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[Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHR
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2) |
Date: |
Wed, 16 Feb 2011 11:34:05 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
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
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD, (continued)
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD, Marcelo Tosatti, 2011/02/15
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD, Jan Kiszka, 2011/02/15
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD, Marcelo Tosatti, 2011/02/15
- [Qemu-devel] [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Marcelo Tosatti, 2011/02/15
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Jan Kiszka, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Paolo Bonzini, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Jan Kiszka, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Paolo Bonzini, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Jan Kiszka, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Paolo Bonzini, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2),
Jan Kiszka <=
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Paolo Bonzini, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Marcelo Tosatti, 2011/02/16
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Paolo Bonzini, 2011/02/17
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Paolo Bonzini, 2011/02/18
- [Qemu-devel] Re: [PATCH] fix halt emulation with icount and CONFIG_IOTHREAD (v2), Jan Kiszka, 2011/02/17