On 10/23/2009 12:06 AM, Alexander Graf wrote:
Am 22.10.2009 um 18:29 schrieb Avi Kivity <avi@xxxxxxxxxx>:
On 10/13/2009 08:35 AM, Jan Kiszka wrote:
It can be particularly slow if you use in-kernel irqchips and the
default NIC emulation (up to 10 times slower), some effect I always
wanted to understand on a rainy day. So, when you actually want -net
user, try -no-kvm-irqchip.
This might be due to a missing SIGIO or SIGALRM; -no-kvm-irqchip
generates a lot of extra signals and thus polling opportunities.
Isn't that what dedicated io threads are supposed to solve?
No. Dedicated I/O threads provide parallelism. All latency needs is to
have SIGIO sent on all file descriptors (or rather, in qemu-kvm with
irqchip, to have all file descriptors in the poll() call).
Jan, does slirp add new connections to the select set?
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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