You can tell it's the avast! Firewall NDIS filter service driver. You were getting thrown off by misinterpreting the Actual Duration column in the output. That column only tells you the entire cumulated time for that specific driver during the logging. So what it's just telling you was that overall was that the Unknown was DPC active - very active - during the logging. However, now look at the adjacent columns, Max Actual Duration and Avg Actual Duration, as those tell you the longest time it took to complete a DPC and the average time it took to complete a DPC, respectively. With them, you can tell that while Unknown driver did show up unusual peak in the Max with a DPC completion that took over 100ms, overall it doesn't look too bad, and it looked like for the most part DPCs were being completed in pretty short times, around 10-20ms.
Now what really stood out was under tcpip.sys, which involves network activity. It shows in its row that something was holding it up and there was a max actual DPC duration of 2.4 seconds! Wow! That took forever to complete! So what's the problem here? Well if you see it's been expanded to show the drivers under it, and it's quite evident the culprit standing out like a sore thumb: aswNdis2.sys - the avast Firewall NDIS driver - was responsible, with an average DPC completion time of 2.3 seconds over a span of 79 DPCs (determined by the Count column). Since this is an NDIS driver, it also coincides with the ugly spike in ndis.sys too.
So it's evident avast driver was responsible, but why was it? Unfortunately with the info you've given us we can't tell that far. It may be a bug in that version of the driver and that you need to update it. Or it could be that it too was held up by something like waiting on disk I/O. Whatever the case, it was taking its sweet time, and fortunately it seems that removing it fixed the problem. Just make sure to replace it with some other AV software!
