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Thu, 30 Jul 2020 09:45:43 +0000 (UTC) Date: Thu, 30 Jul 2020 11:45:41 +0200 From: Cornelia Huck To: Thiago Jung Bauermann Subject: Re: [RFC PATCH v3 8/8] target/s390x: Use start-powered-off CPUState property Message-ID: <20200730114541.4dbdd15e.cohuck@redhat.com> In-Reply-To: <87a6zjuoru.fsf@morokweng.localdomain> References: <20200723025657.644724-1-bauerman@linux.ibm.com> <20200723025657.644724-9-bauerman@linux.ibm.com> <20200727144350.47abd7e7.cohuck@redhat.com> <87a6zjuoru.fsf@morokweng.localdomain> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=cohuck@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/29 23:51:30 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Aleksandar Rikalo , Eduardo Habkost , Aleksandar Markovic , Alex =?UTF-8?B?QmVubsOpZQ==?= , David Hildenbrand , Mark Cave-Ayland , qemu-devel@nongnu.org, Greg Kurz , qemu-s390x@nongnu.org, qemu-arm@nongnu.org, qemu-ppc@nongnu.org, Artyom Tarasenko , Thomas Huth , Paolo Bonzini , Richard Henderson , Philippe =?UTF-8?B?TWF0aGlldS1EYXVkw6k=?= , Aurelien Jarno , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 28 Jul 2020 21:51:33 -0300 Thiago Jung Bauermann wrote: > Hi, > > Cornelia Huck writes: > > > On Wed, 22 Jul 2020 23:56:57 -0300 > > Thiago Jung Bauermann 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 > >> --- > >> 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 :)