netstat -B "Recv"

[elof2 at sentor.se]

Hi Christian.

So... Any news regarding this?
Should I create a bugzilla so the ball don't get dropped?

/Elof


On Fri, 6 Nov 2015, Christian Peron wrote:

> It needs to get fixed.. let me generate a patch for you and you can test it.
>
>
>> On Nov 5, 2015, at 8:51 AM, elof2 at sentor.se wrote:
>>
>> On Thu, 5 Nov 2015, Alexander V. Chernikov wrote:
>>
>>>
>>>
>>> 04.11.2015, 19:55, "elof2 at sentor.se" <elof2 at sentor.se>:
>>>> Hi!
>>>>
>>>> Question:
>>>> What do the Recv column in 'netstat -B' show?
>>>>
>>>> I thought it was tha amount of packets received, but appaently not so.
>>>>
>>>> I send 2000000 packets from a tcpreplay machine to a receiving machine.
>>>> I do it a few times.
>>>>
>>>> On the receiver I see:
>>>> netstat -in
>>>> Name Mtu Network Address Ipkts Ierrs Idrop Opkts
>>>> Oerrs Coll
>>>> ix0 1500 <Link#1> 0c:c4:7a:58:e2:3c 0 0 0 0
>>>> 0 0
>>>> ix1 1500 <Link#2> 0c:c4:7a:58:e2:3d 6000000 0 0 0
>>>> 0 0
>>>>
>>>> and then
>>>> netstat -in
>>>> Name Mtu Network Address Ipkts Ierrs Idrop Opkts
>>>> Oerrs Coll
>>>> ix0 1500 <Link#1> 0c:c4:7a:58:e2:3c 0 0 0 0
>>>> 0 0
>>>> ix1 1500 <Link#2> 0c:c4:7a:58:e2:3d 8000000 0 0 0
>>>> 0 0
>>>>
>>>> So 6000000 has increased to 8000000. Good.
>>>>
>>>> However, 'netstat -B' show:
>>>>    Pid Netif Flags Recv Drop Match Sblen Hblen Command
>>>> 25553 mon0 p--s--- 1996862 0 2000000 0 0 tcpdump
>>>>
>>>> How can the "Recv" be *lower* than "Match"?
>>>> 1996862 < 2000000.
>>>>
>>>> For every new run (fast and slow) I get the same results, slightly less
>>>> than 2000000 Recv.
>>>>
>>>> What am I missing?
>>> Well, "Recv" is read from d->bd_rcount which is not per-cpu counter and is incrementing unlocked.
>>> On the other hand, "Match" increases when filter returned match condition and we (w)locked bpf descriptor, so this one is accurate.
>>
>> Ah. Thanks.
>>
>>
>> Will you make a bugzilla out of this? Or should I? Or is it not interesting enough to fix?
>>
>> /Elof
>> _______________________________________________
>> freebsd-net at freebsd.org mailing list
>> https://lists.freebsd.org/mailman/listinfo/freebsd-net
>> To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"
>
> _______________________________________________
> freebsd-net at freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-net
> To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"
>