From: Paolo Bonzini <pbonzini@redhat.com>
To: jjherne@linux.vnet.ibm.com, afaerber@suse.de,
amit.shah@redhat.com, dgilbert@redhat.com,
borntraeger@de.ibm.com, quintela@redhat.com,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v4 1/5] cpu: Provide vcpu throttling interface
Date: Mon, 13 Jul 2015 17:14:32 +0200 [thread overview]
Message-ID: <55A3D5D8.7070902@redhat.com> (raw)
In-Reply-To: <55A3CEAF.6030504@linux.vnet.ibm.com>
On 13/07/2015 16:43, Jason J. Herne wrote:
>>>
>>> + CPU_FOREACH(cpu) {
>>> + async_run_on_cpu(cpu, cpu_throttle_thread, NULL);
>>> + }
>>> +
>>> + timer_mod(throttle_timer,
>>> qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) +
>>> + CPU_THROTTLE_TIMESLICE);
>>> +}
>>
>> This could cause callbacks to pile up I think. David, do you have any
>> idea how to fix it?
>
> I'm not sure how callbacks can pile up here. If the vcpus are running
> then their thread's will execute the callbacks. If they are not running
> then the use of QEMU_CLOCK_VIRTUAL_RT will prevent the callbacks from
> stacking because the timer is not running, right?
Couldn't the iothread starve the VCPUs? They need to take the iothread
lock in order to process the callbacks.
Paolo
next prev parent reply other threads:[~2015-07-13 15:14 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-02 16:36 [Qemu-devel] [PATCH v4 0/5] migration: Dynamic cpu throttling for auto-converge Jason J. Herne
2015-07-02 16:36 ` [Qemu-devel] [PATCH v4 1/5] cpu: Provide vcpu throttling interface Jason J. Herne
2015-07-02 16:43 ` Paolo Bonzini
2015-07-02 16:58 ` Dr. David Alan Gilbert
2015-07-13 14:43 ` Jason J. Herne
2015-07-13 15:14 ` Paolo Bonzini [this message]
2015-07-15 12:40 ` Jason J. Herne
2015-07-15 12:54 ` Paolo Bonzini
2015-07-16 14:21 ` Jason J. Herne
2015-07-23 9:59 ` Paolo Bonzini
2015-07-31 17:12 ` Jason J. Herne
2015-07-31 17:16 ` Paolo Bonzini
2015-07-31 17:42 ` Jason J. Herne
2015-07-31 18:11 ` Jason J. Herne
2015-08-01 9:40 ` Paolo Bonzini
2015-09-01 14:43 ` Jason J. Herne
2015-07-02 16:47 ` Andreas Färber
2015-07-02 16:36 ` [Qemu-devel] [PATCH v4 2/5] migration: Parameters for auto-converge cpu throttling Jason J. Herne
2015-07-02 16:36 ` [Qemu-devel] [PATCH v4 3/5] migration: Dynamic cpu throttling for auto-converge Jason J. Herne
2015-07-02 16:36 ` [Qemu-devel] [PATCH v4 4/5] qmp/hmp: Add throttle ratio to query-migrate and info migrate Jason J. Herne
2015-07-02 16:36 ` [Qemu-devel] [PATCH v4 5/5] migration: Disambiguate MAX_THROTTLE Jason J. Herne
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