Re: [PATCH 0/9 Rev3] Implement batching skb API and support in IPoIB

Krishna Kumar2
2007-09-03T09:19:46Z

Hi Dave,

David Miller <davem@davemloft.net> wrote on 08/29/2007 10:21:50 AM:

> From: Krishna Kumar2 <krkumar2@in.ibm.com>
> Date: Wed, 29 Aug 2007 08:53:30 +0530
>
> > I am scp'ng from 192.168.1.1 to 192.168.1.2 and captured at the send
> > side.
>
> Bad choice of test, this is cpu limited since the scp
> has to encrypt and MAC hash all the data it sends.
>
> Use something like straight ftp or "bw_tcp" from lmbench.

I used bw_tcp from lmbench-3. I transfered 500MB and captured
the tcpdump, and analysis at various points gave pipeline sizes:

26064, 27792, 22888, 23168, 23448, 20272, 23168, 4344, 10136,
164792, 35920, 26344, 24336, 24336, 23168, 25784, 23168,

There was one huge 164K, otherwise most were in smaller ranges
like 20-30K. I ran the following test script:

SERVER=192.168.1.2
BYTES=100m
BUFFERSIZES="4096 16384 65536 131072 262144"
PROCS="1 8"
ITERATIONS=5

for m in $BUFFERSIZES
do
for procs in $PROCS
do
echo TEST: Size:$m Procs:$procs
bw_tcp -N $ITERATIONS -m $m -M $BYTES -P $procs $SERVER
done
done

Result is:
Test without batching:
# Size Procs BW (MB/s)
1 4096 1 117.39
2 16384 1 117.49
3 65536 1 117.55
4 131072 1 117.55
5 262144 1 117.58

6 4096 8 117.18
7 16384 8 117.47
8 65536 8 117.54
9 131072 8 117.59
10 262144 8 117.55

Test with batching:
# Size Procs BW (MB/s)
1 4096 1 117.39
2 16384 1 117.48
3 65536 1 117.55
4 131072 1 117.58
5 262144 1 117.58

6 4096 8 117.19
7 16384 8 117.46
8 65536 8 117.53
9 131072 8 117.55
10 262144 8 117.60

So it doesn't seem to harm e1000.

Can someone give a link to the E1000E driver? I couldn't find it
after downloading Jeff's netdev-2.6 tree.

Thanks,

- KK