A problem on TCP in High RTT Environment.

[Eggert, Lars]

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).

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?

Lars
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