Cornelia Huck <coh...@redhat.com> writes:
> On Thu, 30 Jul 2020 11:45:41 +0200 > Cornelia Huck <coh...@redhat.com> wrote: > >> On Tue, 28 Jul 2020 21:51:33 -0300 >> Thiago Jung Bauermann <bauer...@linux.ibm.com> wrote: >> >> > Hi, >> > >> > Cornelia Huck <coh...@redhat.com> writes: >> > >> > > On Wed, 22 Jul 2020 23:56:57 -0300 >> > > Thiago Jung Bauermann <bauer...@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 <bauer...@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.) > > Tried again, the pause now seems comparable to the pause prior to this > series. Might depend on the phase of the moon. > > I ran kvm unit tests on it, and it looks good. So, I'm reasonable > confident that this is fine, really just seems to be a fluke. > > Acked-by: Cornelia Huck <coh...@redhat.com> Ah, that's a relief. Thank you very much for looking into this! -- Thiago Jung Bauermann IBM Linux Technology Center