[dns-operations] Open source release of the DNS-STATS Compactor

Jim Hague jim at sinodun.com
Tue Jun 27 11:29:40 UTC 2017


On 22/06/2017 19:37, Robert Edmonds wrote:
> Jim Hague wrote:
>> So, in summary, on old Trusty kernels and current Jessie, if you are
>> using a pcap loop with select(), set a pcap timeout and set the select()
>> timeout to the same period. It looks like it makes things better; I
>> can't be sure it cures the problem.
> 
> This sounds like a TPACKET_V3 bug that was fixed in upstream kernel 3.19
> (and likely not backported to Jessie's 3.16 kernel).
> 
> 
> https://github.com/torvalds/linux/commit/da413eec729dae5dcb150e2eb34c5e7e5e4e1b49

That certainly looks like the fix to the root cause of this. The timing
in kernel versions matches too. I've filed Debian (866094) and Ubuntu
(1700746) bugs describing the problem and suggesting the above as a fix.

Note for Ubuntu Trusty users. Since 14.04.2, desktop installs have by
default used the LTS Enablement (aka Hardware Enablement) kernel
linux-generic-lts-xenial. This doesn't have the problem. Server installs
continue to use the GA kernel (linux-image-generic), which does.
-- 
Jim Hague - jim at sinodun.com          Never trust a computer you can't lift.



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