On Wed, Mar 26, 2014 at 08:22:29AM +, Gonglei (Arei) wrote:
> > > Based on discussions in:
> > > http://lists.gnu.org/archive/html/qemu-devel/2013-11/threads.html#03322
> > >
> > > About KVM_SET_GSI_ROUTING ioctl, I tested changing RCU to SRCU, but
> > unfortunately
> > > it looks like SRCU's g
On 26/03/14 09:22, Gonglei (Arei) wrote:
> Without patches, ping time can jump from 0.3ms to 2ms-30ms. With
> synchronize_srcu
> patch, ping time is worse. With synchronize_srcu_expedited patch, ping time
> is
> overall good, though sometimes ping time jump to 1ms-3ms.
Just to understand what
Il 26/03/2014 09:22, Gonglei (Arei) ha scritto:
Yes, previously I was using synchronize_srcu, which is not good. When I
changed it to synchronize_srcu_expedited, grace period delay is much better
than synchronize_srcu. Though in our tests, we can still see some impact
of KVM_SET_GSI_ROUTING ioctl
> On my system I have HZ=100 and lots of CPUs. So RCUs "every cpu has
> scheduled"
> is certainly slower than SRCUs algorithm
> (/*
> * We use an adaptive strategy for synchronize_srcu() and especially for
> * synchronize_srcu_expedited(). We spin for a fixed time period
> * (defined below) to
> > Based on discussions in:
> > http://lists.gnu.org/archive/html/qemu-devel/2013-11/threads.html#03322
> >
> > About KVM_SET_GSI_ROUTING ioctl, I tested changing RCU to SRCU, but
> unfortunately
> > it looks like SRCU's grace period is no better than RCU.
>
> Really? This is not what Christian
On 25/03/14 13:37, Paolo Bonzini wrote:
> Il 25/03/2014 04:19, Gonglei (Arei) ha scritto:
>> Based on discussions in:
>> http://lists.gnu.org/archive/html/qemu-devel/2013-11/threads.html#03322
>>
>> About KVM_SET_GSI_ROUTING ioctl, I tested changing RCU to SRCU, but
>> unfortunately
>> it looks li
Il 25/03/2014 04:19, Gonglei (Arei) ha scritto:
Based on discussions in:
http://lists.gnu.org/archive/html/qemu-devel/2013-11/threads.html#03322
About KVM_SET_GSI_ROUTING ioctl, I tested changing RCU to SRCU, but
unfortunately
it looks like SRCU's grace period is no better than RCU.
Really?