From: Marcelo Tosatti <mtosatti@redhat.com>
To: Sheng Yang <sheng@linux.intel.com>
Cc: kvm@vger.kernel.org
Subject: Re: [patch 0/4] use smp_send_reschedule in vcpu_kick / assigned dev host intx race fix
Date: Wed, 29 Apr 2009 14:47:57 -0300 [thread overview]
Message-ID: <20090429174757.GA7379@amt.cnet> (raw)
In-Reply-To: <200904281508.47370.sheng@linux.intel.com>
On Tue, Apr 28, 2009 at 03:08:46PM +0800, Sheng Yang wrote:
> Ack all. This also solved one bug by my hand. Thanks!
>
> I observe one point: the performance of high workload interrupt(e.g. 10
> gigabyte oplin card) dropped dramatically with smp_send_reschedule() method...
> In one environment(the speed of oplin card also limited by cpu performance),
> Using smp_call_function_single() can get more than 1G bit/s stably(native got
> 1.2G), but smp_send_reschedule() can only got around 600M bit/s... And the
> rescheduling interrupt number is about 2000/second per cpu. And the interrupt
> rate is about tens of thousands per second for the device.
>
> Anyway, this method is more elegant and correct. Though there is still room
> for optimize - but of course, the correctness is first priority.
Are you using the compat code or a kvm.git kernel? Can you remove only the
last patch (the spinlock) to confirm its the cause of the slowdown?
next prev parent reply other threads:[~2009-04-29 18:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-27 21:07 [patch 0/4] use smp_send_reschedule in vcpu_kick / assigned dev host intx race fix mtosatti
2009-04-27 21:07 ` [patch 1/4] qemu: external module: smp_send_reschedule compat mtosatti
2009-05-07 13:28 ` Avi Kivity
2009-04-27 21:07 ` [patch 2/4] KVM: x86: wake up waitqueue before calling get_cpu() mtosatti
2009-04-27 21:07 ` [patch 3/4] KVM: use smp_send_reschedule in kvm_vcpu_kick mtosatti
2009-04-27 21:07 ` [patch 4/4] KVM: protect assigned dev workqueue, int handler and irq acker mtosatti
2009-04-28 7:08 ` [patch 0/4] use smp_send_reschedule in vcpu_kick / assigned dev host intx race fix Sheng Yang
2009-04-29 17:47 ` Marcelo Tosatti [this message]
2009-04-30 0:56 ` Sheng Yang
2009-04-30 1:59 ` Sheng Yang
2009-05-06 5:07 ` Sheng Yang
2009-05-07 13:21 ` Avi Kivity
2009-05-07 20:55 ` [patch 0/4] smp_send_reschedule / assigned dev host intx race v2 mtosatti
2009-05-07 20:55 ` [patch 1/4] kvm-kmod: nr_cpu_ids compat mtosatti
2009-05-07 20:55 ` [patch 2/4] kvm-kmod: smp_send_reschedule compat mtosatti
2009-05-07 20:55 ` [patch 3/4] KVM: use smp_send_reschedule in kvm_vcpu_kick mtosatti
2009-05-08 7:13 ` Gleb Natapov
2009-05-07 20:55 ` [patch 4/4] KVM: protect assigned dev workqueue, int handler and irq acker mtosatti
2009-05-10 16:31 ` [patch 0/4] smp_send_reschedule / assigned dev host intx race v2 Avi Kivity
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