Re: [PATCH v2 1/3] virtio-rng cleanup: move some code out of mutex protection

2014-09-15 Thread Michael Büsch
On Tue, 16 Sep 2014 00:02:27 +0800 Amos Kong wrote: > It doesn't save too much cpu time as expected, just a cleanup. > > Signed-off-by: Amos Kong > --- > drivers/char/hw_random/core.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/hw_random/core.c

Re: [PATCH v2 3/3] hw_random: increase schedule timeout in rng_dev_read()

2014-09-15 Thread Michael Büsch
On Tue, 16 Sep 2014 00:02:29 +0800 Amos Kong wrote: > This patch increases the schedule timeout to 10 jiffies, it's more > appropriate, then other takes can easy to hold the mutex lock. > > Signed-off-by: Amos Kong > --- > drivers/char/hw_random/core.c | 2 +- > 1 file changed, 1 insertion(+),

Re: [PATCH v2 3/3] hw_random: increase schedule timeout in rng_dev_read()

2014-09-16 Thread Michael Büsch
On Tue, 16 Sep 2014 08:27:40 +0800 Amos Kong wrote: > Set timeout to 10: > non-smp guest with quick backend (1.2M/s) -> about 490K/s) That sounds like an awful lot. This is a 60% loss in throughput. I don't think we can live with that. -- Michael signature.asc Description: PGP signature

KVM with PCI forwarding really slow after 4.1

2015-12-01 Thread Michael Büsch
Hi, I use "-device pci-assign,host=00:1a.0" to forward a USB host chip to a Win7 32 bit inside of qemu/kvm. That used to work pretty well, but it broke horribly somewhere after 4.1. With recent kernels the virtual machine boots, but is _very_ slow. It takes hours to boot. If PCI forwarding is disa

Re: KVM with PCI forwarding really slow after 4.1

2015-12-16 Thread Michael Büsch
On Tue, 1 Dec 2015 18:47:51 +0100 Paolo Bonzini wrote: > On 01/12/2015 18:09, Michael Büsch wrote: > > I use "-device pci-assign,host=00:1a.0" to forward a USB host chip > > to a Win7 32 bit inside of qemu/kvm. That used to work pretty well, > > but it broke hor