to test that this patch builds. I wasn't able to
> >> run it.
> >
> > No noticeable difference under kvm, but running under tcg seems a bit
> > more sluggish than usual, and I saw some pausing on reboot (after the
> > bios handover to the kernel). Not sure if it were just flukes on my
> > laptop, would appreciate if someone else could give it a go.
Experimented a bit with it again. There's a pause when switching from
the bios to the kernel (after the load reset normal has been done, I
guess), which is always there, but seems to get more noticeable with
this patch (varying wildly, but seems longer on average.) Hard to pin
down, and I don't really see a reason why that should happen, as we
should end up with halted == 1 in any case. Might still be a fluke,
even though I see it both on my laptop and on an LPAR (when running
under tcg; not seen under kvm, which is much faster anyway.)
>
> I tried today setting up a TCG guest, but didn't have success yet.
> Will try some more tomorrow.
>
I'm also looking a bit at the other s390 folks :)
next prev parent reply other threads:[~2020-07-30 9:45 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-23 2:56 [PATCH v3 0/8] Generalize start-powered-off property from ARM Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 2:56 ` [PATCH v3 1/8] target/arm: Move start-powered-off property to generic CPUState Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 3:06 ` David Gibson
2020-07-23 3:06 ` David Gibson
2020-07-23 3:33 ` Thiago Jung Bauermann
2020-07-23 3:33 ` Thiago Jung Bauermann
2020-07-27 12:36 ` Greg Kurz
2020-07-27 12:36 ` Greg Kurz
2020-07-28 23:00 ` Thiago Jung Bauermann
2020-07-28 23:00 ` Thiago Jung Bauermann
2020-07-23 2:56 ` [PATCH v3 2/8] target/arm: Move setting of CPU halted state to generic code Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 3:06 ` David Gibson
2020-07-23 3:06 ` David Gibson
2020-07-27 12:39 ` Greg Kurz
2020-07-27 12:39 ` Greg Kurz
2020-07-23 2:56 ` [PATCH v3 3/8] ppc/spapr: Use start-powered-off CPUState property Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 3:06 ` David Gibson
2020-07-23 3:06 ` David Gibson
2020-07-27 13:28 ` Greg Kurz
2020-07-27 13:28 ` Greg Kurz
2020-07-28 23:03 ` Thiago Jung Bauermann
2020-07-28 23:03 ` Thiago Jung Bauermann
2020-07-27 14:25 ` Philippe Mathieu-Daudé
2020-07-27 14:25 ` Philippe Mathieu-Daudé
2020-07-23 2:56 ` [PATCH v3 4/8] ppc/e500: " Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 3:07 ` David Gibson
2020-07-23 3:07 ` David Gibson
2020-07-23 2:56 ` [PATCH v3 5/8] mips/cps: " Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 3:07 ` David Gibson
2020-07-23 3:07 ` David Gibson
2020-07-23 2:56 ` [PATCH v3 6/8] sparc/sun4m: Remove main_cpu_reset() Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 3:08 ` David Gibson
2020-07-23 3:08 ` David Gibson
2020-07-23 2:56 ` [PATCH v3 7/8] sparc/sun4m: Use start-powered-off CPUState property Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-23 3:08 ` David Gibson
2020-07-23 3:08 ` David Gibson
2020-07-27 14:15 ` Philippe Mathieu-Daudé
2020-07-27 14:15 ` Philippe Mathieu-Daudé
2020-07-23 2:56 ` [RFC PATCH v3 8/8] target/s390x: " Thiago Jung Bauermann
2020-07-23 2:56 ` Thiago Jung Bauermann
2020-07-27 12:43 ` Cornelia Huck
2020-07-27 12:43 ` Cornelia Huck
2020-07-29 0:51 ` Thiago Jung Bauermann
2020-07-29 0:51 ` Thiago Jung Bauermann
2020-07-30 9:45 ` Cornelia Huck [this message]
2020-07-30 9:45 ` Cornelia Huck
2020-08-11 11:04 ` Cornelia Huck
2020-08-11 11:04 ` Cornelia Huck
2020-08-13 1:25 ` Thiago Jung Bauermann
2020-08-13 1:25 ` Thiago Jung Bauermann
2020-07-29 0:56 ` [PATCH v3 0/8] Generalize start-powered-off property from ARM Thiago Jung Bauermann
2020-07-29 0:56 ` Thiago Jung Bauermann
2020-07-30 0:59 ` David Gibson
2020-07-30 0:59 ` David Gibson
2020-07-30 11:05 ` Philippe Mathieu-Daudé
2020-07-30 15:04 ` Thiago Jung Bauermann
2020-07-30 15:04 ` Thiago Jung Bauermann
2020-08-05 17:01 ` Thiago Jung Bauermann
2020-08-05 17:01 ` Thiago Jung Bauermann
2020-08-05 19:04 ` Peter Maydell
2020-08-05 20:22 ` Thiago Jung Bauermann
2020-08-05 20:22 ` Thiago Jung Bauermann
2020-08-06 5:13 ` David Gibson
2020-08-06 5:13 ` David Gibson
2020-08-06 9:17 ` Peter Maydell
2020-08-06 9:17 ` Peter Maydell
2020-07-30 15:47 ` Peter Maydell
2020-07-30 15:47 ` Peter Maydell
2020-08-17 4:47 ` David Gibson
2020-08-17 4:47 ` David Gibson
2020-08-17 5:24 ` Philippe Mathieu-Daudé
2020-08-17 5:24 ` Philippe Mathieu-Daudé
2020-08-17 5:43 ` David Gibson
2020-08-17 5:43 ` David Gibson
2020-08-18 1:43 ` Thiago Jung Bauermann
2020-08-18 1:43 ` Thiago Jung Bauermann
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