On 2011-02-16 11:27, Paolo Bonzini wrote: > On 02/16/2011 11:04 AM, Jan Kiszka wrote: >> On 2011-02-16 10:57, Paolo Bonzini wrote: >>> On 02/16/2011 10:46 AM, Jan Kiszka wrote: >>>> What should this be good for? The iothread already kicks the vcpu if it >>>> wants to acquire the contended global mutex. >>> >>> Assuming the VCPU is in the timedwait that Marcelo changed, the global >>> mutex is free and the iothread will not kick the VCPU. >> >> Then why should it kick it at all? > > To make it notice something changed in all_cpu_threads_idle---but that's > wrong, it should have been kicked in cpu_interrupt. > >> If we change the halt condition, we should not kick the vcpus but only >> signal the condition variable. Actually, I've a patch queued that skips >> pointless qemu_thread_signal in qemu_cpu_kick for TCG. > > Yes, I was kicking just because that's the wrapper that is used to > signal the condition variable---just like I was kicking in my patches to > eliminate timedwait. > >>> So, perhaps the correct fix is to kick the cpu in cpu_interrupt, and all >>> I wrote about timeouts and timers is wrong. My patch would band-aid it. >> >> That's my strong suspect. We really need to understand what goes wrong. > > I agree on both counts. >
FWIW, I've rebased most of your patches on top of my outstanding ones and pushed them to git://git.kiszka.org/qemu-kvm.git queues/kvm-upstream Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
