Re: [libvirt] [PATCH] Enable tuning of qemu network tap device "sndbuf" size
On 01/13/2011 04:21 PM, Eric Blake wrote:
On 01/12/2011 11:45 PM, Laine Stump wrote:
> This is in response to a request in:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=665293
>
> In short, under heavy load, it's possible for qemu's networking to
> lock up due to the tap device's default 1MB sndbuf being
> inadequate. adding "sndbuf=0" to the qemu commandline -netdevice
> option will alleviate this problem (sndbuf=0 actually sets it to
> 0xffffffff).
>
> Because we must be able to explicitly specify "0" as a value, the
> standard practice of "0 means not specified" won't work here. Instead,
> virDomainNetDef also has a sndbuf_specified, which defaults to 0, but
> is set to 1 if some value was given.
>
> The sndbuf value is put inside a<tune> element of each<interface> in
> the domain. The intent is that further tunable settings will also be
> placed inside this elemnent.
s/elemnent/element/
Fixed.
> Also, as with the vhost patch, I didn't get the html docs
updated for
> this addition either. I will add both in a single followup patch next
> week.
Added to my list of things to remind you about, if you forget :)
Also on my own list.
Oh, we don't have virStrToLong_ul.
Now can be changed to "we *didn't* have virStrToLong_ul" :-) Thanks!
I changed all the sndbuf things to unsigned long, and have also changed
sndbuf_specified to a bool in v2.