Dns lookup spikes cpu usage

[robnitro]

Hi,
I've noticed that when running fios Video on Demand (which goes through UDP IP, the router) even with no load at all (HD takes 16mbit, I have a 30 mbit line), there are random skips on VOD when loading a page with a new address.

I have observed this and checked with htop, and I see that cpu usage spikes, despite having little to no load on the router.

Router is a buffalo g300nh and this issue happened with many versions. I don't get the issue on openwrt, but unfortunately I cannot get qosmon- dynamic downstream qos to work on there!

[ispyisail]

The new experimental, 1.5.2, version fixes a major issue with installing packages via the opkg utility introduced in 1.5.1, adds several new options for DNS resolution, and enables automatic mounting of swap partitions on USB drives.

You could try - "enables automatic mounting of swap partitions on USB drives." for more RAM

[robnitro]

??? It has nothing to do with usb or memory. I have 13 in use and 64 total.
I don't use any extra applications. I even have bwmon disabled!

[robnitro]

Ok, I narrowed it down with a bug... for some reason my download and upload qos config page was glitching up and not saving Layer7 based rules. So, I reflashed and recreated basic rules. No skipping. As soon as I added the layer 7 rules (at the bottom), like bittorrent, edonkey, voip, etc... it started skipping again.

So, for some reason, adding L7 rules to the bottom, even if not part of the traffic makes the router "skip" a split second, affecting UDP streams, such as FIOS video on demand.