A problem on TCP in High RTT Environment.

[Michael Tuexen]

On 12 Aug 2014, at 10:02, Eggert, Lars <lars at netapp.com> wrote:

> Hi,
> 
> On 2014-8-12, at 1:52, hiren panchasara <hiren.panchasara at gmail.com> wrote:
>> On Mon, Aug 11, 2014 at 12:59 PM, Michael Tuexen
>> <Michael.Tuexen at lurchi.franken.de> wrote:
>>> If I remember correctly, I increased
>>> kern.ipc.nmbufs and kern.ipc.nmbclusters in /boot/loader.conf
>> 
>> I believe, you just need to set kern.ipc.nmbclusters (max mbuf
>> clusters allowed) and kern.ipc.nmbufs (max mbufs allowed) should be
>> adjusted based on that.
> 
> I bumped kern.ipc.nmbclusters by a factor of 100 (from 2036224 to 203622400). As Hiren said, kern.ipc.nmbufs auto-adjusted (from 13031835 to 205111860).
Just to double check: You changed it in /boot/loader.conf, right?
> 
> However, I still see "requests for mbufs denied" immediately after reboot.
> 
> root at laurel:~ # netstat -m
> 12280/1580/13860 mbufs in use (current/cache/total)
> 12279/827/13106/203622400 mbuf clusters in use (current/cache/total/max)
> 12279/819 mbuf+clusters out of packet secondary zone in use (current/cache)
> 0/3/3/1018111 4k (page size) jumbo clusters in use (current/cache/total/max)
> 0/0/0/301662 9k jumbo clusters in use (current/cache/total/max)
> 0/0/0/169685 16k jumbo clusters in use (current/cache/total/max)
> 27628K/2061K/29689K bytes allocated to network (current/cache/total)
> 253/5481/12473 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
> 0/0/0 requests for mbufs delayed (mbufs/clusters/mbuf+clusters)
> 0/0/0 requests for jumbo clusters delayed (4k/9k/16k)
> 0/0/0 requests for jumbo clusters denied (4k/9k/16k)
> 0 requests for sfbufs denied
> 0 requests for sfbufs delayed
> 0 requests for I/O initiated by sendfile
> 
> I just noticed that the total "mbufs in use" didn't seem to have increase when I did the 100x scaling of kern.ipc.nmbclusters (and kern.ipc.nmbufs auto-adjusted). Neither did "bytes allocated to network". Is that expected?
I don't think so...

Best regards
Michael
> 
> Lars