capture loss and notice of `Conn::Content_Gap` are too many

Description

I use the bro to extract files from http stream.
I installed bro with source code on ubuntu server 14.04. And I want to use virtual machine sandbox based on VirtualBox, so I installed desktop finally.
My installation document is `https://www.bro.org/sphinx/configuration/index.html#installing-pf-ring`. But I didn't start bro by `broctl`. I just started bro with command `bro -i eth0 filextraction.bro`. And there are too many packet loss.
Then I test the bro on another machine that has the same environment without desktop. And there is no packet loss.
So I'm confused.
By the way, the driver of nic is `igb`.
And I can't understand the document of `https://www.bro.org/documentation/faq.html#how-can-i-reduce-the-amount-of-captureloss-or-dropped-packets-notices` clearly.
Thanks for any help.

Environment

Dell R620
Ubuntu 14.04.04 Server LTS + kde desktop
pf_ring 6.2.0
bro 2.4 with pf_ring

Assignee

Unassigned

Reporter

LiJinmiao

Labels

External issue ID

None

Components

Affects versions

Priority

High
Configure